RU2146524C1 - Method of assay of drugs - derivatives of n-glycoside structure using standard specimen - Google Patents

Abstract

FIELD: medicine, analytical chemistry. SUBSTANCE: method involves the use of 0.1 M hydrochloric acid solution as the solvent for preparing solutions to be tested and potassium bichromate solution as standard for assay of adenosine, phosphaden and riboxin. Then solutions of the substance to be determined of N-glycoside structure and standard specimen are analyzed by spectrophotometry method at wavelength 258 nm for adenosine and phosphaden and at 249 nm for riboxin. Scaling factor is introduced to the formula for measurement of quantitative determination of substances to be analyzed. Invention can be used in control-analytical laboratories for standardization and quality control of drugs. EFFECT: improved reproducibility of assay data, decreased errors.

Description

 The invention relates to medicine and can be used in control and analytical laboratories for standardization and quality control of medicines.

 Currently, the problem of providing the population with effective high-quality medicines is especially acute. One of the important factors contributing to the improvement of the quality of medicines is the systematic increase in the effectiveness of methods for their control and standardization.

 Visible and UV spectrophotometry is one of the most widely used methods in drug analysis. The objects of this study are promising drugs used to treat vascular lesions of the brain - derivatives of purine of the N-glycoside structure - adenosine, phosphaden and riboxin.

 A known method of spectrophotometric determination of adenosine and phosphaden, which consists in the preparation of aqueous solutions of the tested substances with their subsequent photometry at wavelengths of 259.5 and 257 nm, respectively, and calculation of the results using the values of molar and specific absorption for adenosine and phosphaden, respectively / TU 64-01 -12-10-89 "Adenosine 1.5-aqueous for adenosine triphosphoric acid", FS 42-1960-83 "Phosphaden".

 The closest and adopted by us as a prototype is a method for determining riboxin by preparing aqueous solutions of the test substance and a standard riboxin sample, respectively, followed by spectrophotometry at a wavelength of 249 nm and calculating the results using a standard riboxin sample / FS 42-2069-83 "Riboxin" /.

 The spectrophotometric method for the quantitative determination of phosphaden and adenosine recommended by normative and technical documentation is not sufficiently reproducible on different devices, since the specific one is used to calculate the phosphaden content and the molar absorption indices are used for adenosine. This is the reason for the errors of their spectrophotometric determination, reaching ± 6.1%.

 To eliminate the calibration error and improve the accuracy of spectrophotometric analysis using standard samples. However, the production of standard samples of adenosine, phosphaden, and also riboxin is expensive. Therefore, the method of determination using such standard samples will be little accessible to many laboratories.

 The technical result of the proposed method is to increase the reproducibility of the determination results and reduce the analysis error.

 The technical result is achieved by preparing a solution of the analyte and a standard sample of properties, followed by spectrophotometry and calculation of the results.

 New in achieving the technical result is that a 0.1 M hydrochloric acid solution is used as a solvent for the preparation of test solutions.

 New is the fact that potassium dichromate is used as a standard sample by introducing a conversion factor in the formula for calculating the results.

 The studied substances change the absorption spectrum depending on the pH of the medium. Based on the values of the ionization constants and properties of adenosine, phosphaden, and riboxin, the authors proved that the 0.1 M hydrochloric acid solution is the optimal solvent for their spectrophotometric determination. The optimal solvent provides stabilization of the tested solutions, which increases the reproducibility of the determination results and reduces the analysis errors.

 In this solvent, the absorption spectra of adenosine and phosphaden are characterized by a maximum absorption at 258 nm, riboxin - at 249 nm.

 Based on the dependence established by the authors, according to which substances can be used as standard property samples for which the interval between the analytical wavelength and the absorption maximum of this standard sample does not exceed half the half width of its absorption band, potassium dichromate is used as a standard sample in the proposed method, so as the optimal absorption regions in which it can be used as a standard sample of properties 249-262 and 340-359 nm. Potassium dichromate is commercially available as a chemically pure substance, there is GOST that regulates its quality, and a solution of potassium dichromate is stable in optimal solvents for a long time. The use of potassium dichromate in the proposed method reduces the analysis error.

 Comparative analysis shows that the claimed technical solution is characterized in that a 0.1 M hydrochloric acid solution is used as a solvent for the preparation of test solutions, and potassium dichromate is used as a standard sample by introducing a conversion factor in the formula for calculating the results, which meets the criteria of the invention " novelty".

 A new set of features provides an increase in the reproducibility of the determination result, a decrease in the analysis error, and also allows to reduce the cost of analysis, which meets the criterion of "industrial applicability".

 In the analysis of known solutions, it was revealed that they lack information on the influence of distinguishing features on the achievement of the technical result, therefore, the invention meets the criterion of "inventive step".

 The method is as follows.

