Lecture #2
on the course "Analysis and control
quality of medicines"
1

Brief outline of the lecture

1. Classification of drugs. general characteristics
pharmacopoeial analysis of drugs. Reagents used in
pharmacopoeial analysis.
2. Physical Chemical properties medicinal substances
(aggregate state, appearance, color, crystallinity,
polymorphism and methods of its research. Solubility.
Acid-base properties of medicinal substances).
3. Physical constants of drugs and methods
their definitions.
4. Methods for the identification of medicinal products
5. Impurities in medicines, classification,
methods of identification and analysis. The concept of stress
trials
6. Methods quantitative analysis medicinal
funds
2

LV classification

1. Inorganic substances (derivatives of s-, p- and d elements).
2. Organic matter
2.1. Aliphatic compounds (alkanes,
haloalkanes, alcohols, aldehydes, ethers,
carbohydrates, amino acids, carboxylic acids)
2.2. aromatic compounds (phenols,
aromatic carboxylic acids, aromatic
amino acids, phenylalkylamines,
sulfonamides);
2.3. Steroid compounds, prostaglandins
3

Classification of drugs (continued)

2.3. Heterocyclic compounds
2.3.1. Compounds containing one heteroatom
(derivatives of furan, benzofuran, pyridine,
quinoline, isoquinoline, etc.);
2.3.2. Compounds containing two or more
identical heteroatoms (pyrazole derivatives,
imidazole, benzimidazole, purine, pteridine and
etc.).
2.3.3. Compounds containing two or more different
heteroatoms (derivatives of thiazole, benzothiazole,
oxazolidins, etc.).
2.4. organoelement substances.
3. Radiopharmaceuticals.
4. Biotechnological (high molecular weight)
medicinal substances
4

Pharmaceutical analysis (analysis of drugs and drugs)

Pharmaceutical analysis is a branch of the science of
chemical characterization and measurement of biologically active substances at all
production stages - from raw material control to evaluation
the quality of the resulting drug, studying its stability
(setting expiration dates) and standardization of dosage forms and
LS.
Peculiarities:
1. An analysis is being made of completely different
nature, structure and properties of substances
2. The measured concentrations (contents) are in
range from 10-9 (1 ppb) to 100%.
3. Not only individual drugs are analyzed, but also their
5
mixtures.

Pharmaceutical analysis (classifications)

Depending on the tasks:
1. Pharmacopoeial analysis
2. Stage-by-stage control of the production of drugs and drugs
3. Analysis of individual drugs
4. Pharmacy express analysis
5. Biopharmaceutical analysis
Depending on the result:
1. Quality
2. Quantitative
3. Semi-quantitative (limit tests)
6

Pharmaceutical Analysis Criteria

1. Selectivity (specificity, selectivity) -
the ability to unambiguously evaluate the determined
component by the selected method regardless of the others
substances present (impurities, decomposition products and
etc.) in the test sample within the specified
application range.
2. Sensitivity
2.1. Limit of detection
2.2. Limit of definition
3. Correctness - a reflection of the difference between the true
the content of the determined component and
experimental result of the analysis.
4. Reproducibility (precision) -
characteristic of the "scattering" of the results near
the average value of the determined value.
5. Robustness - a characteristic of the stability of the technique
in time.
These criteria are established during the validation process 7
methods (techniques)

Pharmacopoeial analysis of drugs (general structure)

state of aggregation,
appearance,
color, crystallinity,
polymorphism
Authenticity
First identification
(specific method)
Second identification
(confirmation)
Definition
physical
constants,
farm properties
Pharmacopoeial
LV analysis
(general structure)
melting point, temperature
solidification, dropping point,
distillation temperature limits
boiling temperature,
density and viscosity of liquids, specific
rotation and refractive index
solubility, pH
Definition
impurities
quantitative
definition
Indicators of microbial purity,
sterility, non-pyrogenicity, absence of viral bodies
8

chemical name

IUPAC nomenclature used
(International Union Pure Applied Chemistry)
pure and applied chemistry)
(much less often - trivial names)
1) determine the type of nomenclature (substitutive, radical-functional);
2) determine the type of characteristic group to be adopted
for the main;
3) determine the parent structure (main chain, senior
cyclic system);
4) give a name to the original structure and main groups;
5) give a name to prefixes;
6) carry out numbering;
7) combine partial names into a common full name,
adhering to alphabetical order for all defined prefixes.
In addition to the name, the structural chemical formula is indicated
and gross formula.
9

10. Design example

2-(naphthalen-1-ylmethyl)-4,5-dihydro-1H-imidazole
hydrochloride
10

11. An example of constructing the chemical name of an organic drug

Choice of numbering: from the nitrogen atom,
closest to the senior deputy
(C=O-group).
Establishment of the ancestral
structures: 1,4-benzodiazepine;
Name including substituents: 2,3dihydro-2H-1,4-benzodiazepin-2-one;
List of deputies: by
alphabetically - 7-Cl-1-Me-5-Ph
Total:
7-chloro-1-methyl-5-phenyl-2,3dihydro-2H-1,4-benzodiazepin-2-one
H3C
O
N
Cl
N
11

12. An example of constructing the chemical name of an organic drug (2)

2-methyl-3-hydroxy4,5-di
(hydroxymethyl)pyridine
HO
Oh
4
3
5
2
HO
6
N
1
12

13. Description of the drug

1. Aggregate state (liquid, gas, solid
substance, crystallinity), color, smell, special
properties (hygroscopicity, easy oxidation on
air, etc.), particle size (for solid substances).
2. Polymorphism is a phenomenon characteristic of
solids - the ability of a substance in a solid
able to exist in various
crystalline forms at the same
chemical composition.
When describing solvates (hydrates), we use
the term "pseudopolymorphism" (variability
solvate or hydrate composition).
13

14. Description of LP - polymorphism

Polymorphic forms exhibit
same chemical properties
in solutions and melts, but in
solid state their physical
(density, T melt, compressibility)
and physico-chemical properties
(solubility and as a consequence
bioavailability) may
differ significantly.
That of the polymorphic forms,
which is less important
free enthalpy is
most thermodynamically
stable, and other forms
may be in the so-called.
"metastable" state. 14

15. Polymorphism (examples)

Allotropic forms of carbon: a) lonsdaleite; b) diamond;
c) graphite; d) amorphous carbon; e) C60 (fullerene);
f) graphene; g) single-layer nanotube
15

16. Polymorphism (examples)

Nimesulide (the formula shows torsion rotations and
packing corresponding to polymorphic form I)
16

17. Polymorphism (examples)

Nimesulide (the formula shows the total torsion
rotations and packing corresponding to polymorphic form II)
17

18. Polymorphism (examples)

Data
x-ray
diffraction for
forms I and II
nimesulide
18

19. Polymorphism (examples)

Differential Scanning Calorimetry
(DSC) polymorphic forms of nimesulide
19

20. Polymorphism and bioavailability

Dissolution kinetics of two polymorphic
forms of nimesulide (37C, pH 7.5)
20

21. Methods for the study of polymorphic forms

1. X-ray diffraction (powder and
crystals)
2. Differential scanning
calorimetry, microcalorimetry
3. Thermogravimetry
4. Moisture absorption analysis
5. FT-IR spectroscopy
6. Raman spectroscopy
7. Study of solubility (kinetics
dissolution)
21

