• Domestic science and medicine in the 19th - early 20th centuries Chemistry of the 19th century in medicine
• What are peptides? Types and types of peptides. All about peptides and anti-aging cosmetics with peptides Additional peptides are not formed
• Toxic effect on humans of hazardous chemicals
• Radioautography Method of autoradiography in cytology
• Identification of bacteria by antigenic structure
• Organic matter in wastewater What are organic compounds in water
• Hydrogen index (pH factor)
• What is the pH of water and why is it important to know it?
• Redox potential Redox systems
• Reversible redox system Reversible redox systems

(specialty "Pharmacy")

The objectives of the study of the discipline "Physical and colloidal chemistry"
The fundamental discipline "Physical and colloidal chemistry" is the basis for students to master analytical, organic, pharmaceutical chemistry, toxicological chemistry, technology of dosage forms included in the curriculum for preparing students in the specialty 040500 "Pharmacy".

PHYSICAL CHEMISTRY

Subject, tasks and methods of physical chemistry
The main stages in the development of physical chemistry. The role of domestic and foreign scientists in the development of physical chemistry. The place of physical chemistry among other sciences and its importance in the development of pharmacy. M. V. Lomonosov, D. I. Mendeleev, N. S. Kurnakov, G. I. Gess, V. F. Alekseev, N. N. Beketov - Russian scientists, founders of physical chemistry.
Basic concepts and laws of chemical thermodynamics. Thermochemistry
Subject and methods of thermodynamics. Basic concepts and definitions . Systems: isolated, closed and open. State of the system. State function. Processes: isobaric, isothermal, isochoric and adiabatic. Internal energy of the system. Job. Heat.
First law of thermodynamics. Mathematical expression of the 1st beginning. Enthalpy. Isochoric and isobaric heats of the process and the relationship between them. Hess' law. Thermochemical equations. Standard heats of formation and combustion of substances. Calculation of the standard heat of chemical reactions from the standard heats of formation and combustion of substances. Heats of neutralization, dissolution, hydration. Enthalpy diagrams. Dependence of process heat on temperature, Kirchhoff equation.
Second law of thermodynamics. Reversible and irreversible processes in the thermodynamic sense. Maximum process work. Useful work. Entropy formulation of the second law of thermodynamics. Entropy is a function of the state of the system. Entropy change in isolated systems. Entropy change during isothermal processes and temperature change. Statistical nature of the second law of thermodynamics. Entropy and its connection with the thermodynamic probability of the state of the system. Boltzmann formula.
Third law of thermodynamics. Absolute entropy. standard entropy.
Thermodynamic potentials. Helmholtz energy. Gibbs energy; connection between them. Change of Helmholtz energy and Gibbs energy in spontaneous processes. chemical potential.
Thermodynamics of chemical equilibrium
Chemical reaction isotherm equation. Thermodynamic substantiation of the law of mass action for homogeneous and heterogeneous chemical equilibrium. Chemical equilibrium constant and ways of its expression.
Isobar and isochore equations for a chemical reaction. Consequences following from these equations. The chemical equilibrium constant and the Le Chatelier-Brown principle. Calculation of the chemical equilibrium constant using tables of thermodynamic quantities.
Thermodynamics of phase equilibria
Basic concepts. Homogeneous and heterogeneous systems. Phase. Constituent substances. Components. Phase transformations and equilibrium: evaporation, sublimation, melting, change in allotropic modification. The number of components and the number of degrees of freedom. Gibbs phase rule. Prediction of phase transitions under changing conditions.
One-component systems. State diagrams of one-component systems (water, carbon dioxide, sulfur). Clausius-Clapeyron equation. Connection with the Le Chatelier-Brown principle.
Two-component (binary) systems. Diagrams of fusibility of binary systems. Thermal analysis. The concept of physical and chemical analysis (N. S. Kurnakov), application for the study of dosage forms. Raoult's law - substantiation by the method of chemical potentials based on the general law of the distribution of matter between two phases. Ideal and real solutions. Types of diagrams "composition - vapor pressure", "composition - boiling point". Azeotropes. The first and second laws of Konovalov-Gibbs. Fractional and continuous distillation (rectification). Solubility of liquids in liquids. Upper and lower critical dissolution temperatures (V. F. Alekseev). Mutually insoluble liquids. Theoretical foundations of steam distillation .
Three-component systems. Nernst's law of the distribution of substances between two immiscible liquids. Distribution coefficient. Principles of obtaining tinctures, decoctions. Extraction.
Thermodynamics of dilute solutions
Relationship between colligative properties: a relative decrease in vapor pressure, a decrease in the freezing point of the solvent, an increase in the boiling point of the solvent, and the osmotic pressure of dilute solutions of non-volatile non-electrolytes. Cryoscopic and ebullioscopic constants and their relationship with the heat of boiling and melting of the solvent.
Osmotic properties of electrolyte solutions. Isotonic ratio.
Cryometric, ebulliometric and osmometric methods for determining molar masses, isotonic coefficient .
Thermodynamics of electrolyte solutions
The theory of solutions of strong electrolytes by Debye and Hückel. The concept of the ionic atmosphere. Ion activity and its relationship with concentration. The activity coefficient and the dependence of its value on the total concentration of electrolytes in the solution. Ionic strength of the solution. Ionic strength rule. Dependence of the activity coefficient on the ionic strength of the solution.
Buffer systems and solutions: acid-base, concentration, redox. The mechanism of their action. Acetate, phosphate, ammonia, carbonate, hemoglobin buffers. Buffer capacity and factors affecting it. Importance of buffer systems for chemistry and biology.
Electrochemistry
conductors of the second kind. Specific, equivalent and molar electrical conductivity; their change with the dilution of the solution. Molar electrical conductivity at infinite dilution. Kohlrausch's law. Electrical conductivity of non-aqueous solutions. Velocity and mobility of ions. Mobility and hydration (solvation) of ions.
Electrode potentials. Origin mechanism. Nernst equation. Electrochemical potential. Standard electrode potentials. Classification of electrodes. Standard hydrogen electrode. Measurement of electrode potentials. Concentration galvanic elements. Chemical current sources.
Redox potentials. Origin mechanism. Redox electrodes. Real standard redox potential .
Ion selective electrodes. glass electrode. Other types of ion-selective electrodes. Application in biology, medicine, pharmacy. Potentiometric method for measuring pH. Potentiometric titration. The value of these methods in pharmaceutical practice. Potentiometric determination of the standard Gibbs energy of a reaction and the chemical equilibrium constant.
Kinetics of chemical reactions and catalysis
Subject and methods of chemical kinetics. Basic concepts. The reactions are simple (single-stage) and complex (multi-stage), homogeneous and heterogeneous. The rate of homogeneous chemical reactions and methods for its measurement. The dependence of the reaction rate on various factors. The law of mass action for the reaction rate. Molecularity and reaction order.
Kinetic equations irreversible reactions of zero, first, second order. half-life. Methods for determining the order of the reaction. The dependence of the reaction rate on temperature. Temperature coefficient of reaction rate. Theory of active binary collisions. Activation energy. Relationship between reaction rate and activation energy. Determination of the activation energy. Accelerated methods for determining the shelf life of drugs. Elements of the theory of the transition state (activated complex).
Complex reactions: reversible (bilateral), competing (parallel), sequential, conjugate (N. A. Shilov). The transformation of a medicinal substance in the body as a set of sequential processes; absorption constant and elimination constant. Chain reactions (M. Bodenstein, N. N. Semenov). Separate stages of a chain reaction. Unbranched and branched chain reactions. photochemical reactions. Einstein's law of photochemical equivalence. Quantum yield of the reaction.
catalytic processes. Positive and negative catalysis. Development of the doctrine of catalysis (A. A. Balandin, N. I. Kobozev). homogeneous catalysis. The mechanism of action of the catalyst. Activation energy of catalytic reactions. Acid-base catalysis. metal complex catalysis. enzymatic catalysis. Inhibition of chemical reactions. Mechanism of action of inhibitors.
Thermodynamic analysis of adsorption. Gibbs excess adsorption. Gibbs adsorption isotherm equation. Measurement of adsorption at solid-gas and solid-liquid interfaces. Factors affecting the adsorption of gases and dissolved substances. Monomolecular adsorption, Langmuir, Freindlich adsorption isotherm equation. Polymolecular adsorption. Capillary condensation, absorption, chemisorption.
adsorption of electrolytes. Nonspecific (equivalent) adsorption of ions. Selective adsorption of ions. Panet-Faience rule. Ion exchange adsorption. Ionites and their classification. exchange capacity. The use of ion exchangers in pharmacy.
Chromatography(M. S. Tsvet). Classification of chromatographic methods according to the technique of execution and according to the mechanism of the process. The use of chromatography for the preparation and analysis of medicinal substances. Gel filtration.