 A solution of a standard sample of potassium dichromate is prepared for the analysis of adenosine, phosphaden, riboxin. To do this, the exact mass of potassium dichromate / 0.1500 g / is placed in a volumetric flask with a capacity of 100 ml, dissolved in a 0.1 M hydrochloric acid solution and adjusted to the mark with the same solvent, mixed. 1 ml of the prepared solution of potassium dichromate is placed in a volumetric flask with a capacity of 50 ml and adjusted with a 0.1 M hydrochloric acid solution to the mark, mixed. Then adenosine, phosphaden and riboxin are quantitated in the substance. To do this, the exact mass of the drug / 0.0500 g / is placed in a 100 ml volumetric flask, dissolved in hot water, adjusted to the mark with this water and mixed. The solution is cooled. 1 ml of the prepared solution is transferred to a volumetric flask with a capacity of 50 ml and adjusted with a 0.1 M hydrochloric acid solution to the mark, mixed. The optical density of the test solution is measured at a wavelength of 258 nm / for adenosine and phosphaden / and at 249 nm / for riboxin / relative to a 0.1 M hydrochloric acid solution on a spectrophotometer in cuvettes with a working layer length of 10 mm. In parallel, the optical density of a solution of a standard sample of potassium dichromate is measured at a wavelength of 258 nm / in the analysis of adenosine and phosphaden / and at a wavelength of 249 nm / in the analysis of riboxin / relative to a 0.1 M hydrochloric acid solution on a spectrophotometer in a cuvette with a working layer 10 mm long .

где Д_х и Д_ст - оптические плотности определяемого вещества и стандартного образца соответственно;
a_х и a_ст - точные навески определяемого вещества и стандартного образца соответственно;
100 - коэффициент для пересчета в проценты;
K_пер. - коэффициент пересчета, который рассчитывают следующим образом:

где E $\genfrac{}{}{0ex}{}{\text{1\%}}{\text{1см}}$ _с.с. - удельный показатель поглощения стандартного образца дихромата калия при максимуме поглощения препарата;
E $\genfrac{}{}{0ex}{}{\text{1\%}}{\text{1см}}$ _с.в. - удельный показатель поглощения стандартного образца лекарственного вещества при максимуме поглощения /определяются при разработке методики и могут уточняться для каждого прибора, если он не откалиброван/;
K_пер. для аденозина - 0,264;
K_пер. для фосфадена - 0,344;
K_пер. для рибоксина - 0,360.The calculation of the results of the quantitative determination is carried out according to the formula:

where D _x and D _article - the optical density of the analyte and the standard sample, respectively;
a _x and a _st - exact weights of the analyte and the standard sample, respectively;
100 - coefficient for conversion to percent;
K _per. - conversion factor, which is calculated as follows:

where e $\genfrac{}{}{0ex}{}{\text{1\%}}{\text{1cm}}$ _s.s - specific absorption rate of a standard sample of potassium dichromate with a maximum absorption of the drug;
E $\genfrac{}{}{0ex}{}{\text{1\%}}{\text{1cm}}$ _sv - the specific absorption rate of a standard sample of a medicinal substance with a maximum absorption / are determined during the development of the methodology and can be specified for each device if it is not calibrated /;
K _per. for adenosine - 0.264;
K _per. for phosphaden - 0.344;
K _per. for riboxin, 0.360.

 The content of adenosine should be at least 98.0%, phosphaden in terms of dry matter should be at least 98.0% and not more than 102.0%, riboxin in terms of dry matter should be at least 96.0% and no more 102.0%.

 The proposed method is illustrated by the following examples. Prepare solutions of the test sample and standard substance as described above. The optical densities of the prepared solutions are measured on a spectrophotometer. Next, the results are calculated according to the formula using the conversion factor.

S = 0,50,

ε_α= 0,47 /P = 95%/, A% = 0,47.When determining phosphaden, the following results were obtained: D _x = 0.426, D _Art. = 0.443, a _x = 0.05225, a _st. = 0.14980, humidity 4.79%, X = 99.6%. When n = 6,

S = 0.50,

ε _α = 0.47 / P = 95% /, A% = 0.47.

S = 0,56,

ε_α= 0,50 /P = 95%/, A% = 0,50.When determining adenosine, the following results were obtained: D _x = 0.620, D _Art. = 0.453, a _x = 0.05626, a _st. = 0.15595, X = 100.2%. When n = 6,

S = 0.56,

ε _α = 0.50 / P = 95% /, A% = 0.50.

S = 0,37,

ε_α= 0,34 /P = 95%/, A% = 0,34.When determining riboxin, the following results were obtained: D _x = 0.396, D _Art. = 0.432, a _x = 0.0500, a _st. = 0.1505, X = 100.0%. When n = 6,

S = 0.37,

ε _α = 0.34 / P = 95% /, A% = 0.34.

 These examples confirm that the content of adenosine, phosphaden and riboxin meets the requirements of the regulatory document.