22. Particle size (powders, pellets)

For sizing
particles use sets
sieves with square
holes,
made from inert
materials. Degree
grinding is indicated with
using a number
sieves (side size
holes in µm).
Modern methods– methods
laser scanning
22

23. Solubility

Solubility data means
approximate solubility at temperature
20°C unless otherwise stated. Expression
"soluble in so many parts" should be understood
as an indication of the number of milliliters of solvent
(represented by the specified number of parts), in
which we will dissolve 1 g of a solid.
Sometimes to indicate the solubility of a substance
descriptive terms are used (easy, bad,
difficult, etc.).
Classical description of solubility (handbooks)
– 1 g of a substance dissolves in X g of solvent at
temperature T.
23

24. Solubility

25. Acid-base properties

Not listed in normative documents By
quality control of drugs, but have a decisive
value during testing,
solubility in aqueous media, choice
methods and methods of analysis, as well as
absorption, distribution,
bioavailability of drugs.
According to acid-base properties, all
substances are divided into non-ionic (non-ionic)
acid / non-base) and ionic -
acids (exhibiting mainly
acid properties), bases, ampholytes.
25

26. Methods for determining physical constants

1. Gravimetry
2. Refractometry
3. Polarimetry
4. Viscometry (capillary,
rotary)
5. Thermometry
26

27. Relative density (d20)

Relative density d is the ratio
mass of a certain volume of a substance to a mass equal to its
volume of water at a temperature of 20°C.
The relative density d is determined using
pycnometer, density meter, hygrostatic balance or hydrometer
accurate to decimal places indicated in private
article. Atmospheric pressure is not taken into account when weighing,
since the error associated with it does not exceed unity in
third decimal place.
In addition, two other definitions are commonly used.
The relative density of a substance is
the ratio of the mass of a certain volume of a substance at
temperature of 20 ° C to a mass equal to its volume of water at
temperature 4oC.
Density ρ20 is the ratio of the mass of a substance to its volume
at a temperature of 20°C. Density is expressed in kilograms per
cubic meter (1 kg / m3 \u003d 10 -3 g / cm3). The most common measurement
density is expressed in grams per cubic centimeter
27
(g/cm3).

28. Relative density

29. 30. Refractive index

31. Refractometers

32. 33. Optical rotation

34. Optical rotation

35. 36. Polarimetry (equipment)

37. Viscosity

Viscosity (internal friction) - the property of fluid bodies to exert
resistance to movement of one of their parts relative to
another.
Fluid bodies can have a Newtonian type of flow.
Newtonian fluids are systems whose viscosity is
does not depend on shear stress and is constant
value according to Newton's law.
For Newtonian fluids, there are dynamic,
kinematic, relative, specific, reduced and
characteristic viscosity. For non-Newtonian fluids
characterized mainly by structural viscosity.
Dynamic viscosity or viscosity coefficient η is
tangential force per unit surface,
which is also called the shear stress t, expressed in terms of
pascals (Pa), which must be applied in order to
move a layer of liquid with an area of 1 m2 with a speed (v) 1
meter per second (m.s-1) at a distance (x) 1 meter
relative to another layer, parallel to the slip area.
37

38. Viscosity (capillary method)

Methodology. test liquid,
having a temperature of 20°C, if
private article not marked other
temperature, poured into the viscometer
through the tube (L) in such quantity that
fill in the extension (A), but at the same time
liquid level in expansion (B) must
stay below the exit to the ventilation
tube (M). Viscometer in vertical
position is immersed in a water bath at
temperature (20+/-0.1)оС, if in a private
the article does not indicate another temperature,
holding it in this position for at least
30 minutes to set the temperature
balance. The tube (M) is closed and
increase the liquid level in the tube (N)
so that she is
about 8 mm above the mark (E).
Keep the liquid at this level,
closing the tube (N) and opening the tube (M).
Then open the tube (N) and measure
the time during which the liquid level
will drop from mark (E) to mark (F),
stopwatch accurate to one-fifth
seconds.
38

39. Temperature limits of distillation

40. Melting point

1. Capillary method for determining temperature
melting. Melting point, determined
capillary method, represents the temperature at
which the last solid particle of the compacted column
substances in the capillary tube passes into the liquid phase.
2. Open capillary method - used for
substances having an amorphous structure, not rubbing into
powder and melting below the boiling point of water,
such as fats, wax, paraffin, petroleum jelly, resins.
3. Instant melting method - used for solid
substances that are easily powdered.
4. Dropping point - the temperature at which
conditions below, the first drop of molten
of the test substance falls from the cup (fats, waxes,
oils).
5. Solidification temperature - the maximum temperature,
at which the supercooled liquid solidifies.
40

41. Determination of melting point (instrumental)

Video of the melting process
Color video high resolution allows you to study
substances which melt with decomposition or have
coloring. Instruments can also be used to study phenomena
41
thermochromism.

42. Authenticity (methods)

1. chemical reactions Authenticity:
A. General reactions to authenticity by
functional groups (primary
aromatic amines, alkaloids,
esters, etc.)
B. Specific reactions to ions
B. Specific reactions to
organic matter
42

43. Examples of identification reactions by functional groups

Reaction to the primary aromatic amino group:
43

44. Examples of identification reactions by functional groups

Reaction to the primary amino group
(ninhydrin reaction):
44

45. Specific reactions to ions

46. Specific reactions to ions

47. Specific reactions to ions

Specific reactions to ions
subdivided:
1. Precipitation reactions
2. OB reaction
3. Decomposition reactions
4. Complex formation reactions
47

48. Specific reactions of authenticity

49.

50.

51.

52.

53.

54.

55.

56. 57. Authenticity (methods)

2. Instrumental Methods
2.1. IR spectroscopy (FT-IR)
2.2. Absorption spectrophotometry
in the UV and/or visible region of the spectrum
2.3. Chromatographic methods (TLC,
GC, LC)
2.4. Electrophoresis, capillary
electrophoresis (including peptide
mapping)
57

58. Authenticity (methods)

3. Physical methods (definition
physical constants):
3.1. melting point, boiling point,
distillation temperature limits.
3.2. Relative density.
3.3. refractive index.
3.4. Angle of optical rotation.
3.5. Viscosity determination.
58

59. Authenticity (proof)

Establishing the authenticity of the PL is carried out
at least 2 ways!
First identification - specific
instrumental method (usually IR spectrometry) + additional method
(for example, chromatographic or
chemical method)
Second identification - confirmation
authenticity (using the definition
physical constants, additional
chemical methods, absorption
spectrophotometry, etc.).
59