COLLOID CHEMISTRY

Subject, tasks and methods of colloid chemistry
The main stages in the development of colloid chemistry. T. Graham and I. G. Borshchov are the founders of colloid chemistry. The role of domestic and foreign scientists in the development of colloid chemistry (A. V. Dumansky, V. Ostwald, P. A. Rebinder). The value of colloid chemistry in the development of pharmacy.
Disperse systems
Structure of dispersed systems. Dispersed phase, dispersion medium. Quantitative characteristics of dispersion.
Classification of disperse systems: according to the state of aggregation of the dispersed phase and the dispersion medium, according to the concentration, according to the nature of the interaction of the dispersed phase with the dispersion medium. The concept of lyophilic and lyophobic disperse systems. Features of the colloidal state (nanostate) of a substance. Universality of the dispersed state of matter. Determining role of surface phenomena in colloid chemistry.
Methods for obtaining and purifying colloidal solutions. Dialysis, electrodialysis, ultrafiltration.
Molecular-Kinetic and Optical Properties of Colloidal Systems
Brownian motion (Einstein's equation), diffusion (Fick's equations), osmotic pressure. Their relationship.
Sedimentation. Sedimentation stability and sedimentation equilibrium. Centrifuge and its application for the study of colloidal systems.
Scattering and absorption of light. Rayleigh equation. Ultramicroscopy and electron microscopy of colloidal systems. Determination of the shape, size and mass of colloidal particles.
Thermodynamics of surface phenomena
Thermodynamics of the surface layer. Gibbs surface energy and surface tension. Methods for determining surface tension. Dependence of surface tension on temperature. Relationship between Gibbs surface energy and surface enthalpy. Wetting angle. Thermodynamic conditions of wetting and spreading. Hydrophilicity and hydrophobicity of the surface of solids.
Surfactant Adsorption
Thermodynamics of adsorption. Derivation of the Gibbs equation. Surface-active and surface-inactive substances. Surface tension isotherm. Shishkovsky's equation. surface activity. Duclos-Traube rule. Langmuir equation for monomolecular adsorption.
Orientation of surfactant molecules in the surface layer. Determination of the area occupied by a surfactant molecule in a saturated adsorption layer and the maximum length of a surfactant molecule.
Adsorption of surfactants on the surface of immiscible liquids. Adsorption of surfactants from solutions on the surface of solids.
Electrosurface phenomena in disperse systems.
Electrokinetic Phenomena
The nature of electrical phenomena in dispersed systems. The mechanism of occurrence of an electric charge at the interface between two phases. The structure of the electrical double layer. Micelle, micelle structure of a hydrophobic sol. Charge and electrokinetic potential of a colloidal particle.
Influence of electrolytes on the electrokinetic potential. The phenomenon of recharging colloidal particles.
electrokinetic phenomena. Electrophoresis. Relationship between the electrophoretic velocity of colloidal particles and their electrokinetic potential (Helmholtz-Smoluchowski equation). electrophoretic mobility. Electrophoretic research methods in pharmacy.
Electroosmosis . Electroosmotic method for measuring the electrokinetic potential. Practical application of electroosmosis in pharmacy.
Stability and coagulation of colloidal systems
Sedimentation and Aggregation Stability of Colloidal Systems. Aggregation and sedimentation of particles of the dispersed phase. Stability factors. Coagulation and factors that cause it. Slow and fast coagulation. Coagulation threshold, its definition. Schulze-Hardy rule. alternation of coagulation zones. Coagulation of sols by mixtures of electrolytes. Additivity rule, antagonism and synergism of ions. Colloidal protection. heterocoagulation. Peptization.
Theories of coagulation.. Theory of Deryagin-Landau-Verwey-Overbeck. The use of surfactants to control the properties of dispersed systems.
Gelation (gelatinization). Rheology of structured disperse systems.
Different classes of colloidal systems
Aerosols and their properties. Preparation, molecular-kinetic properties. electrical properties. Aggregative stability and factors determining it. Aerosol destruction. The use of aerosols in pharmacy.
Powders and their properties. Caking, granulation and sprayability of powders. Application in pharmacy.
Suspensions and their properties. Receipt. Aggregative stability and its determining factors. flocculation. Sedimentation analysis of suspensions. Foam. Pastes.
Emulsions, foams and their properties. Receipt. Types of emulsions. Emulsifiers, dispersants and their mechanism of action. Phase reversal of emulsions. Stability of emulsions and foams and its violation. Factors of stability of emulsions and foams. coalescence. Properties of concentrated and highly concentrated emulsions. The use of foams and emulsions in pharmacy.
Colloidal systems formed by surfactants: solutions of soaps, detergents, tannins, dyes. Micellar colloidal systems. Micellization in surfactant solutions. Critical micelle concentration, methods for its determination. Liposomes and vesicles. Solubilization and microemulsions; their use in pharmacy. Micellar and liposomal colloidal systems in pharmacy.
Macromolecular compounds (HMC) and their solutions.
Molecular colloidal systems. Methods for obtaining an IUD. HMC classification, polymer chain flexibility. Internal rotation of links in HMS macromolecules. Crystalline and amorphous state of the Navy.
Swelling and dissolution of the IUD. swelling mechanism. Thermodynamics of swelling and dissolution of IUDs. Influence of various factors on the degree of swelling. Lyotropic series of ions.
Viscosity of HMS solutions. Deviation of the properties of HMS solutions from the laws of Newton and Poiseuille. Bingham equation. Causes of abnormal viscosity of polymer solutions.
Methods for measuring the viscosity of HMS solutions. Specific, reduced and intrinsic viscosity. The Staudinger equation and its modification. Determination of the molar mass of the polymer by the viscometric method.
Polymer nonelectrolytes and polyelectrolytes. Polyampholytes. Isoelectric point of polyampholytes and methods for its determination.
Osmotic properties of IUD solutions. Osmotic pressure of solutions of polymeric non-electrolytes. Deviation from the van't Hoff law. Haller's equation. Determination of the molar mass of polymeric non-electrolytes. Polyelectrolytes. Osmotic pressure of polyelectrolyte solutions. Donnan membrane equilibrium.
Factors of stability of IUD solutions. Salting out, salting out thresholds. Lyotropic series of ions. Dependence of salting-out thresholds of polyampholytes on the pH of the medium. Coacervation - simple and complex. Microcoacervation. biological significance. Microencapsulation. Gelation. Influence of various factors on the rate of gelation. Thixotropy of jellies and gels. Syneresis.

Main

• Gorshkov V.I., Kuznetsov I.A. Fundamentals of physical chemistry. - M., BINOM. Knowledge Lab, 2006.
• Eremin V.V., Kargov S.I., Uspenskaya I.A., Kuzmenko N.E., Lunin V.V. Fundamentals of physical chemistry. Theory and tasks. M., Exam, 2005.
• Ershov Yu.A., Popkov V.A., Berlyand A.S., Knizhnik A.Z. General chemistry. Biophysical chemistry. M., Higher School, 2000.
• Friedrichsberg D.A. Course of colloid chemistry. - L., 1995.
• Evstratova K.I., Kupina N.A., Malakhova E.E. Physical and colloidal chemistry. - M., Higher school, 1990.
• Workshop on physical and colloidal chemistry (E. V. Bugreeva and others). - M., Higher school, 1990.

Additional

• Shchukin E. D., Pertsov A. V., Amelina E. A. Colloid chemistry. - M. 2007.
• Frolov Yu. G. Course of colloid chemistry. Surface phenomena and dispersed systems. - M., Chemistry, 2004
• Zimon D. A., Leshchenko N. F. Colloid chemistry. - M. 1999.
• Workshop and problem book on colloid chemistry, edited by Nazarov V.V., Grodsky A.S. - M. 2007.
• Shur A. M. High-molecular substances. - M., 1981.
• Zakharchenko VN Collection of tasks and exercises in physical and colloidal chemistry. - M., 1978.
• Zakharchenko V. N. Colloid chemistry. - M., 1989.
• Nikolsky B.P. (ed.) Physical chemistry. - L., 1987.
• Solovyov Yu. I. Essays on the history of physical chemistry. - M., 1984.

The program is drawn up
Assoc. Kargov S.I.
Assoc. Ivanova N.I.

N.N. Mushkambarov

PHYSICAL AND COLLOID CHEMISTRY

TEXTBOOK FOR UNIVERSITIES

Third edition, corrected and enlarged

MEDICAL INFORMATION AGENCY MOSCOW - 2008

UDC 544 (075.8) LBC 24.5ya73

Reviewers:

Dr. chem. Sciences, Professor, Moscow State University

Aslanov L. A.

Doctor of biol. Sciences, professor of MMA named after. THEM. Sechenov

Kaletina N.I.

For scientific editor:

Prof. cafe general, physical and colloidal chemistry KSMU

Timerbaev V. N.

Mushkambarov N. N.

M89 Physical and colloidal chemistry: A textbook for medical schools (with tasks). – 3rd ed., supplemented. - M .: Medical Information Agency LLC, 2008. - ... p .: ill.

ISBN 5-9231-0149-1

The textbook corresponds to the program on physical and colloidal chemistry for students of pharmaceutical faculties and institutes.

It includes 7 sections: 1. "Chemical thermodynamics", 2. "Phase equilibria and solutions", 3. "Electrolyte solutions and electrochemistry", 4. "Chemical kinetics", 5. "Surface phenomena", 6. "Disperse systems" , 7. "Lyophilic Disperse Systems".

The material is presented at a high theoretical level and is presented in a clear, concise language. A summary is provided at the end of each chapter. And after each section, a series of problems of varying degrees of difficulty with detailed solutions is given.

The textbook is intended for students of not only pharmaceutical, but also other related specialties.

UDC 544(075.8)

© N. N. Mushkambarov, 2008

© Registration.LLC "Medical Information Agency". 2008

Dedicated to teachers of physical and colloidal chemistry

Alexandra Dmitrievna Mikhailova and Larisa Evgenievna Priezzheva

with deep gratitude for their selfless and disinterested

support at a very difficult time for me,

– which, incidentally, accounted for the work on this book.