 The proposed method using a standard sample of potassium dichromate turned out to be optimal for the quantitative determination of phosphaden and riboxin in tablets and solution for injection, and also made it possible to establish with sufficient accuracy the dosage uniformity of phosphaden tablets and to control the dissolution test of phosphaden and riboxin tablets.

 The methods for the quantitative determination of phosphaden and riboxin in dosage forms differ from the methods for the quantitative determination of phosphaden and riboxin in a substance only by the preparation of the test solution.

 For the quantitative determination of phosphaden in 0.05 g tablets and riboxin in 0.2 g coated tablets, take the exact powder mass / 0.2500 g / crushed phosphaden tablets or one riboxin tablet, powdered, and quantitatively transfer from Using hot water in volumetric flasks with a capacity of 100 ml and 200 ml, respectively, shake for 15 minutes, bring the solution volume with the same water to the mark, mix, cool and filter through a paper filter, discarding the first 15 - 20 ml of the filtrate. 1 ml of the obtained filtrate is transferred into volumetric flasks with a capacity of 50 ml and 100 ml, respectively, and the solution volume is adjusted with a 0.1 M hydrochloric acid solution to the mark, mixed.

 The content of phosphaden in tablets of 0.05 g should be 0.045-0.055 g, riboxin in tablets of 0.2 g should be 0.19 - 0.21 g.

 The quantitative determination of riboxin and phosphaden in tablets is illustrated by the following examples.

When analyzing riboxin tablets of 0.2 g, the results are obtained: D _x = 0.452, D _Art. = 0.456, a _st. = 0.0515, X = 0.2042.

When analyzing phosphaden tablets of 0.05 g, the results are obtained: D _x = 0.419, D _Art. = 0.24, a _x = 0.24835, a _st. = 0.1042, P _cf. = 0.2083, X = 0.0525.

 These examples confirm that the content of riboxin and phosphaden in tablets meets the requirements of the regulatory document.

 For the quantitative determination of riboxin in a 2% solution for injection and phosphaden in a 2% solution for injection, the volume of the dosage form 5 ml and 1 ml, respectively, is placed in a volumetric flask with a capacity of 100 ml and the solution volume is adjusted with a 0.1 M hydrochloric acid solution to the mark, stirred .

 The content of riboxin and phosphaden in 1 ml of the drug in grams / X / should be 0.019-0.021.

When analyzing riboxin in a 2% solution for injection, the results were obtained: D _x = 0.407, D _Art. = 0.429, a _Art. = 0.1500, X = 0.0205.

When analyzing phosphaden in a 2% solution for injection, the results were obtained: D _x = 0.431, D _Art. = 0.414, a _st. = 0.14415, X = 0.0206.

 To determine the uniformity of dosage of 0.05 g phosphaden tablets, one tablet is placed in a 100 ml volumetric flask and dissolved in hot water, adjusted to the mark with the same water, mixed, cooled and filtered. 1 ml of the filtrate is placed in a volumetric flask with a capacity of 50 ml and the solution volume is adjusted with a 0.1 M hydrochloric acid solution to the mark.

 Permissible deviation from the nominal value is not more than ± 15% for ten analyzed tablets.

 When analyzing ten tablets of phosphaden, 0.05 g each received a maximum deviation from the nominal content of + 4.2 and -5.2%.

 To control the dissolution test, the riboxin and phosphaden tablets were taken as the basis for a unified methodology / GF XI ed., S. 159-160 /. A 0.1 M hydrochloric acid solution was used as a dissolution medium, the dissolution time for riboxin tablets was set to 45 minutes, and for phosphaden tablets, 25 minutes.

 In the analysis of 0.2 g riboxin tablets and 0.05 g phosphaden tablets, 5 ml of the filtrate is placed in a volumetric flask with a capacity of 100 ml and 25 ml, respectively, the solution volume is adjusted to a mark with a 0.1 M hydrochloric acid solution and stirred.

 According to the Global Fund XI ed. S. 159-160, at least 75% of the active substance from the content in the dosage form should go into the dissolution medium.

 In the analysis of tablets of riboxin 0.2 g each, the release of the active substance was 82.5; 92.7; 91.6; 91.3; 92.5% for five tablets, respectively.

 When analyzing phosphaden tablets of 0.05 g, the release of the active substance was 92.3; 89.4; 94.7; 95.6; 96.8% for five tablets, respectively.

 Thus, the proposed method for the determination of drugs of purine derivatives of N-glycoside structure using a standard sample of properties allows to increase the reproducibility of the determination results, reduce the analysis error and reduce its cost.

Claims (1)

 A method for the determination of drugs of purine derivatives of an N-glycoside structure using a standard sample of properties by preparing solutions of the analyte and a standard sample of properties, followed by spectrophotometry and calculation of the results, characterized in that a 0.1 M hydrochloric solution is used as a solvent for the preparation of test solutions acid, and as a standard sample - potassium dichromate, introducing a conversion factor in the formula for calculating the results.