60. Impurities (classification)

1. General technological impurities - falling into the process
production.
1.1. Reagent impurities (SO42-,Cl-, sulfate ash, etc.)
1.2. Impurities from contact with process equipment (HM,
As, Pb, Cd, Fe, etc.)
1.3. Residual organic solvents
1.4. water, moisture
2. Specific impurities - characteristic of a particular drug and
include:
2.1. Synthesis intermediates and specific reagents
2.2. Synthesis by-products
2.3. Associated impurities (chemically related analogues and
residual amounts of pesticides and supertoxicants - for drugs
natural origin)
2.4. Stereoisomers-impurities (impurities of enantiomers)
2.5. Products of decomposition and interaction with technological
impurities, moisture, air oxygen, organic
solvents, etc.
3. Mechanical impurities
60

61. Impurities

1. Volatile (characterized by a loss in mass when
drying).
2. Inorganic (set when determining
sulfate ash, heavy metals, etc.).
3. Structure-related impurities (determined
chromatographic methods or electrophoresis).
Separately classified toxic
(influence the pharmacological
effect - i.e. are invalid) and
non-toxic (indicate the degree of purification
LV) impurities.
61

62. Weight loss on drying (gravimetric method)

It is a total non-specific indicator,
characterizing the presence of water (moisture), residual 62
organic solvents in drugs

63. Definition of water

1. Distillation (distillation) - for liquids
2. Titrimetric method (K.
Fisher, micromethod) - for solids
63

64. Physical and chemical properties characterizing purity

Transparency and degree of turbidity. Clear solutions -
when illuminated by an electric lamp on a black background, do not
the presence of undissolved particles is observed. Degree
turbidity is determined by comparing the test
substances with a standard (or with a solvent).
The color of liquids is determined by comparison
test solutions with an equal volume of one of the standards at
daylight on a matte white background.
Adsorption capacity - set according to
discoloration of the dye (methylene blue) in the drug solution
certain concentration.
Impurities of colored substances (light-absorbing impurities)
– for uncolored substances, absorbance is determined
a solution of a drug in water or an organic solvent in a visible
region of the spectrum.
64

65. Definition of ash

gravimetric method
1. Total ash (MP, a number of organic
LV) - sample burning (1.0000 g)
of the test sample in the crucible at T
about 500оС (30 min), after
cooling determine the mass of the residue.
2. Sulphated ash - sample
wetted with 1 ml of H2SO4 and then
act as in determining the total
ash.
65

66. Definition of "heavy" metals

A. Sample preparation stage:
1. Dissolution in water (for drugs that are highly soluble in water) or
in a mixture with organic solvents (acetone, dioxane);
2. "Wet" mineralization (for organic matter) –
2.1. combustion of flammable substances with a mixture of MgSO4 and H2SO4 (Т=800оС).
2.2. mineralization with a mixture of H2SO4 and HNO3 (heating to
200°C).
2.3. mineralization using microwave heating
(Teflon vessels, 2.5 GHz).
3. "Dry" mineralization - fusion with MgO (Т=600оС).
B. Qualitative and/or semi-quantitative analysis
(chemical reaction with sulfide ion):
1. High-quality - standard-free (lack of color with
reagent)
2. Semi-quantitative analysis - comparison of color with a standard,
containing the maximum amount of lead ions (reference).
66
B. Quantitative analysis - AAS or AES method.

67. Residual organic solvents (classification)

The classification is based on the potential
danger of solvents for the human body and
environment.
Class 1. Solvents, the use of which
should be avoided (carcinogens and
environmental supertoxicants - benzene, TCA,
1,2-dichloroethane, 1,1-dichloroethane, 1,1,1-trichloroethane).
Class 2. Solvents, the use of which
should be limited (non-genotoxic
carcinogens, substances with significant
toxicity) - acetonitrile, hexane, dioxane,
xylene, methanol, nitromethane, pyridine, chloroform,
toluene, ethylene glycol, etc.
67

68. Residual organic solvents (classification, continued)

Class 3 Low toxicity solvents (with
low potential for toxicity in humans,
do not require setting limits
content - less than 5000 ppm (mcg / g) or
0.5%) - acetone, butanol-1, butanol-2, heptane,
DMSO, pentane, acetic acid, propanol-1,
propanol-2, ethanol, THF, pentane, etc.
Class 4. Solvents for which
missing data on
toxicity (isooctane, petroleum ether,
trifluoroacetic acid, etc.).
68

69. Residual organic solvents

Gas Chromatography Method (GC Screening)
A. Sample and solution preparation
comparisons
1. Dissolving a weighed portion of the test sample
in water (for drugs soluble in water).
2. Dissolving a weighed portion of the test sample
in dimethylformamide (DMF).
3. Dissolution of a weighed portion of the test sample
in 1,3-dimethyl-2-imidazolidinone.
Because most organic solvents
"included" in the crystal lattice (or in
structure in the form of solvates) drugs, sample preparation
should include complete dissolution of the sample with
"destruction" of the lattice and possible solvates.
CH3
H
N
CH3
O
CH3
N
O
N
CH3
69

70. Residual organic solvents (analysis)

B. Headspace sample preparation -
carried out to transfer OOR from solution to
vapor-gas phase (heating in hermetically sealed
sealed container).
B. Gas chromatographic analysis of the vapor phase (semi-quantitative analysis with
separation on a medium capillary column
polarity).
70

71. Specific impurities

1. Synthesis intermediates and specific reagents
(including catalysts)
1.1. Inorganic substances - cations, anions,
complex compounds
1.2. organic matter
1.3. genetically modified microorganisms,
viruses, etc.
O
N
N
HN
N
N
N
CH3
Irbesartan (azide ion impurity)
71

72. Specific impurities

The largest group of impurities in organic drugs -
chemically related chemical
substances (their number is limited so far only
capabilities of separation and detection methods). How
harder than chem. structure, the more
impurities must be normalized.
O
H3C
H3C
CH3
O
H
H
CH3
H
O
H
H3C
O
O
CH3
O
H
H
S
O
H
O
S
H
H
Br
O
H
CH3
O
CH3
H
O
S
H
O
O
H3C
CH3
CH3
Spironolactone
H3C
O
H
H
O
CH3
H3C
O
CH3
H
H
H
O
O
H
H
H
H
O
72
O

73. Specific impurities

Oh
Oh
O
Paracetamol
O2N
H3C
N
H
Oh
HO
H2N
O
Side effects
products
synthesis
Cl
H3C
O
N
H
Oh
O
H3C
H3C
N
H
Intermediate
products
synthesis
N
H
Cl
Oh
O
H3C
N
H
73

74. Specific impurities

Associated impurities in the natural substance
origin:
A. chemically related analogues
(have biological (pharmacological)
activity, may be potentially dangerous
for the body)
B. pesticide residues and
supertoxicants (polychlordioxins,
polychlorinated biphenyls), products
vital activity of microorganisms
(aflatoxins) - unconditional toxic
substances strictly regulated at the ppm level and
ppb (µg/g or ng/g)
74

75. Associated impurities in drugs of natural origin (example)

Oh
O
Oh
Oh
O
H
H
H
HO
H
Oh
H
Oh
cholic acid
H
HO
O
H
Oh
ursodeoxycholic acid
H
Ursodeoxycholic acid
(extracted from bear bile)
H
H
Oh
Oh
chenodeoxycholic acid
75