FOREWORD

This textbook was written in accordance with the "Program in Physical and Colloidal Chemistry for Students of Pharmaceutical Institutes and Pharmaceutical Faculty of Medical Schools."

I must say, there are quite a lot of textbooks and teaching aids in this discipline. However, the experience of practical teaching of physical and colloidal chemistry at MMA them. THEM. Sechenov showed that students experience serious difficulties with educational literature. That's why I created my version of the proposed course. Whether it turned out what is required is for students and teachers to judge.

The first edition of the textbook was published in September 2001. Unfortunately, due to the haste and inconsistency of the actions of the project participants, the book contained many typographical errors and editorial changes distorting the text. Therefore, after 2 months, the second, corrected, edition was published - however, in a much smaller circulation.

In this (third) edition, compared with the previous one, there are three significant differences.

a) First, double split fixed theoretical material - not only for chapters, but also for lectures: the latter was useful only for lecturers. (In particular, therefore, a summary of the previous material is now given not at the beginning of the next lecture, but at the end of the chapter.)

b) Secondly, after each section, a series of tasks is offered to the reader's attention. The initial conditions of the tasks were selected from various sources of Ph.D. biol. Sciences V.N. Tveritinov. Here, these conditions have been substantially revised, and, in addition, detailed solutions have been drawn up for all problems.

c) Thirdly, a detailed heading has been introduced into the text of the textbook. Rather, it was returned, since it was available even before the first edition, but was removed in preparation for it.

In addition, the entire text has been carefully revised, and in many places the necessary corrections, in my opinion, have been made.

The book was written in 1996-1997. Since then, I have been working in the field of a completely different science for a long time. And I am glad that interest in this textbook continues to this day.

N.N. Mushkambarov, August 2008

INTRODUCTION

AT the course of physical and colloidal chemistry includes the following 7 sections.

1. Chemical thermodynamics– the doctrine of the energy of various processes

and conditions of their spontaneous flow.

2. Phase equilibria and non-electrolyte solutions– information about the pattern

features of phase transitions and colligative properties of nonelectrolyte solutions. These are phenomena such as changes in freezing and boiling points, osmosis, etc.

3. Electrolyte solutions and electrochemistry- about the ability of electrolyte solutions to conduct current, which is associated with very important electrochemical phenomena - electrophoresis, electrolysis, EMF generation in galvanic cells, etc.

4. Chemical kinetics- the doctrine of the speed of chemical processes.

5. Surface phenomena- about the phenomena taking place on the phase interface (but not representing phase transitions): adsorption, adhesion, wetting, spreading and some other phenomena.

6. Disperse systems- about two-phase systems, of which one phase is distributed in the other in the form of a so-called. dispersed particles. A lot of objects familiar to us belong to such systems.

7. Lyophilic disperse systems- such systems are considered, where particles have a high affinity to the environment. In particular, this includes solutions of high molecular weight compounds (HMC) in suitable solvents.

In some textbooks of physical chemistry, the doctrine of the structure of matter is also expounded. There is no such section in this course, since now the structure of atoms and molecules is assigned to other chemical disciplines (general and inorganic, as well as organic chemistry).

The above list of sections indicates that physical colloid chemistry combines the functions of methodological and concrete science. How methodological science she formulates principles and methods of quantitative description chemical systems and processes. This function is performed by two key sections: 1. Chemical thermodynamics and 4. Chemical kinetics.

Indeed, energy and speed are the main characteristics of any chemical (including biochemical) process.

But as concrete science physical colloid chemistry considers certain objects and phenomena that are borderline for chemistry and physics. Mostly,

this is physical properties of chemical objects: 2. Phase transitions; 3. Electrochemical phenomena; 5. Surface phenomena; 6. Numerous physical properties disperse systems and 7. physical properties Naval Forces and their solutions.

Thus, in accordance with the two functions of physical and colloidal chemistry, its sections can be divided into two groups.

But there is another division - physical (the first four sections) and

colloidal (last three sections) chemistry.

Term colloid chemistry usually used in connection with dispersed systems (since the charged particles of the dispersed phase are called colloidal particles). Surface phenomena occur at any interface, but in the case of disperse systems, the interface is especially large and, therefore, surface phenomena are most pronounced. That is why the doctrine of these phenomena (as well as the doctrine of IUD solutions) is referred to as colloidal chemistry.

However, such a division is rather conditional, as is the sequence in which we will study the above topics is rather controversial. Perhaps it would be more logical to study kinetics immediately after thermodynamics, and surface phenomena after the section on phase equilibria. But in each sequence there are pluses and minuses, there is a conventionality. The sequence given above has historically developed and is fixed in the program.

CHEMICAL

THERMODYNAMICS

Chemical thermodynamics considers the energy aspects of various processes and determines the conditions for their spontaneous occurrence. AT

its basis - three, and together with zero - four principles of thermodynamics. If the processes are chemical, then the indicated principles of thermodynamics also apply to them. But, in comparison with purely physical processes, there is a need for a number of specific expressions - for example, for calculating the energy of a reaction, its dependence on temperature, etc. Both general thermodynamic laws and their specific application to chemical objects are of interest. That is why this section of the course is called chemical thermodynamics.

Chapter 1. BASIC CONCEPTS AND THE FIRST ORIGIN OF THERMODYNAMICS

1.1. Thermodynamic systems, states and characteristics

1. In thermodynamics, the object of consideration is always system .

Thermodynamic system - any object of nature, consisting of

a sufficiently large number of particles (at least 10 10 -10 13 ) and separated by a real or imaginary boundary from the environment.

2. There are 3 types of thermodynamic systems (Table 1.1):

a) Isolated systems - they cannot exchange either energy or mass with the environment. Examples: an isolated thermostat, the universe as a whole.

							Table 1.1
Isolated				Closed			open

b) Closed systems - they can exchange energy with the environment, but not mass. An example of a closed system is a collection of solute molecules. The external environment here is everything else, starting with the solvent (if it does not participate in the reaction). Therefore, closed systems are most often considered in chemical thermodynamics.

c) Open systems are systems that can exchange both energy and mass with the environment. Here the most important example is living objects.

3. Whatever system we take, it can be in various states. And to describe a particular state, use thermodynamic characteristics(a i ).

These characteristics can be classified in two ways. a) First, they are divided into extensive and intensive.

I. Extensive parameters depend on the amount of substance and add up

Examples are volume (V), mass (t), amount of matter (n), energy (E), related to the entire system or to its individual parts.

II. Intensive characteristics do not depend on the amount of substance and level out when systems or parts of a system come into contact. This includes parameters such as temperature (T), pressure (P), density (ρ), concentration (c).

b) The other subdivision is as follows.

I. Some characteristics can be considered as the main ones that determine the state of matter. They are called state parameters. Usually, the following characteristics are taken as such - T, P and n, i.e. temperature, pressure and amount of substance.

II. The remaining characteristics depend on these three parameters, and therefore, on the whole, on the state of the system. Therefore they are called state functions. So, for an ideal gas, energy is determined only by temperature and the amount of substance, and volume - by all three state parameters:

	– nRT ,		V = –––– .

The first expression is known from physics, and the second is the Claiperon-Mendeleev equation (PV = nRT).

The relationship between parameters and state functions is shown in fig. 1.1.

a) The value of any of them does not depend on the way the system reaches a given state, but depends only on this state itself.

b) Special terms are used for some conditions. Thus, substances (systems) are often considered under standard conditions:

Respectively, standard condition substance is 1 mole of pure

substances at standard temperature and pressure in the most stable state of aggregation.

As can be seen, to the conditions (1.3, a-c) here is added the condition of the most stable state of aggregation. For one substance, this is a gaseous state, for another - liquid, for the third - solid in the most common allotropic modification.

c) Both standard and many other states are equilibrium. AT

In an equilibrium state, the state parameters do not change spontaneously with time, and there are no flows of matter and energy in the system.

d) Finally, another important special case of states is

stationary states. Here, the state parameters are also constant, but there are flows of energy and (or) matter in the system.

e) All other states of the system are, in essence, transitional - either to an equilibrium or to a stationary state.

1.2. Thermodynamic processes

1. a) Any change in the parameters of the state (i.e., the transition of the system from one state to another) is thermodynamic process.

b) The process is led by some external influence

bringing the system out of equilibrium (i.e., its transfer to a non-equilibrium state).

c) As a result of a spontaneous process, the system

- or returns to the previous state of equilibrium,

- or goes to some other state of equilibrium

- or reaches a steady state.

2. Let us pay attention to two things here.

a) First, the system can have several equilibrium states, as shown in Fig. 1.2.

b) Secondly, if the system reaches a stationary state, then the process does not stop, but simply becomes stationary (that is, one at which constant values ​​of the state parameters are maintained).

This situation can take place in closed and open systems. For example, a healthy person is in a stationary state: all his parameters remain at a constant level. But in it all the time there are processes of exchange of matter and energy with the environment, and many of these

processes are stationary.

3. When does the system tend to an equilibrium state, and when does it tend to a stationary one?

In the case of an open system, two typical situations can be pointed out.

a) Let at the boundaries of the system be constant and identical values ​​of the intensive parameter (for example, the concentration of a substance).