76. Specific impurities

Decomposition and interaction products:
1. with technological impurities (heavy metals
(d-elements are catalysts for many OB reactions, including those involving O2), iron ions,
residues of reagents with reactive
functional groups),
2. with moisture (hydrolysis reactions are possible (complex
esters, amides, carbamates, etc.), moisture absorption
always associated with a decrease in the content of active
substances),
3. with air oxygen (oxygen sensitive
substances such as polyunsaturated fatty acids
acids, strong reducing agents)
4. with residual organic solvents (series
organic solvents - ethylene oxide, dichloromethane,
dichloroethane, acetic acid, etc. - enough
reactive and react with the drug during storage).
76

77. Stress tests -

Stress tests
several factors
(temperature, reagents, lighting) with
the purpose of proving selectivity
methods for assessing impurities, studying
education and identification
impurities, additional study
drug stability during storage.
77

78. Stress tests (conditions)

1. Temperature - sequential
temperature rise during storage
drug sample at 10°C (50, 60, etc.);
2. Humidity (increase in relative humidity
air during storage of the drug sample up to 75% and
higher).
3. Reagents - acid solutions (1M HCl),
alkalis (1M or 0.1M NaOH), H2O2 (3-30%)
when heated.
4. Exposure to light (UV light,
intensity - not less than 200 Wh/m2)
78

79. Quantification

Analysis methods (classification,
brief description, application
for the analysis of drugs and drugs, comparative
evaluation) is the subject of the following
at least 3 lectures!
Thank you for attention!

Introduction

1.2 Errors in Pharmaceutical Analysis

1.3 General principles for testing the identity of medicinal substances

1.4 Sources and causes of poor quality of medicinal substances

1.5 General requirements for purity tests

1.6 Methods of pharmaceutical analysis and their classification

Chapter 2. Physical Methods of Analysis

2.1 Verification of physical properties or measurement of physical constants of drug substances

2.2 Setting the pH of the medium

2.3 Determination of clarity and turbidity of solutions

2.4 Estimation of chemical constants

Chapter 3. Chemical Methods of Analysis

3.1 Features of chemical methods of analysis

3.2 Gravimetric (weight) method

3.3 Titrimetric (volumetric) methods

3.4 Gasometric analysis

3.5 Quantitative elemental analysis

Chapter 4. Physical and chemical methods of analysis

4.1 Features of physicochemical methods of analysis

4.2 Optical methods

4.3 Absorption methods

4.4 Methods based on emission of radiation

4.5 Methods based on the use of a magnetic field

4.6 Electrochemical methods

4.7 Separation methods

4.8 Thermal methods of analysis

Chapter 5

5.1 Biological quality control of medicines

5.2 Microbiological control of medicinal products

List of used literature

Introduction

Pharmaceutical analysis is the science of chemical characterization and measurement of biologically active substances at all stages of production: from the control of raw materials to the assessment of the quality of the obtained medicinal substance, the study of its stability, the establishment of expiration dates and the standardization of the finished product. dosage form. Pharmaceutical analysis has its own specific features that distinguish it from other types of analysis. These features lie in the fact that substances of various chemical nature are subjected to analysis: inorganic, organoelement, radioactive, organic compounds from simple aliphatic to complex natural biologically active substances. The range of concentrations of analytes is extremely wide. The objects of pharmaceutical analysis are not only individual medicinal substances, but also mixtures containing a different number of components. The number of medicines is increasing every year. This necessitates the development of new methods of analysis.

Methods of pharmaceutical analysis need to be systematically improved due to the continuous increase in the requirements for the quality of drugs, and the requirements for both the degree of purity of medicinal substances and the quantitative content are growing. Therefore, it is necessary to widely use not only chemical, but also more sensitive physical and chemical methods for assessing the quality of drugs.

The requirements for pharmaceutical analysis are high. It should be sufficiently specific and sensitive, accurate in relation to the standards stipulated by the Global Fund XI, VFS, FS and other NTD, carried out in short periods of time using the minimum number of subjects medicines and reagents.

Pharmaceutical analysis, depending on the tasks, includes various forms of drug quality control: pharmacopoeial analysis, step-by-step control of the production of medicines, analysis of individual dosage forms, express analysis in a pharmacy and biopharmaceutical analysis.

Pharmacopoeial analysis is an integral part of pharmaceutical analysis. It is a set of methods for studying drugs and dosage forms set forth in the State Pharmacopoeia or other regulatory and technical documentation (VFS, FS). Based on the results obtained during the pharmacopoeial analysis, a conclusion is made on the compliance of the medicinal product with the requirements of the Global Fund or other regulatory and technical documentation. In case of deviation from these requirements, the drug is not allowed to be used.

The conclusion about the quality of the medicinal product can only be made on the basis of the analysis of the sample (sample). The procedure for its selection is indicated either in a private article or in a general article of the Global Fund XI (issue 2). Sampling is carried out only from undamaged sealed and packed in accordance with the requirements of the NTD packaging units. At the same time, the requirements for precautionary measures for working with poisonous and narcotic drugs, as well as for toxicity, flammability, explosiveness, hygroscopicity and other properties of drugs, must be strictly observed. To test for compliance with the requirements of the NTD, multi-stage sampling is carried out. The number of steps is determined by the type of packaging. At the last stage (after control by appearance) take a sample in the amount necessary for four complete physical and chemical analyzes (if the sample is taken for controlling organizations, then for six such analyses).

From the "angro" packaging, point samples are taken, taken in equal quantities from the top, middle and bottom layers of each packaging unit. After establishing homogeneity, all these samples are mixed. Loose and viscous drugs are taken with a sampler made of an inert material. Liquid medicinal products are thoroughly mixed before sampling. If this is difficult to do, then point samples are taken from different layers. The selection of samples of finished medicinal products is carried out in accordance with the requirements of private articles or control instructions approved by the Ministry of Health of the Russian Federation.

Performing a pharmacopoeial analysis allows you to establish the authenticity of the drug, its purity, to determine the quantitative content of the pharmacologically active substance or ingredients that make up the dosage form. Although each of these steps has its own specific purpose they cannot be viewed in isolation. They are interrelated and complement each other. For example, melting point, solubility, pH of an aqueous solution, etc. are criteria for both authenticity and purity of a medicinal substance.

Chapter 1. Basic Principles of Pharmaceutical Analysis

1.1 Pharmaceutical analysis criteria

At various stages of pharmaceutical analysis, depending on the tasks set, criteria such as selectivity, sensitivity, accuracy, time spent on the analysis, and the amount of the analyzed drug (dosage form) are important.

The selectivity of the method is very important when analyzing mixtures of substances, since it makes it possible to obtain the true values of each of the components. Only selective methods of analysis make it possible to determine the content of the main component in the presence of decomposition products and other impurities.

Requirements for the accuracy and sensitivity of pharmaceutical analysis depend on the object and purpose of the study. When testing the degree of purity of the drug, methods are used that are highly sensitive, allowing you to set the minimum content of impurities.

When performing step-by-step production control, as well as when conducting express analysis in a pharmacy, an important role is played by the time factor spent on the analysis. For this, methods are chosen that allow the analysis to be carried out in the shortest time intervals and at the same time with sufficient accuracy.