Then the concentration in the system itself (initially different) also tends to the same value, which is equilibrium (Fig. 1.3, a), i.e. after reaching it, the process will stop.

					C2< C1
				C1 > Cx > C2

b) And now let the values ​​of the intensive parameter (concentration) be constant but different at the boundaries of the open system. Then, as a result of the transient process, some intermediate concentration c x is established in the system, which will then be maintained due to stationary process- the influx of matter through one boundary and the same outflow through the other boundary (Fig. 1.3, b).

Thus, a steady state is reached.

4. Reversible and irreversible processes. Of fundamental importance for thermodynamics is the division of all processes into reversible and irreversible. This subdivision takes into account how the system moves from the initial state to the final one.

a) Reversible processes - those in which the slightest opposite effect changes direction to the opposite.

This means that all intermediate states of the system and the environment in such a process are equilibrium. Therefore, often reversible processes are also called equilibrium.

b) And thermodynamically irreversible processes are those that cannot be reversed without leaving some changes in the system itself or in the environment.

From this definition it follows: after a thermodynamically irreversible process, the system under certain conditions can be returned to its original state

(i.e. implement chemical reversibility).

But this requires making some changes in the system or the environment - for example, increasing the concentration of reaction products or supplying additional heat.

Thus, thermodynamic irreversibility and chemical irreversibility are different concepts.

Note that almost every real process is thermodynamically irreversible to some extent. But the idea of ​​a perfectly reversible process is very useful.

1.3. Example: isothermal change in gas volume

An illustration of the different ways in which a system can transition from one state to another - isothermal gas expansion- shown in Fig. 1.4.

1. In the extreme version of an irreversible process, the external pressure immediately

reduced to the level of R 2 .

expands to volume

V2 = V1 P1 / P2 ,

making

external pressure P 2:

P1-dP

V1 + dV

·····arr.

reversible option

expansion, external pressure is reduced

very slowly - so gas at first

does work against pressure P 1 -

dP, then - against P 1 - 2dP, ... and only in

end - against P 2.

Obviously,

more gas than in the previous case. Let's calculate the specific value of this work:

3. Now let us assume that the gas after one or another of its expansions again

isothermally compressedto previous volume v1.

a) In the reversible version, it will be necessary to do exactly the same work on the system that the system did during expansion. There will be no changes to the system or environment.

Colloid chemistry studies the physicochemical properties of disperse systems - systems, one of the phases of which is a collection of very small particles. Such systems are widespread in nature, in everyday life, in technology, construction and other fields of activity, and also, importantly, in pharmacy. The laws of colloid chemistry underlie the processes of preparation of dosage forms, their storage and aging. Therefore, knowledge of the basics of colloidal chemistry is necessary for general pharmacists, as well as technologists of chemical and pharmaceutical production, production of products used in perfumery, cosmetics and in everyday life.

This "Course" uses the same modular system of presentation as in the volume on physical chemistry. The same applies to the design of the text and to the search engine. Due to the fact that the material included in each section is a single whole, there is no division into lectures in the book.

The author expresses his deep gratitude to all the staff of the Pyatigorsk State Pharmaceutical Academy and in particular to the staff of the Department of Physical and Colloidal Chemistry of the PGFA, whose advice, criticisms and help were used in preparing the course of lectures and writing this publication, sincere gratitude to the reviewers for the painstaking analysis of the manuscript and for constructive notes before going to print.

ACCEPTED DESIGNATIONS

A – adsorption value

a - 1) linear dimensions of particles

2) thermodynamic activity

C – 1) molar concentration

2) volume concentration

D – 1) degree of dispersion

d – diameter

2) energy

F - strength

GS - free surface energy

g - acceleration due to gravity

2) enthalpy

I – light intensity

j diff - diffusion flux

K - 1) adsorption constant

equilibrium

2) exchange constant

3) coagulation rate constant

K ’ – molar turbidity coefficient

k - 1) Boltzmann constant

l - length

M - molar mass

m - weight

NA - Avogadro's number

n – 1) amount of substance (mol)

2) refractive index

3) number of particles

P - coagulating ability

p - pressure

Q – volumetric flow rate

R - universal gas constant

r - radius

S - 1) area

2) entropy

S sed - sedimentation constant

S sp - specific surface area

T - temperature

t - time

V - volume

v – speed

w - Work

z – ion charge

a - degree of swelling

b - foam ratio

G - surface excess

g - coagulation threshold

D X – average shear of particles at

brownian motion

d is the thickness of the double electric

e - the dielectric constant

e 0 - electrical constant

z - electrokinetic potential

j - 1) volume concentration

2) electrothermodynamic

potential

h - viscosity

q - 1) contact angle of wetting

2) yield strength

l - 1) hydrophilic-lipophilic

2) wavelength

n - partial concentration

p - 1) geometric constant

2) osmotic pressure

r - density

S - sum

s - 1) surface tension

2) charge density

w - angular speed of rotation

BASIC PHYSICAL CONSTANTS

Avogadro's number NA 6.02252´1023 mol-1

Faraday number F 96487 C/mol-eq

Boltzmann constant k 1.3804´10-23 J/K

Universal gas constant R 8.314 J/mol K =

1.98725 cal/mol K =

0.082057 L atm/mol K

Electrical constant e 0 8.´1012 f/m

INTRODUCTION

1. The subject of colloidal chemistry, its place among the natural sciences

disciplines and significance for pharmacy, medicine and biology

colloid chemistry- a science that studies disperse systems and surface phenomena. Solutions of macromolecular substances are in many ways similar in properties to dispersed systems, so they are also considered in the course of colloid chemistry.

In 1861, the English chemist T. Graham, continuing the work of F. Selmi (1845), proposed to divide all chemicals into two classes according to their ability to form solutions with sharply different properties. Solutions of substances of one class - "crystalloids" in Graham's terminology - are stable, pass unchanged through plant and animal membranes, when evaporated, they usually give crystalline precipitates, diffusion in them proceeds relatively quickly, in most cases they are transparent (these are the so-called true solutions). Solutions of substances of another class are most often unstable (labile), when passing through membranes they often separate or change their properties, when they are evaporated, amorphous precipitates are formed, often not amenable to re-dissolution, diffusion in such solutions is very slow, and in most cases they have turbidity . This class of substances, according to the Greek name of their typical representatives - vegetable gums and animal glues, T. Graham called colloids (from the Greek kolla - glue), and the solutions formed by them - colloidal solutions. And although it later turned out that the division of substances into crystalloids and colloids is unlawful, since the same substances can form both true and colloidal solutions under different conditions, the term "colloidal solutions", as well as the name of the science "colloidal chemistry" derived from it » have been preserved. However, now these concepts are invested with a different content, which will be discussed below.

Most of the real bodies around us are made up of small particles - variances immersed in any medium (liquid, solid or gaseous). Dispersions include particles of the most diverse forms - grains, lumps, films, threads, air bubbles, liquid drops, capillaries, etc. The totality of such dispersions, together with the medium in which they are distributed, forms dispersed system. Thus, disperse systems consist of a continuous dispersion medium and dispersed phase- set of all variances.

Examples of natural disperse systems are rocks, soils, sand, dust, smoke, clouds and fog; plant and animal tissues, cells and intracellular formations of plants, animals, microorganisms, as well as the microorganisms themselves - bacteria and viruses. Many products of production are also dispersed systems, for example, building materials, metal alloys, paper, fabrics, food products and many dosage forms (powders, emulsions, suspensions, aerosols).
etc.). It follows that drug technology processes cannot be expertly controlled without knowledge of the basic properties of dispersed systems.

Despite the small size of the dispersions, the total surface area separating them from the dispersion medium is very large. For this reason, in dispersed systems, the surface phenomena, which largely determine their properties. Surface phenomena include processes occurring at the boundary separating contiguous (conjugated) phases. Thus, biochemical processes in living organisms occur on diverse interfaces, such as membranes that form membranes of cells, nuclei, mitochondria, etc. For a detailed consideration of these processes in normal and pathological conditions, as well as processes involving medicinal substances, it is necessary to know theory of surface phenomena.

Colloidal chemistry has another object of study - macromolecular substances (HMW) and their solutions. The point is that HMW macromolecules have sizes commensurate with the sizes of many small dispersions. Therefore, their solutions have many properties in common with dispersed systems. The need to study HMW is also due to the fact that the composition of tissues and cells of the body, cytoplasm, blood, etc. includes natural high-molecular substances - proteins, polysaccharides, nucleic acids. Solutions of various HMS are used as medicines, therefore, both the pharmacologist and the pharmacist must know the properties and structural features of such systems and be familiar with the methods of their study.

Having mainly real objects in all the variety of their properties as objects of study, colloid chemistry completes general chemical education. At the same time, there is every reason to call the science of dispersed systems and surface phenomena the physical chemistry of real bodies.

2. Signs of objects of colloidal chemistry

The objects of colloid chemistry are characterized by two common features - heterogeneity and dispersity. All the special properties inherent in them are consequences or functions of heterogeneity and dispersion.

Heterogeneity(polyphase) - a sign indicating the presence of an interfacial interface. Unlike other heterogeneous systems, dispersed systems have a high degree of fragmentation and a large number of particles of the dispersed phase.

dispersion(fragmentation) is determined by the particle size of the dispersed phase. The smaller the linear dimensions of the particles of the phase, the greater its dispersity. Quantitative dispersion can be expressed by the following characteristics:

1) linear dimensions particles a . Dimension a in the SI system - m. In the case of an isometric shape of particles - cubic or spherical, linear dimensions mean the diameter or edge of the cube, and in the case of filaments, capillaries, films and other non-isometric particles, this is the length of the smallest axis of the particle.