In the quantitative determination of a medicinal substance, a method is used that is distinguished by selectivity and high accuracy. The sensitivity of the method is neglected, given the possibility of performing an analysis with a large sample of the drug.

A measure of the sensitivity of a reaction is the limit of detection. It means the lowest content at which the presence of the determined component can be detected by this method with a given confidence level. The term "limit of detection" was introduced instead of such a concept as "discovered minimum", it is also used instead of the term "sensitivity". The sensitivity of qualitative reactions is influenced by such factors as the volumes of solutions of reacting components, concentrations of reagents, pH of the medium, temperature, duration experience.This should be taken into account when developing methods for qualitative pharmaceutical analysis.To establish the sensitivity of reactions, the absorbance index (specific or molar), established by the spectrophotometric method, is increasingly used.In chemical analysis, the sensitivity is set by the value of the limit of detection of a given reaction.Physicochemical methods are distinguished by high sensitivity The most highly sensitive are radiochemical and mass spectral methods, which make it possible to determine 10 -8 -10 -9% of the analyte, polarographic and fluorimetric methods 10 -6 -10 -9%, the sensitivity of spectrophotometric methods is 10 -3 -10 -6%, potentiometric 10 -2%.

The term "analysis accuracy" simultaneously includes two concepts: reproducibility and correctness of the obtained results. Reproducibility characterizes the scatter of the results of an analysis compared to the mean. Correctness reflects the difference between the actual and found content of the substance. The accuracy of the analysis for each method is different and depends on many factors: calibration measuring instruments, the accuracy of weighing or measuring, the experience of the analyst, etc. The accuracy of the analysis result cannot be higher than the accuracy of the least accurate measurement.

UDC 615.015:615.07:53

ANALYSIS OF DRUGS FOR PHARMACOKINETIC

RESEARCH

Dmitry Vladimirovich Reyhart1, Viktor Vladimirovich Chistyakov2

Department of Organization and Management in the Sphere of Medicines Circulation (Head - Corresponding Member of the Russian Academy of Medical Sciences, Prof. R.U. Khabriev) of the Moscow State Medical Academy. THEM. Sechenov,

2 Center for Chemistry of Medicinal Products - VNIHFI (general director - K.V. Shilin), Moscow

A review of sensitive and specific analytical methods used in the study of the pharmacokinetics of drugs was carried out. The advantages and limitations of the use of enzyme immunoassay, high performance liquid chromatography with fluorescent and mass spectrometric detection are shown. The use of a particular method in assessing the pharmacokinetics of drugs in each case is determined by the structure of the test compound and the equipment of the laboratory.

Key words: liquid chromatography, fluorescence and mass spectrometric detection, enzyme immunoassay, pharmacokinetics.

The study of pharmacokinetics is based mainly on the assessment of the concentration in the patient's body of a drug substance (PM) at certain points in time after taking the drug. The object of the study is blood (whole, serum, plasma), urine, saliva, feces, bile, amniotic fluid, etc. The most accessible and most frequently studied blood and urine samples.

Measuring the concentration of a drug can be divided into two stages: 1 - isolation of a specific drug substance from a biological object, concentration of the test compound, separating it from the main endogenous components; 2 - separation of a mixture of compounds, identification of drugs and quantitative analysis.

The study of the concentration of the drug in the blood provides information on the duration of circulation of the drug in the body, the bioavailability of the drug, the effect of concentration on the pharmacological effect, therapeutic and lethal doses, the dynamics of the formation of active or toxic metabolites.

The study of the concentration of the drug in the urine allows you to evaluate the rate of elimination of drugs and kidney function. The concentration of metabolites in the urine is an indirect indicator of the activity of metabolizing enzymes.

The study of biological material includes measuring the mass (volume) of the sample, the release of the drug (metabolites) from 532

sample cells, separation of whole cells (for example, when analyzing blood) or parts of cells (when analyzing tissue homogenates), adding an internal standard, separating proteins, cleaning the sample (centrifugation, filtration), extraction, re-extraction, concentration and conversion of test substances into convenient for the analysis of derivatives, the main procedures for processing blood and urine samples, respectively (Fig. 1).

The “ideal” analytical method for measuring drug concentration should have high sensitivity, specificity and reproducibility, the ability to work with small volumes, ease of material preparation, low cost and ease of equipment maintenance, reliability and automation, ease of personnel work and versatility (the ability to analyze various classes of drugs) .

To obtain reliable data, it is necessary to make a correction for the stability of the active substance and / or product (s), as well as the degree of its biotransformation in the analyzed biological media.

The validation of a method should be based on its intended application, and the calibration should take into account the concentration range of the test sample. It is strongly discouraged to use two or more methods of sample analysis on the same material with a similar range of calibration values.

Exists big number methods for determining the concentration of drugs in biological fluids: chromatographic, microbiological, spectrophotometric, polarographic, immunological (radioimmune, immunoenzymatic), radioisotope and other methods.

The critical parameters of the method are sensitivity, speed, accuracy, the ability to work with a small amount of biomaterial and cost.

In table. 1 compares analytical methods for drug analysis.

The most widely (up to 95% of studies) in practice is the method of highly effective

Rice. 1. Basic procedures for handling blood and urine samples.

liquid chromatography (HPLC) with various types detection.

The advantages of HPLC compared, for example, with gas-liquid chromatography (GLC) are the absence of restrictions on the thermal stability of the analyzed preparations, the ability to work with aqueous solutions and volatile compounds, and the use of “normal-phase” and “reverse-phase” chromatography options. Many of the types of detection are non-destructive.

enzyme immunoassay, HPLC with fluorescent detection, HPLC with mass spectrometric detection, which are currently actively used in pharmacokinetic studies.

ELISA method

The method of enzyme immunoassay (ELISA) was proposed in the early 70s of the last century. The principle of ELISA is the interaction of specific protein proteins

Comparative characteristics drug analysis methods

Methods Absolute sensitivity, g Sensitivity, points Complexity, points Selectivity, points Universality Total assessment, points

Liquid chromatography:

UV detector 10-7 3 -3 4 4 8

fluorescent detector 10-8 - 10-9 4 -3 5 2 8

mass spectrometric detector 10-11 - 10-12 5 -5 5 4 9

Immunological 10-10 - 10-11 5 -1 4 1 9

Gas Chromatography:

electron capture detector 10-10 5 -4 4 2 7

flame ionization detector 10-8 - 10-9 4 -3 2 4 7

mi; detection methods used in HPLC have higher specificity.

Let us consider the features of highly sensitive methods that allow us to analyze nanogram amounts of drugs (Table 1):

a body with an analyte acting as an antigen. The higher the concentration of the substance-antigen, the more antigen-antibody complexes are formed. For the quantitative analysis of complex formation at-

two approaches change - with preliminary separation of the complex (heterogeneous methods) or without its separation (homogeneous methods). In both cases, a sample with an unknown analyte concentration is added to serum in which the antibody is complexed with a labeled analog of the analyte, and the substance from the analyte is displaced from the complex. The amount of displaced labeled analogue is proportional to the concentration of the substance in the sample. Having determined how much of the labeled analog turned out to be displaced from the complex (or, on the contrary, remained bound), it is possible to calculate the desired level of the substance in the sample. Pre-calibration is carried out using standard solutions (with standard concentrations of the test substance).