2) degree of dispersion D , often referred to simply as dispersion. D is the reciprocal of the linear dimensions of the particles D = 1/a . Dimension D in the SI system - m-1. D can be thought of as the number of particles that fit per unit length, i.e., per 1 m.

3) specific surface area Sud , determined by the ratio of the interfacial surface to the volume or to the mass of particles of the dispersed phase. There are two types of specific surface:

- Specific surface by volume:

,

where n - number of particles, S is the surface area of ​​one particle, V is the volume of one particle. Dimension S oud V m2/m3 (or less correct m-1).

In many cases, dispersions spontaneously take on a shape close to spherical or cubic. This is due to the fact that of all geometric bodies, the sphere and the cube have the smallest surface area for the same volume. Therefore, there are simple formulas for calculating S oud V :

-

where r - particle radius, d - its diameter;

- for systems with cubic particles

,

where a - edge length of the cube.

- Specific surface by mass:

,

where m is the mass of one particle. Because m = r V , where r is the particle matter density, then we can write: . Means,

- for systems with spherical particles

;

- for systems with cubic particles:

All three characteristics of dispersion are interconnected: with a decrease a dispersion increases D and specific surface Sud .

With a decrease in the quantitative characteristic - particle size - with the achievement of a certain degree of dispersion, a qualitative change in the properties of a heterogeneous system occurs, namely: from a variety of physical and chemical properties, surface phenomena acquire a leading role. This qualitative peculiarity begins to manifest itself when the particle size of the dispersed phase decreases to 10-4 ¸ 10-6 m, and it is especially pronounced in systems with particles 10-7 ¸ 10-9 m in size. It is precisely such systems that are actually the objects of study of colloid chemistry ( colloidal systems). Therefore, it is customary to talk about particles colloidal sizes and about special colloidal state substances, thus emphasizing the uniqueness of systems with extremely small particles.

3. Brief historical outline

The founder of colloidal chemistry is considered to be T. Graham, who performed in the 60s of the XIX century. the first systematic studies of colloidal solutions. Subsequently, colloid chemistry absorbed the results obtained in other areas of physics and chemistry and at the end of the 19th - beginning of the 20th century. in. formed into an independent branch of chemistry.

Based on the mechanical theory of capillarity, developed at the beginning of the 19th century.
T. Jung and P. Laplace, and the thermodynamics of surface phenomena, created
J. W. Gibbs in the 1870s formulated the main areas of research in colloidal chemistry: the study of the processes of formation of a new phase in homogeneous systems, the thermodynamic stability of colloidal systems, and a quantitative description of adsorption on the interface between phases. The concepts of the structure of the electrical double layer developed in 1853 by G. Helmholtz made it possible to explain electrokinetic and capillary phenomena. The creation of the theory of light scattering by J. Rayleigh contributed to the quantitative study of the optical properties of colloidal systems. Study
J. Perrin, T. Svedberg and R. Zsigmondy of Brownian motion on the basis of the theory created in 1905 by A. Einstein and M. Smoluchowski made it possible to prove the reality of the existence of molecules and the correctness of molecular kinetic concepts. In 1903, he discovered the phenomenon of chromatography and developed a chromatographic method for separating and analyzing mixtures of substances. Based on the kinetic theory of adsorption proposed in 1917 by I. Langmuir, methods were developed for studying the state of surfactant molecules in monomolecular adsorption layers. In 1928, he discovered the adsorption decrease in strength (“Rehbinder effect”) and in the 1940s–1950s, based on the development of this direction and studies of structure formation in dispersed systems, he created physical and chemical mechanics. The physical theory of the stability of colloidal systems was developed in 1937 jointly with and independently of them by E. Verwey and J. Overbeck (“the DLVO theory”).

The main areas of research in modern colloid chemistry are the thermodynamics of surface phenomena, the study of the adsorption of substances, the properties of disperse systems, the structure of the double electric layer, the creation and improvement of colloid-chemical methods of analysis and research, etc.

I. SURFACE EFFECT

CHAPTER 1

STRUCTURAL FEATURES OF THE SURFACE LAYER. SURFACE TENSION

1.1. Gibbs surface energy. Surface tension

An interfacial surface can exist only if there is a liquid or solid phase in the system. They determine the shape and structure of the surface layer - the transition region from one phase to another.

Any solid or liquid substance in the simplest case consists of molecules of the same type. However, the state of those molecules that are on the surface differs from the state of molecules that are in the bulk of the solid or liquid phase, since they are not surrounded on all sides by other similar molecules. Surface molecules are drawn into the liquid or solid, because they experience a greater attraction from the molecules in the volume of the condensed phase than from the gas molecules on the other side of the surface. This attraction causes the surface to contract as much as possible and results in some force in the plane of the surface called the force surface tension.

Therefore, liquid and solid bodies spontaneously acquire the minimum possible volume and are practically incompressible, and their stretching and rupture require significant energy costs.

This energy, imparted to the surface layer and determining its stability, is, according to J. W. Gibbs, the so-called free surface energy GS , proportional to the area of ​​the phase interface:

GS = s S , (1.1)

where s is the coefficient of proportionality, called surface tension. physical meaning s - free surface energy per unit area of ​​the phase interface or, otherwise, the work of reversible isothermal formation of a unit area of ​​the phase interface. SI dimension s - J/m2.

Surface tension can also be considered as a force acting per unit length of the surface contour, and tending to reduce the surface to a minimum for a given ratio of phase volumes. In this case, the dimension s it is more convenient to express in N/m.

The existence of surface tension explains such well-known facts: drops of water do not penetrate through small holes and gaps between the threads of umbrella or tent fabrics; water spiders and insects can run on the surface of the water, supported by an invisible surface film, rain or fog drops become spherical, etc.

When crushing a solid or liquid body, the total interfacial surface increases, due to which an increasing part of its molecules appears on the surface, and the proportion of molecules in the volume decreases. Therefore, the smaller the particles, the greater the proportion of thermodynamic functions, including the Gibbs energy of the particle, belongs to surface molecules.

1.2. Ways to reduce free surface energy

Any systems, including dispersed ones, tend to equilibrium. From the course of physical chemistry it is known that in this case there is always a tendency to a spontaneous decrease in the Gibbs energy G . This also applies to the free surface energy of dispersed systems GS .

In this case, in accordance with equation (1.1), the decrease G S can be achieved in the following ways:

a) At a constant value of surface tension by reducing the interfacial interface:

D G S = s D S .

Reducing the interface area can, in turn, also be carried out in two ways:

Spontaneous adoption by particles of such a geometric shape that corresponds to a minimum of free surface energy. So, in the absence of external force influences, a drop of liquid takes the form of a ball.

Association (aggregation) of small particles into larger ones (aggregates). In this case, a much greater energy gain is achieved, since when combined, the phase interface decreases very significantly.

It follows that, having a large supply of surface energy, dispersed systems are fundamentally aggregatively unstable and tend to a spontaneous decrease in the degree of dispersion by combining particles of the dispersed phase.

b) At a constant area of ​​the phase interface by reducing surface tension:

D G S = S D s .

In many cases, including the manufacture of dosage forms, when it is required to maintain constant particle sizes of the dispersed phase in the system, reducing the interfacial tension is the most important, and often the only way to maintain the degree of dispersion.

The decrease in surface tension is achieved by introducing into the dispersed system surfactants (surfactant), which have the ability to concentrate (adsorb) on the interface and, by their presence, reduce the surface tension.

1.3. Surfactants

The ability to lower surface tension is possessed by organic substances with asymmetric, diphilic molecules that contain both polar (hydrophilic) and non-polar (lipophilic) groups. Hydrophilic groups (-OH, -COOH, -SO3H, -NH2, etc.) provide surfactant affinity in water, hydrophobic (usually hydrocarbon radicals, both aliphatic and aromatic) provide surfactant affinity for non-polar media. The intrinsic surface tension of a surfactant must be less than that of a given solid or liquid. In the adsorption layer at the phase boundary, amphiphilic molecules are oriented in the most energetically favorable way: hydrophilic groups - towards the polar phase, hydrophobic - towards the non-polar.

Graphically, a surfactant molecule is represented by the symbol ¡¾¾¾, in which the circle denotes a hydrophilic group, and the line denotes a hydrophobic one.

1.4. Classification of surfactants

- By molecular size Surfactants are divided into high molecular weight (for example, proteins) and low molecular weight (the vast majority of surfactants listed in other types of classification).

- According to the type of hydrophilic groups distinguish non-ionic (non-ionic) and ionic (ionogenic) surfactant.

Nonionic exist in solution in the form of undissociated molecules (for example, tweens or sorbitals, alcohols).

Ionic dissociate in solution into ions, some of which actually have surface activity, while others do not. Depending on the sign of the charge of the surface-active ion, surfactants are divided into cation-active, anion-active and amphoteric.

In practice, anionic surfactants are most often used: carboxylic acids and their salts (soaps), alkyl sulfates, alkyl sulfonates, alkylaryl sulfonates, phenols, tannins, etc.

The second place in importance is occupied by non-ionic surfactants - aliphatic alcohols, their polyoxyethylene ethers of various nature, lipids.

A significantly smaller, but constantly increasing share in the production of surfactants falls on cationic (mainly derivatives of alkylamines, primary, secondary and tertiary) and amphoteric surfactants (for example, amino acids, proteins). Many alkaloids are also cationic surfactants.

- Behavior in solution all surfactants are divided into truly soluble and colloidal (or micellar, MPAV). The first group includes a large number of water-soluble amphiphilic organic compounds with small hydrocarbon radicals (alcohols, phenols, lower carboxylic acids and their salts, amines). Substances of this type exist in solution as separate molecules or ions up to concentrations corresponding to their solubility.

Of particular interest are colloidal surfactants. They are the most widely used in practice, including for the stabilization of dispersed systems, and are primarily meant by the term surfactants. Their main distinguishing feature is the ability to form thermodynamically stable ( lyophilic) heterogeneous disperse systems - micellar surfactant solutions. The minimum number of C atoms in MPAS molecules is 8 - 12, i.e. these compounds have a fairly large hydrocarbon radical.

1.5. Application of surfactants

Surfactants are used as flotation agents, dispersants, emulsifiers, detergents, components of fire extinguishing compositions, cosmetics, etc. Surfactants play an important role in biological processes.

In pharmacy, surfactants are used mainly in the form of medical soaps and stabilizers of dosage forms such as emulsions, suspensions, colloidal solutions, solubilized systems.

Medical soaps are used as detergents, disinfectants and dermatological agents. They are mixtures of ordinary sodium and potassium soaps with dyes, fragrances and various disinfectants or drugs (for example, green soap, tar, ichthyol, carbolic, sulfuric, chlorophenol, sulsen soaps).

As stabilizers for dosage forms in pharmacy, high-molecular natural surfactants such as proteins (including gelatin), gums, low-molecular natural substances - saponins, palmitate, sodium or potassium laurate, as well as synthetic surfactants - tweens (sorbitals), etc. are used.

Detergents widely used in everyday life (actually soaps, shampoos, dishwashing detergents, washing powders, etc.) are made on the basis of surfactants such as sodium (or potassium) stearate, oleate and palmitate, as well as sulfanol derivatives ( pair-sodium dodecylbenzenesulfonate).

Twin-80 Sulfanol

1.6. Surface Tension Isotherm. The equation

Shishkovsky

The dependence of the surface tension of surfactant solutions on their concentration is expressed at each given constant temperature by isotherms. The general view of such an isotherm is shown in Fig. 1.1. The surface tension isotherm leaves the point s 0 on the y-axis, which corresponds to the surface tension of a pure solvent. As the surfactant concentration increases, the surface tension gradually decreases, tending to a certain minimum constant value characteristic of each given surfactant.

Rice. 1.1. General view of the surface tension isotherm

Surface tension isotherms can be described using B. Shishkovsky's equation (1908):

https://pandia.ru/text/78/117/images/image012_28.gif" width="204" height="29 src=">,

where s - surface tension of the surfactant solution; D s - lowering the surface tension of a surfactant solution with a concentration FROM compared with s 0 - the surface tension of the solvent (eg water) at a given temperature; a and b - constants. Constant a characteristic of each homologous series; coefficient b individual for each individual surfactant.

1.7. Surfactant properties: surface activity, hydrophilic

lipophilic balance

The ability of surfactants to lower surface tension can be characterized surface activity, which depends mainly on the length of the hydrocarbon radical in the surfactant molecule. Surface activity is the derivative of the surface tension of a surfactant solution with respect to its concentration

The minus sign indicates that as the surfactant concentration increases, the surface tension of its solution decreases.

For truly soluble surfactants, surface activity is determined by the initial section of the surface tension isotherm (Fig. 1.2) at a concentration tending to zero.

Rice. 1.2. Determination of surface activity of surfactants by isotherm

surface tension

To find it, a tangent is drawn to the surface tension isotherm at the point corresponding to s 0 .The tangent is extended until it intersects the concentration axis. Surface activity is calculated as the tangent of the slope of the tangent to the x-axis:

.

For micelle-forming surfactants, surface activity can be calculated using the formula

https://pandia.ru/text/78/117/images/image017_20.gif" width="108" height="49 src="> ,

where ( b + Y n ) is the affinity (Gibbs energy of interaction) of the nonpolar part of the surfactant molecule to the hydrocarbon liquid ( b is a coefficient depending on the nature of the surfactant, Y - affinity per group - CH2-, n - number of groups - CH2 - in the hydrocarbon radical); a is the affinity of the polar group for water.

The higher the hydrophilicity of the surfactant, the greater its HLB. There is a scale of HLB numbers (D. Davis, 1960s; Griffin) ranging from 1 to 40. The HLB number on this scale can be calculated by the sum of the group numbers assigned to each group of atoms included in the surfactant molecule:

HLB = å hydrophilic group numbers +

+ å hydrophobic group numbers + 7

Here are some group numbers according to Griffin:

hydrophilic groups
hydrophobic groups

In the practical determination of HLB, the so-called reference points are used, which are the HLB numbers of some surfactants: oleic acid - 1, triethanolamine - 12, sodium oleate - 18.

Although the concept of HLB is rather formal, it allows one to roughly determine the areas of application of surfactants. For example:

Colloidal surfactants are used in the baking, pasta and confectionery industries. This improves the quality of products, increases the shelf life due to moisture retention, and reduces the consumption of raw materials. Thanks to the use of colloidal surfactants, the shape of pasta is preserved during cooking.

In the meat processing industry, surfactants are used to improve the taste of products, increase resistance to adverse factors during storage, and as biologically inert coatings on meat products.

In the food concentrate industry, colloidal surfactants are used to improve the structure of the product, to prevent clumping and sticking.

Colloidal surfactants are also used in the production of ice cream, due to which the melting process slows down, the taste and consistency of the product improves.

Collection of oil with surfactant solutions. Surfactants collect surfactant films into one drop that is easy to remove from the surface.

Due to the solubilizing effect of surfactants, they are used in medicine and pharmacy to convert water-insoluble drugs into a soluble state.

Surfactants are used as corrosion inhibitors, since they are able to form an almost monomolecular film on the surface that protects the metal from environmental influences.

7.3. emulsions

Emulsions are dispersed systems in which the dispersion phase and the dispersion medium are mutually insoluble or poorly soluble liquids (milk, butter, mayonnaise).

The particles of the dispersed phase of the emulsion have a spherical shape, since spherical particles, in comparison with particles of a different shape, have a minimum surface, and, consequently, a minimum surface energy (G surf = σ·S).

The dispersion medium of emulsions can be both polar and non-polar. Any polar liquid is usually denoted by the letter "B" (water), and non-polar - "M" (oil).

Obtaining, stability and destruction of emulsions is determined by the characteristics of the liquid-liquid interface.

7.3.1. Emulsion classification

According to the concentration of the dispersed phase (C df) there are:

diluted (C df  0.1% vol.);

concentrated (0.1 С df< 74% об.);

highly concentrated (C df >74% vol.).

According to the polarity of the dispersed phase and the dispersion medium, they distinguish:

emulsions of type I (direct) - O / W (milk);

type II emulsions (reverse) - W / O (butter).

In a direct emulsion, droplets of a non-polar liquid (oil) are distributed in a polar medium (water); in reverse emulsion, the opposite is true.

7.3.2. Methods for obtaining emulsions

Emulsions, like any other disperse systems, can be obtained by two groups of methods:

condensation methods. For example, vapor condensation. Vapor of one liquid (dispersed phase) is injected under the surface of another (dispersion medium). Under such conditions, the vapor becomes supersaturated and condenses in the form of droplets with a size of 1 µm. The result is an emulsion.

Dispersion methods, which are based on the crushing of the dispersed phase. Distinguish:

mechanical dispersion (shaking, mixing, homogenization). The industry produces mixers of various designs with propeller and turbine type agitators, colloid mills and homogenizers. In homogenizers, the dispersed phase is passed through small holes under high pressure. These devices are widely used for milk homogenization, as a result of which the average diameter of fat droplets in milk is reduced to 0.2 microns. Such milk is not settled.

emulsifying with ultrasound. It uses high power ultrasound. The most effective frequency range is from 20 to 50 kHz.

emulsification by electrical methods. The advantage is the high monodispersity of the obtained emulsions.

Send your good work in the knowledge base is simple. Use the form below

Students, graduate students, young scientists who use the knowledge base in their studies and work will be very grateful to you.

Posted on http://www.allbest.ru/

Ministry of Health of the Russian Federation

State budgetary educational institution of higher professional education

Perm State Pharmaceutical Academy

Department of Pharmaceutical Technology

KursovaIWork

On the topic: "The use of macromolecular substances in pharmacy"

Completed by: 4th year student of 44 groups

Osawa Ifueko Frances

Head: Kozhukhar Vyacheslav Yurievich

Perm, 2015

Introduction

1. Classification of macromolecular substances

2. The use of HMW in pharmacy

3. Characteristics of the Navy

4. Properties of HMB solutions

5. Factors causing violation of the stability of HMS solutions. Types of instability

6. Block diagram of the technology and quality control of HMW solutions and protected colloids

7. Technology of WMS solutions

8. Characterization of colloidal solutions

9. Properties of colloidal solutions

10. Factors causing violation of the stability of solutions of protected colloids

11. Characterization of protected colloids

12. Technology of solutions of protected colloids

13. Solutions of semicolloids

14. Quality assessment and storage of HMS solutions and protected colloids

15. Improvement of HMW solutions and protected colloids

Literature

Introduction

The rapid development of the chemistry of macromolecular substances (HMW) in recent years has contributed to their widespread use in various industries. Of particular interest is the use of VMV in pharmacy.