Reagent kits are produced - the so-called diagnosticums (antiserum, an enzyme connected with the drug, a substrate, a cofactor, standard solutions for calibration), designed for 50-200 tests. For analysis, 0.05-0.2 ml of the patient's blood serum is usually sufficient.

Immunoenzyme methods have high sensitivity and specificity. Diagnostic kits are relatively cheap and have a longer shelf life than kits for radioimmunoassays. When using ELISA, the need to separate the antigen-antibody complex is eliminated - a rather complicated procedure, with a relatively high risk of error. The immunoenzymatic method can be performed in any hospital or outpatient laboratory; devices have been developed that provide full automation of analysis.

Ease of analysis, high sensitivity, accuracy, reproducibility,

the moderate price of equipment and reagents - all this creates the prospect for the widespread introduction of immunological methods into medical practice.

High performance liquid chromatography with fluorescence detection

In HPLC, the detector generates an electrical signal whose strength is proportional to the concentration of the analyte dissolved in the mobile phase. In the first liquid chromatographs (ion-exchange), the mobile phase passed through the column with the sample components was collected in small vessels, and then using titrometry, colorimetry, polarography, etc. the content of the component in this portion was determined. In other words, sample separation processes

and definitions of its quantitative composition were separated in time and space. In a modern liquid chromatograph, these processes are provided by one instrument.

Any physicochemical property of the mobile phase (absorption or emission of light, electrical conductivity, refractive index, etc.) that changes in the presence of molecules of separable compounds can be used to detect sample components. Of the existing 50 physicochemical detection methods, 5-6 are currently actively used.

Sensitivity is the most important characteristic of the detector. If sensitivity is defined in terms of the baseline noise amplitude, and the noise is expressed in terms of physical units, then the sensitivity of the photometric detector will be expressed in units of optical density, refractometric - in units of the refractive index, voltammetric - in amperes, conductometric - in siemens. In pharmaceutical analysis, sensitivity is expressed in terms of the minimum amount of analyte. Degree of sensitivity various types detectors is given in Table. 1.

Despite the fact that at present 80% of chromatographs are equipped as standard with spectrophotometric detectors, fluorescence detection is becoming more widespread, especially when determining the concentration of compounds that can “glow” under the action of exciting radiation. The luminescence intensity is proportional to the intensity of the exciting light. The study of emission spectra (fluorescence and phosphorescence) is a more sensitive and specific method than the study of absorption spectra.

The fluorescence spectrum of a substance in many cases is a mirror reflection of the absorption band with the lowest energy and is usually located next to this band on its long wavelength side. This method it is most convenient to use in the study of drugs that have their own fluorescence (chloroquine, doxorubicin, doxazosin, atenolol, indomethacin, propranolol, tetracyclines, quinidine, etc.). Some drugs can be relatively easily converted into fluorescent compounds (derivatization process), such as hydrocortisone (sulfuric acid treatment), meperidine (condensation with formaldehyde), 6-mercap-topurine, and methotrexate (oxidation with potassium permanganate). Other drugs with active functional groups can be condensed with fluorescent reagents.

gentami - fluorescamine (chlordeazepoxide, novocainamide, sulfonamides, etc.), 7-nitrobenzo-2,1,3-oxadiazole (propoxyphene, etc.), etc. At the same time, it should be noted that, with high sensitivity and selectivity, fluorescent detection methods are limited by the range of drugs that have natural fluorescence, and the derivatization process in quantitative analysis is costly.

High Performance Liquid Chromatography with Mass Spectrometric Detection

A highly sensitive version of the modern HPLC detector used for pharmacokinetic studies is the mass spectrometer. The mass spectrometric detector can significantly reduce the analysis time, in particular, by eliminating the preparatory stage (extraction). This method makes it possible to simultaneously identify several substances, and this eliminates errors associated with the presence of inseparable components.

Mass spectrometry is one of the most promising methods for the physicochemical analysis of drugs. Traditionally, organic mass spectrometry is used to solve two main problems: the identification of substances and the study of the fragmentation of ionized molecules in the gas phase. The combination of a mass spectrometer with a liquid chromatograph significantly expanded the possibilities of the classical method. With the advent of new ionization methods, such as "electrospray" (ESI - English electrospray ionization - ionization in an electric field at atmospheric pressure) and "MALDI" - ionization by laser desorption, the list of molecules that can be studied by this method has expanded significantly.

Currently, the combination of HPLC and an "electrospray" mass spectrometric detector is widely used in the study of pharmacokinetics and bioequivalence of drugs. Initially, the ESI method was developed under the leadership of L.N. Gall, and in 2002 D. Fen-nu and K. Tanaka were awarded the Nobel Prize for the development of identification methods and structural analysis biological macromolecules and, in particular, methods of mass spectrometric analysis of biological macromolecules. There are three stages in the mechanism of formation of ionized particles. The first is the formation of charged droplets at the capillary section. Through the applied voltage, the charge is redistributed in the solution, the positive ions are trapped

spilling out at the exit. With a strong applied field (3-5 kV), a jet is formed from the top of the cone, which then scatters into small drops. The second stage is the gradual reduction in the size of the charged droplets due to the evaporation of the solvent and the subsequent disintegration of the droplets up to the formation of true ions. The charged droplets move through the atmosphere towards the opposite electrode. The third stage is repeated cycles of separation and reduction in the volume of droplets until the solvent is completely evaporated and ions are formed in the gas phase.

Modern LC/MS systems (LC/MS - liquid chromatography/mass-spectrometry) make it possible to register the total ion current (TIC - total ion current), control the specified ions (SIM - selected ion monitoring), and control the specified reactions selective reaction monitoring (SRM - English selected reaction monitoring).

Total ionic current (TIC) analysis provides data on all compounds sequentially exiting the chromatographic column. Mass chromatograms resemble chromatograms with UV detection, with the area under the peak corresponding to the amount of substance. When determining target ions (SIM), the operator can limit the detection range of the required compounds by isolating, for example, minor substances. The SRM method has the highest sensitivity and specificity when the ion current is recorded using one selected ion characteristic of the compound under study (in ESI ionization and registration of positive ions, this is usually the MH+ molecular ion).

Recently published papers discuss the possibility of quantitative analysis of organic substances in biological objects without chromatographic separation using multi-ion detection and internal control as a deuterium labeled analogue. In particular, for lipid molecules, the concentration range (from pico- to nanomolar) was determined, at which the authors observed linear dependence the intensity of the ion current on the concentration of the substance. An increase in the concentration of compounds in the solution led to ion-molecular interactions during ionization and violation of linearity.

A method for the quantitative determination of prostaglandins and polyunsaturated fatty acids using electrospray ionization - mass spectrometry without chromatographic separation using an internal standard and registration of negative ions. In work

Yu.O. Caratasso and I. V. Logunova, the sensitivity of mass spectrometry in the study of a potential antiarrhythmic agent was 3 ng/0.5 ml of blood plasma.