In pharmaceutical practice, HMW are used as medicinal (proteins, hormones, enzymes, polysaccharides, plant mucus, etc.), and excipients, packaging materials. Excipients are widely used as stabilizers, emulsifiers, shapers, solubilizers to create more stable disperse systems in the production of various dosage forms: suspensions, emulsions, ointments, aerosols, etc. The introduction of new HMW into the technology made it possible to create new dosage forms: long-acting multilayer tablets, spansules (granules impregnated with HMW solution) microcapsules; ophthalmic medicinal films; children's dosage forms, etc.

Solutions of HMW are stable systems, however, under certain conditions, a violation of stability is possible, which leads to salting out, coacervation, gelling. Therefore, knowledge about the intensity of interaction between the particles of the dispersed phase and the dispersion medium is very important for the technologist, since this significantly affects the choice of the method for preparing the drug.

In modern pharmaceutical practice, medicinal substances are used, which are protected colloids, which consist of a colloidal component and a macromolecular substance. Therefore, solutions of these groups of drugs are considered in one topic.

1. Classification of macromolecular substances

Macromolecular substances are called natural or synthetic substances with a molecular weight of several thousand (not less than 10-15 thousand) to a million or more.

2. ApplicationVMBinpharmacy

Of particular importance is the use of HMW as excipients. According to the effect of HMW on the technological characteristics of drugs, they are classified into separate groups.

high molecular weight colloidal solution pharmacy

3. FeatureVMB

HMW molecules are amphiphilic in nature, since they contain polar (-COOH, -NH2, -OH, etc.) and non-polar (-CH3, -CH2, -C6H5) functional groups.

The more polar radicals in the HMW molecule, the better it is soluble.

The solubility of HMS depends on the size and shape of their molecules.

The process of dissolution of HMW occurs in 2 stages

4. Properties of solutionsVMB

Combining them with true solutions:

Distinguishing them from true solutions:

5. Factors causing violation of the stability of solutionsWWII. Kindsinstability

6. Block diagram of technology and quality control of solutionsWWIIand protected colloids

7. TechnologyHMW solutions

When preparing solutions unlimited swelling substances are guided by the general rules for the preparation of solutions of low molecular weight substances, taking into account the properties of medicinal substances and solvents.

Rp.: Pepsini2.0

Acid hydrochlorici 5 ml

Aquae purificatae 200 ml

Miss. Da. signa. 1-2 tablespoons 2-3 times a day with meals.

Pepsin activity is manifested at pH 1.8-2.0. In a strongly acidic environment, pepsin is inactivated, which leads to a special technology for its solutions: first, an acid solution is prepared, in which

155 ml of purified water is measured into the stand, 50 ml of a solution of hydrochloric acid (1:10) is added, and 2.0 g of pepsin is dissolved in the resulting solution, stirred until it is completely dissolved. The solution, if necessary, is filtered through gauze folded in several layers (preferably through a glass filter No. 1 or No. 2) into a vial for dispensing.

Dissolution limited swelling substances requires the use of additional technological methods that facilitate the transition of the swelling stage to the dissolution stage.

Rp.: Solutionis Gelatinae 5% 50,0

Da. signa.1 tablespoon per 2 hours.

Weigh 2.5 g of dry gelatin, place in a tared porcelain cup, pour 10 times the amount of cold water and leave to swell for 30-40 minutes. Then the rest of the water is added, the mixture is placed in a water bath (temperature 60-70°C) and dissolved with stirring until a clear solution is obtained. Dilute with water to the desired weight. The resulting solution, if necessary, is filtered into a dispensing bottle.

Solution before usegelatinshouldwarm up, because solution can condense

Rp.: Mucilaginis Amyli 100.0

Da. signa.For 2 enemas.

The solution is prepared by weight as follows: 2 parts of starch are mixed with 8 parts of cold water and added with stirring to 90 parts of boiling water. Stir while heating to a boil. If necessary, you can strain through cheesecloth.

If the concentration is not indicated, then prepare a 2% solution according to the prescription: starch - 1 h;

cold water - 4 hours;

hot water - 45 h.

To prevent salting out, electrolytes should be added to the HMW solution in the form of aqueous solutions. solutions

Solution preparationmethylcellulose:

1. Methylcellulose is poured with hot water (80-90 ° C) in the amount of 1/2

from the required volume of the resulting solution.

2. Cool to room temperature.

3. Add the rest of the cold water and leave in the refrigerator for 10-12 hours.

4. Strain through glass filter No. 2.

8. Featurecolloidal solutions

Colloidal solutions present is an ultramicroheterogeneous system in which the structural unit is a complex of molecules, atoms and ions called micelles.

A micelle is a particle of a dispersed phase surrounded by a double electric layer. The size of micelles is in the range from 1 to 100 nm.

The structure of a micelle

9. Propertiescolloidal solutions

elementary structural unit - micelle;

characteristic Brownian motion;

low diffusion capacity;

· low osmotic pressure;

low capacity for dialysis;

the ability to scatter light in all directions when viewing solutions in reflected light (a characteristic Tyndall cone is formed);

micelles in a colloidal solution are in chaotic motion, they are characterized by Brownian motion;

Sedimentation-resistant systems;

· aggregatively and thermodynamically unstable systems that exist due to stabilization due to the appearance of a double electric layer.

10. Factors causing a violation of the stability of protected solutionscolloids

11. Characterization of protected colloids

Protected colloid preparations do not pass through physiological membranes, so they exhibit only local action.

12. Solution technology protected colloids

Rp.: solutionis Protargoli 2% 100 ml

Da. Signa. For washing the nasal cavity.

100 ml of water in a wide-mouth bowl and leave alone. The drug swells, and the particles of protargol, gradually dissolving, sink to the bottom of the stand, giving access to the next portions of water to the drug.

Solutions of protected colloids must not be filter through a paper filter, because the ions of iron, calcium, magnesium contained in the paper cause coagulation with loss of the drug for filter.

If necessary, these solutions are filtered through glass filters No. 1 and No. 2 or filtered through an ashless filter paper.

If, in addition to water, glycerin is prescribed in the composition of the solution, then protargol is first ground in a mortar with glycerin and after it swells, gradually add water

When prescribing collargol in concentrations up to 1% its solutions are prepared in a stand or vial for vacation, dissolving collargol in water purified

Purified water is filtered (can be filtered) into a glass bottle for dispensing, collargol is poured out and the contents of the bottle are shaken until the collargol is completely transferred into the solution.

When prescribing collargol in concentrations of more than 1%, its solutions are prepared in a mortar, rubbing collargol with purified water

Rp.: Solutionis Collargoli 2% 200 ml

Da.signa.For douching.

Collargol is placed in a mortar, a small amount of purified water is added, the mixture is left for 2-3 minutes to swell, rubbed, and then the remaining amount of water is added little by little while stirring.

If necessary, the collargol solution is filtered through a glass filter No. 1 or No. 2 or filtered through a loose ball of cotton wool, washed with hot water.

Ichthyol is not compatible:

· with acids(sulfoichthiolic acid precipitates)

with salts of calcium, ammonium, copper, mercury, silver, lead and zinc (insoluble salts of sulfoichthyolic acid are formed)

With salts of alkaloids and other nitrogen-containing organic bases (insoluble sulfoichthyol salts of alkaloids and other nitrogen-containing organic bases are formed)

with electrolytes (potassium bromide; ammonium, sodium and calcium chlorides; potassium iodide) (coagulation occurs)

with sodium tetraborate, with caustic and carbonic alkalis (precipitates and ammonia is released)

Rp.: Solutionis Ichthyoli 1% 200 ml

Da. signa.For lotions.

Weigh 2.0 g of ichthyol into an old porcelain cup, gradually add 200 ml of water with continuous stirring with a glass rod, then, if necessary, strain into a dispensing bottle.

Rp.: solutionis Ichthyoli 2% 100 ml

Glycerini10,0 Misce.

Da. signa. For tampons.

10.0 g of glycerol are weighed into a calibrated stand and 100 ml of purified water are measured there, shaken until smooth. 2.0 ichthyol is weighed into a tared porcelain cup, a solution of glycerol in water is added in parts and triturated until completely dissolved, leaving part of the water-glycerin solution in the stand. The resulting solution of ichthyol, if necessary, is filtered into a vial for dispensing. Porcelain cup is rinsed with the rest of the water-glycerine solution and filtered into a dispensing bottle.

13. Solutionssemicolloids

Solutions of semicolloids- these are systems that, under certain conditions, are true solutions, and when the concentration of the dispersed phase changes, they become sols in a colloidal state.

These include solutions of tanides, soaps, some organic bases (etacridine lactate).

The preparation of solutions of semicolloids is carried out according to the general rules for the preparation of solutions.

Rp.: Tannini3,0 Aquae purificatae 100 ml

Miss.Da. signa. For wetting the skin with burns.