When choosing an analytical method, it must be borne in mind that the use of ELISA is limited by the presence of required reagents, fluorescent detection, and the need for intrinsic fluorescence in the test compound. Although the above limitations are not significant for mass spectrometric detection, the cost of equipment today remains quite high, and this type of analysis requires special skills.

LITERATURE

1. Aleksandrov M.L., Gall L.N., Krasnov N.V. and others. Extraction of ions from solutions at atmospheric pressure - new method mass spectrometric analysis // Dokl. Acad. sciences of the USSR. - 1984. - T.277. - No. 2. -

2. Karatasso Yu.O., Logunova IV, Sergeeva MG et al. Quantitative analysis of drugs in blood plasma using electrospray ionization-mass spectrometry without chromatographic separation // Khim. farm. magazine - 2007. - No. 4. - S. 161-166.

3. Karatasso Yu.O., Alyoshin S.E., Popova N.V. Quantitative analysis of prostaglandins and polyunsaturated fatty acids by mass spectrometry with electrospray ionization // Mass spectrometry. -2007. - T.4. - AT 3. - S. 173-178.

4. Kholodov L.E., Yakovlev V.P. Clinical pharmacokinetics. - M.: Medicine, 1985. - 463 p.

5. Covey T.R., Lee E.D., Henion J.D. High-speed liquid chromatography/tandem mass spectrometry for the determination of drugs in biological samples // Anal. Chem. - 1986. - Vol. 58 (12). - P. 2453-2460.

6. Conference report on analytical methods validation: bioavailability, bioequivalence and pharmacokinetic studies // J. Pharmac. sci. - 1992. - Vol.81. - P. 309-312.

7. De Long C.J., Baker P.R.S., SamuelM. et al. Molecular species composition of rat liver phospholipids by ESI-MS/ MS: The effect of chromatography//J. Lipid Res. - 2001. - Vol. 42. - P. 1959-1968.

8. Electrospray Ionization Mass Spectrometry. Ed. R. B. Cole // Wiley. - New York, 1997.

9. Han X., Yang K., Yang J. et al. Factors influencing the electrospray intrasource separation and selective ionization of glycerophospholipids // Am. soc. mass spectrom. - 2006. - Vol. 17(2). - P. 264-274.

10. Koivusalo M., Haimi P., Heikinheimo L. et al. Quantitative determination of phospholipids compositions by ESI-MS: Effects of acyl chain length, unsaturation, and lipid concentration on instrument response // J. Lipid Res. - 2001. - Vol. 42.-P. 663-672.

11. Lee M.S., Kerns E.H. LC/MS applications in drug discovery//Mass Spectrom. Rev. - 1999. - Vol. 18(3-4). - P. 187-279.

Received 05/28/10.

ANALYSIS OF DRUGS IN PHARMACOKINETIC STUDIES

D.V. Reikhart, V.V. Chistyakov

Conducted was a review of sensitive and specific analytical methods for studying the pharmacokinetics of drugs. Shown were the advantages and limitations of immune-enzyme analysis, of high performance liquid chromatography with fluorescence and mass spectrometric detection. The usage of a method in the evaluation of the pharmacokinetics of drugs in each case should be determined by the structure of the compound and the laboratory equipment.

Key words: liquid chromatography, fluorescence and mass spectrometric detection, immune-enzyme analysis, pharmacokinetics.

Page 1

One of the most important tasks of pharmaceutical chemistry is the development and improvement of methods for assessing the quality of medicines.

To establish the purity of medicinal substances, various physical, physico-chemical, chemical methods of analysis or a combination of them are used. GF offers following methods quality control of drugs.

Physical and physico-chemical methods. These include: determination of melting and solidification temperatures, as well as temperature limits of distillation; determination of density, refractive indices (refractometry), optical rotation (polarimetry); spectrophotometry - ultraviolet, infrared; photocolorimetry, emission and atomic absorption spectrometry, fluorimetry, nuclear magnetic resonance spectroscopy, mass spectrometry; chromatography - adsorption, distribution, ion-exchange, gas, high-performance liquid; electrophoresis (frontal, zonal, capillary); electrometric methods (potentiometric determination of pH, potentiometric titration, amperometric titration, voltammetry).

In addition, it is possible to use methods that are alternative to pharmacopoeial methods, which sometimes have more advanced analytical characteristics (speed, accuracy of analysis, automation). In some cases, a pharmaceutical company purchases a device that is based on a method not yet included in the Pharmacopoeia (for example, the Raman spectroscopy method - optical dichroism). Sometimes it is advisable to replace the chromatographic method with a spectrophotometric one when determining the authenticity or testing for purity. The pharmacopoeial method for determining heavy metal impurities by precipitating them in the form of sulfides or thioacetamides has a number of disadvantages. For the determination of heavy metal impurities, many manufacturers are implementing physical-chemical methods of analysis such as atomic absorption spectrometry and inductively coupled plasma atomic emission spectrometry.

An important physical constant that characterizes the authenticity and degree of purity of drugs is the melting point. A pure substance has a distinct melting point, which changes in the presence of impurities. For medicinal substances containing a certain amount of admissible impurities, the GF regulates the melting temperature range within 2 °C. But in accordance with Raoult's law (AT = iK3C, where AT is the decrease in the crystallization temperature; K3 is the cryoscopic constant; C is the concentration) at i = 1 (non-electrolyte), the value of AT cannot be the same for all substances. This is connected not only with the content of impurities, but also with the nature of the drug itself, i.e., with the value of the cryoscopic constant K3, which reflects the molar decrease in the melting point of the drug. Thus, at the same AT = 2 "C for camphor (K3 = 40) and phenol (K3 = 7.3), the mass fractions of impurities are not equal and amount to 0.76 and 2.5%, respectively.

For substances that melt with decomposition, the temperature at which the substance decomposes and a sharp change in its appearance occurs is usually indicated.

Purity criteria are also the color of the drug and / or the transparency of liquid dosage forms.

Physical constants such as the refractive index of a light beam in a solution of the test substance (refractometry) and the specific rotation due to the ability of a number of substances or their solutions to rotate the polarization plane when gaussically polarized light passes through them (polarimetry) can serve as a certain criterion for the purity of a drug. Methods for determining these constants are related to optical methods of analysis and are also used to establish the authenticity and quantitative analysis of drugs and their dosage forms.

An important criterion for the good quality of a number of drugs is their water content. A change in this indicator (especially during storage) can change the concentration of the active substance, and, consequently, the pharmacological activity and make the drug unsuitable for use.

Chemical methods. These include: qualitative reactions for authenticity, solubility, determination of volatile substances and water, determination of nitrogen content in organic compounds, titrimetric methods (acid-base titration, titration in non-aqueous solvents, complexometry), nitritemetry, acid number, saponification number, ether number, iodine number, etc.

biological methods. Biological methods of drug quality control are very diverse. Among them are tests for toxicity, sterility, microbiological purity.

Introduction

Chapter 1. Basic Principles of Pharmaceutical Analysis

1.1 Pharmaceutical analysis criteria

1.2 Errors in Pharmaceutical Analysis

1.3 General principles for testing the identity of medicinal substances

1.4 Sources and causes of poor quality of medicinal substances

1.5 General requirements for purity tests

1.6 Methods of pharmaceutical analysis and their classification

Chapter 2. Physical Methods of Analysis

2.1 Verification of physical properties or measurement of physical constants of drug substances

2.2 Setting the pH of the medium

2.3 Determination of clarity and turbidity of solutions

2.4 Estimation of chemical constants

Chapter 3. Chemical Methods of Analysis

3.1 Features of chemical methods of analysis

3.2 Gravimetric (weight) method

3.3 Titrimetric (volumetric) methods

3.4 Gasometric analysis

3.5 Quantitative elemental analysis

Chapter 4. Physical and chemical methods of analysis

4.1 Features of physicochemical methods of analysis

4.2 Optical methods

4.3 Absorption methods

4.4 Methods based on emission of radiation

4.5 Methods based on the use of a magnetic field

4.6 Electrochemical methods

4.7 Separation methods

4.8 Thermal methods of analysis

Chapter 5

5.1 Biological quality control of medicines

5.2 Microbiological control of medicinal products

List of used literature

Introduction

Pharmaceutical analysis is the science of chemical characterization and measurement of biologically active substances at all stages of production: from the control of raw materials to the assessment of the quality of the resulting medicinal substance, the study of its stability, the establishment of expiration dates and the standardization of the finished dosage form. Pharmaceutical analysis has its own specific features that distinguish it from other types of analysis. These features lie in the fact that substances of various chemical nature are subjected to analysis: inorganic, organoelement, radioactive, organic compounds from simple aliphatic to complex natural biologically active substances. The range of concentrations of analytes is extremely wide. The objects of pharmaceutical analysis are not only individual medicinal substances, but also mixtures containing a different number of components. The number of medicines is increasing every year. This necessitates the development of new methods of analysis.

The requirements for pharmaceutical analysis are high. It should be sufficiently specific and sensitive, accurate in relation to the standards stipulated by GF XI, VFS, FS and other scientific and technical documentation, carried out in short periods of time using the minimum quantities of tested drugs and reagents.

The conclusion about the quality of the medicinal product can only be made on the basis of the analysis of the sample (sample). The procedure for its selection is indicated either in a private article or in a general article of the Global Fund XI (issue 2). Sampling is carried out only from undamaged sealed and packed in accordance with the requirements of the NTD packaging units. At the same time, the requirements for precautionary measures for working with poisonous and narcotic drugs, as well as for toxicity, flammability, explosiveness, hygroscopicity and other properties of drugs, must be strictly observed. To test for compliance with the requirements of the NTD, multi-stage sampling is carried out. The number of steps is determined by the type of packaging. At the last stage (after control by appearance), a sample is taken in the amount necessary for four complete physical and chemical analyzes (if the sample is taken for controlling organizations, then for six such analyzes).

Performing a pharmacopoeial analysis allows you to establish the authenticity of the drug, its purity, to determine the quantitative content of the pharmacologically active substance or ingredients that make up the dosage form. While each of these stages has a specific purpose, they cannot be viewed in isolation. They are interrelated and complement each other. For example, melting point, solubility, pH of an aqueous solution, etc. are criteria for both authenticity and purity of a medicinal substance.

Chapter 1. Basic Principles of Pharmaceutical Analysis

1.1 Pharmaceutical analysis criteria

A measure of the sensitivity of a reaction is the limit of detection. It means the lowest content at which the presence of the determined component can be detected by this method with a given confidence level. The term "limit of detection" was introduced instead of such a concept as "discovered minimum", it is also used instead of the term "sensitivity". The sensitivity of qualitative reactions is influenced by such factors as the volumes of solutions of reacting components, concentrations of reagents, pH of the medium, temperature, duration experience.This should be taken into account when developing methods for qualitative pharmaceutical analysis.To establish the sensitivity of reactions, the absorbance index (specific or molar), established by the spectrophotometric method, is increasingly used.In chemical analysis, the sensitivity is set by the value of the limit of detection of a given reaction.Physicochemical methods are distinguished by high sensitivity The most highly sensitive are radiochemical and mass spectral methods, which allow determining 10-810-9% of the analyte, polarographic and fluorimetric methods 10-610-9%, sensitivity of spectrophotometric methods Yu-310-6%, potentiometric methods 10-2%.

The term "analysis accuracy" simultaneously includes two concepts: reproducibility and correctness of the obtained results. Reproducibility characterizes the scatter of the results of an analysis compared to the mean. Correctness reflects the difference between the actual and found content of the substance. The accuracy of the analysis for each method is different and depends on many factors: the calibration of measuring instruments, the accuracy of weighing or measuring, the experience of the analyst, etc. The accuracy of the analysis result cannot be higher than the accuracy of the least accurate measurement.

So, when calculating the results of titrimetric determinations, the least accurate figure is the number of millimeters.

Brief outline of the lecture

LV classification

Classification of drugs (continued)

Pharmaceutical analysis (analysis of drugs and drugs)

Pharmaceutical analysis (classifications)

Pharmaceutical Analysis Criteria

Pharmacopoeial analysis of drugs (general structure)

chemical name

10. Design example

11. An example of constructing the chemical name of an organic drug

12. An example of constructing the chemical name of an organic drug (2)

13. Description of the drug

14. Description of LP - polymorphism

15. Polymorphism (examples)

16. Polymorphism (examples)

17. Polymorphism (examples)

18. Polymorphism (examples)

19. Polymorphism (examples)

20. Polymorphism and bioavailability

21. Methods for the study of polymorphic forms

22. Particle size (powders, pellets)

23. Solubility

24. Solubility

25. Acid-base properties

26. Methods for determining physical constants

27. Relative density (d20)

28. Relative density

29.

30. Refractive index

31. Refractometers

32.

33. Optical rotation

34. Optical rotation

35.

36. Polarimetry (equipment)

37. Viscosity

38. Viscosity (capillary method)

39. Temperature limits of distillation

40. Melting point

41. Determination of melting point (instrumental)

42. Authenticity (methods)

43. Examples of identification reactions by functional groups

44. Examples of identification reactions by functional groups

45. Specific reactions to ions

46. ​​Specific reactions to ions

47. Specific reactions to ions

48. Specific reactions of authenticity

49.

50.

51.

52.

53.

54.

55.

56.

57. Authenticity (methods)

58. Authenticity (methods)

59. Authenticity (proof)

60. Impurities (classification)

61. Impurities

62. Weight loss on drying (gravimetric method)

63. Definition of water

64. Physical and chemical properties characterizing purity

65. Definition of ash

66. Definition of "heavy" metals

67. Residual organic solvents (classification)

68. Residual organic solvents (classification, continued)

69. Residual organic solvents

70. Residual organic solvents (analysis)

71. Specific impurities

72. Specific impurities

73. Specific impurities

74. Specific impurities

75. Associated impurities in drugs of natural origin (example)

76. Specific impurities

77. Stress tests -

78. Stress tests (conditions)

79. Quantification

Introduction

Chapter 1. Basic Principles of Pharmaceutical Analysis

46. Specific reactions to ions