98.2 ml of warm purified water is measured into a stand and 3.0 g of tannin is dissolved in it (KVO = 0.61 ml/g). The solution is filtered through a cotton swab into a vial for dispensing.

14. Quality assessment and storage of WMS solutionsand protectedcolloids

The quality control of HMW solutions and colloids is carried out according to:

active substances;

instructions and orders of the Ministry of Health of the Russian Federation

Quality control includes all types of intra-pharmacy control:

· written;

a survey;

organoleptic (color, taste, smell), as well as uniformity and absence of mechanical impurities;

physical (total volume or mass, which, after the preparation of the medicinal product, should not exceed the norms of permissible deviations);

chemical control (optional);

holiday control.

Storage conditions solutions of HMW and protected colloids depend on the properties of the medicinal substances that make up the prescription. If there are no special instructions, extemporaneous solutions of HMW and protected colloids are stored in a cool, dark place for 10 days.

HMW solutions and colloidal solutions are released in orange glass vials with additional labels “Shake before use”, “Keep in a cool, dark place”, “Keep out of the reach of children”.

15. Improvement of HMW solutionsand protectedcolloids

Literature

1. Biopharmacy: Proc. for stud. pharmaceutical universities and faculty / A.I. Tikhonov, T.G. Yarnykh, I.A. Zupanets and others; Ed. A.I. Tikhonov. - X .: Publishing House of NFAU; Golden Pages, 2003.- 240 p.

2. Gelfman M.I. Colloid chemistry / Gelfman M.I., Kovalevich O.V., Yustratov V.P. - S.Pb. and others: Lan, 2003. - 332 p.

3. Sovereign Pharmacopoeia of Ukraine / Sovereign undertaking “Scientific-Expert Pharmacopoeia Center”. - 1st view. - Kh.: PIREG, 2001.-556 p.

4. Additional speeches and stosuvannya in the technology of medicinal forms: Dovіdkovy posіbnik / F.Zhoglo, V.Voznyak, V.Popovich, Ya.Bogdan. - Lviv, 1996. - 96 p.

5. Evstratova K.I., Kupina N.A., Malakhova E.E. Physical and colloidal chemistry: Proc. for pharmaceutical universities and faculties / Ed. K.I. Evstratova. - M.: Higher. school, 1990. - 487 p.

6. Extemporaneous recipe (technology, zastosuvannya). Rіdkі likarskі forms: Dovіdnik / О.І. Tikhonov, V.P. Chernikh, T.G. Yarnikh ta in.; For red. O.I. Tikhonova.- Kh .: View of NFAU, 2000.- 208s.

7. Mashkovsky M.D. Medicines: In 2 volumes - 14th ed., Revised, corrected. and additional - M.: LLC "New Wave Publishing House", 2000. - T. 1.- 540 p.

8. Ordinance of the Ministry of Health of Ukraine dated 07.09.93 No. 197 “On the approval of instructions for the preparation in pharmacies of medicinal forms with a rare dispersion medium”.

9. Ordinance of the Ministry of Health of Ukraine dated 30.06.94 No. 117 “On the procedure for issuing prescriptions and dispensing medicines and prescriptions for medical recognition from pharmacies”.

10. Polymers for medical purposes /Ed. Senoo Manabu. - M.: Medicine, 1991. - 248 p.

11. Handbook of extemporaneous recipes / Ed. A.I.Tikhonova. - K.: MORION, 1999. - 496 p.

12. Technology and standardization of medicines. Sat. scientific works. / Ed. V.P. Georgievsky and F.A. Koneva - H .: "Rireg", 1996, - S. 606-698.

13. Tikhonov O.I., Yarnikh T.G. Pharmacy technology of drugs / Ed. O.I.Tikhonova. - H.: RVP "Original", 1995. - 600 s.

14. Tikhonov A.I., Yarnykh T.G. Technology of drugs: Proc. for pharmaceutical universities and faculty: Per. from Ukrainian / Ed. A.I. Tikhonov. - X .: Publishing House of NFAU; Golden Pages, 2002. - 704 p.: 139 ill.

15. Tikhonov O.I., Yarnikh T.G. Likiv technology: Handbook for students of pharmaceutical faculties of the Higher Medical School of Ukraine III-IV level of accreditation: Translated from Russian / Edited by O.I.Tikhonova. - Vinnytsya: View of "New book", 2004. - 640 p.

16. Friedrichsberg D.A. Course of colloid chemistry: A textbook for universities. - 2nd ed., revised. and additional - L.: Chemistry, 1984. - 368 p.

17. Pharmaceutical and biomedical aspects of drugs. Proc. for listeners in-comrade, factor. advanced training of pharmacy specialists: B 2

t. / I.M. Pertsev, I.A. Zupanets, L.D. Shevchenko and others; Under. ed. THEM. Pertseva, I.A. Zupants. - X .: Publishing House of NFAU, 1999.- T.1.- 448 p.

18. Extemporaneous formulation (technology, application). Liquid dosage forms: Directory / A.I. Tikhonov, V.P. Chernykh, T.G. Yarnykh and others; Ed. Academician A.I. Tikhonov. - X .: Publishing House of NFAU, 2000. - 208 p.

19. Enciclopaedia of Pharmaceutical Technology / Ed. J. Swarbrick, I.C. boylan. - 2nd - New-York, Basel: Marcek Dekker, Inc., 2002. - Vol. 3. - 3032 p.

20 European Pharmacopeia, 4th Ed. - Strasbourg: council of Europe, 2001. -2416 p.

21. British Pharmacopoeia, 2000. - 2346 p.

22. Guide to good Manufacturing Practice for medicinal Products/ The Rules Governing Medicinal Products in the European Community.- Vol.IV.-P.135.

Hosted on Allbest.ru

...

Similar Documents

The concept of solutions of macromolecular compounds (VMC). The process of swelling of the IUD: its stages, causes, pressure and degree. Viscosity of disperse systems and solutions of HMS, methods of its measurement. Structural and relative viscosity. coagulation structures.

abstract, added 01/22/2009


Characterization of solutions containing buffer systems and having the ability to maintain a constant pH. The use of buffer solutions and their classification. The essence of the buffer action. Buffer properties of solutions of strong acids and bases.

test, added 10/28/2015


Colloidal chemistry as a science that studies the physicochemical properties of heterogeneous, highly dispersed systems and high-molecular compounds. Production and methods of purification of colloidal solutions. The use of gels in the food industry, cosmetics and medicine.

presentation, added 01/26/2015


Constants and parameters that determine the qualitative (phase) state, quantitative characteristics of solutions. Types of solutions and their specific properties. Methods for obtaining solid solutions. Features of solutions with eutectics. Solutions of gases in liquids.

abstract, added 09/06/2013


The role of osmosis in biological processes. Diffusion process for two solutions. Formulation of Raoult's law and consequences from it. Application of cryoscopy and ebullioscopy methods. Isotonic van't Hoff coefficient. Colligative properties of electrolyte solutions.

abstract, added 03/23/2013


Alloys of silicon with nickel, their properties and industrial applications. Thermodynamic modeling of the properties of solid metal solutions. Theory of "regular" solutions. Thermodynamic functions of formation of intermetallic compounds. Calculation of component activities.

thesis, added 03/13/2011


The nature of the solute and solvent. Methods for expressing the concentration of solutions. Effect of temperature on the solubility of gases, liquids and solids. Factors affecting dissolubility. Relationship between normality and molarity. Laws for solutions.

lecture, added 04/22/2013


Classification of dispersed systems. The main factors of stability of colloidal solutions. Methods for their production (dispersion, condensation) and purification (dialysis, ultrafiltration). Micellar theory of the structure of colloidal particles. Coagulation with electrolyte mixtures.

presentation, added 11/28/2013


Phase equilibria, synthesis modes and properties of strontium, barium-containing solid solutions of composition (Sr1-xBax) 4M2O9 (M-Nb, Ta) with perovskite structure. Characterization of starting materials and their preparation. Methods for calculating the electronic structure of solids.

term paper, added 04/26/2011


Physical properties of water, dipole moment of the molecule. The mechanism of formation of solutions. Influence of pressure, temperature and electrolytes on the solubility of substances. Thermal Nernst theorem. The main ways of expressing the composition of solutions. The concept of the mole fraction.

• Activities and pedagogical views of Jan Amos Comenius
• The rate constant is calculated by the formula Rate constant value
• Phase diagrams of two-component systems "polymer - solvent" Phase diagrams of two-component systems "polymer - solvent"
• Fine and hyperfine structure of optical spectra
• How to learn chemistry on your own from scratch: effective ways
• Properties and characteristics of alkenes
• Characteristics of a student from the place of internship
• Characteristics for a student who had an internship at an enterprise: writing rules
• Biography of Faraday. Great scientists. Michael Faraday. discovery of electromagnetic rotation
• Modern innovations in education

• Substituents on the benzene ring are divided into two groups Reactions of the benzene ring
• Types of chemical reactions in organic chemistry Electrophilic addition reactions
• Methods for separating heterogeneous mixtures
• Polymethacrylic acid
• General characteristics of the elements of the VI A subgroup Elements 6a of the subgroup
• Theoretical foundations of physics
• Graph theory in chemistry. graph theory. Basic definitions and theorems of graph theory
• Algebra and harmony in chemical applications
• Tests on the course "Ecology and nature management
• WWF Russia Director Igor Chestin: Yakutia is among the leaders I know that you travel a lot… Why do you need this