Biomedical subjects
Publications and source records attributed to V M Grigor'eva.
Gel diffusion regularities with respect to neomycin sulfate substances differing in their composition and the antibiotic separate components were studied on nutrient media of diverse composition. Optimal conditions for standardization of neomycin sulfate antimicrobial activity with using the agar diffusion method and synthetic medium are determined.
Sensitivity of a E. coli strain and commercial colibacterins prepared with its use to 18 antibiotics was tested. The MIC was determined by the method of serial dilutions. It was shown that the strain and colibacterins were sensitive to 9 antibiotics and resistant to the others.
It was shown that a nutrient medium containing only salt components except agar-agar could be used for assay of the biological activity of heliomycin. The optimal results were observed on the medium containing ammonium chloride, urea, disubstituted sodium phosphate, glucose and agar-agar. The medium provided satisfactory growth of Bac. subtilis ATCC 6633 as the test culture and formation of clear inhibition growth zones of the sufficient size. The medium is standard and its use allows obtaining reproducible results in assay of the heliomycin biological activity.
The characteristic features of determination of the biological activity of neomycin and its separate components A, B and C were studied. Different sensitivity of 5 test microbes to neomycins A, B and C was observed. Bac. subtilis ATCC 6633 and Bac. cereus, var. myc. 537 were the most sensitive to neomycin A. Sar. lutea were not sensitive to neomycins A and C. The diffusion capacity of neomycin A was shown to be different from that of neomycins B and C. Even minute admixtures of neomycin A in the preparations of neomycin significantly changes the dose-response curves and affected the results of the biological activity determination.
The main principles in preparation of national standards of the antibiotics manufacture in the USSR are compared with those of the World Health Organization. The characteristics of preparing standards of mono- and multicomponent antibiotics, as well as the requirements for optimal packing of the standards are presented.
The possibility of using available dry nutrient media Nos. 5 to 12 in assays of antibiotic biological activity with the agar diffusions method was studied with respect to benzylpenicillin, gramicidin S, kanamycin sulfate, kanamycin B, oleandomycin, novobiocin, tetracycline and erythromycin. The dry media were used instead of the respective media prepared with meat hydrolyzate. Optimal conditions of the assays on such media were determined.
Sensitivity of industrial strains and market preparations, such as bifidumbacterin and lactobacterin was studied with respect to 19 antibiotics. The MIC was determined with the method of serial dilutions. It was shown that bifidumbacteria and lactobacteria were either highly sensitive or markedly resistant to the antibiotics.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The activity of the third International Standard of streptomycin was determined to be equal to 755 IU/mg with the use of accurately weighed amounts of streptomycin and 78037 IU with the use of streptomycin ampoules. The Standardization Center of the WHO decided to use the whole content of the ampoule of the Third International Standard of streptomycin, the activity of which is determined to be equal to 78500 IU per an ampoule.
Possible use of the dry nutrient medium manufactured in the USSR for the assay of aminoglycoside antibiotic activity with the agar diffusion method was studied. The optimal conditions for the antibiotic activity assay on this medium were developed. The dry nutrient medium may be used for the activity assay of the aminoglycoside antibiotics, i. e. streptomycin sulfate, dihydrostreptomycin sulfate, neomycin sulfate, monomycin and gentamicin sulfate.
The effect of solvents, extraction procedures and separate components of the troche mass on the results of biological activity determination of gramicidin S with the agar-diffusion method was studied. It was found that irrespective of the solvent and the number of extractions only 76--81 per cent of the antibiotic were determined in the troches. Fruit essence and sugar had a significant effect on the results of gramicidin S biological activity determination as compared to the other components of the dosage form. When accessory substances included in the troches were added to the standard solution, the values of their biological activity were close to the calculated ones.
The experiments showed that the method of direct plating of tetracycline tablet suspensions on solid nutrient media containing magnesium sulfate may be used for determination of microbial contamination. The method provided determination of both the antibiotic resistant and the antibiotic sensitive organisms which may be present in the drug. Dilution of the basic suspensions increased the probability of the microbe detection in the tablets.
The efficiency of 3 variants of the method for determination of microbial flora was compared on the injection preparation of potassium benzylpenicillin artificially infected with Staph. aureus 209P and the spores of Bac. subtilis ATCC 6633 in different doses and with different amounts of the preparation in the vials. The procedure of the preparation dissolution in the vial with the thioglycol medium containing penicillinase proved to be most effective. The microbe detection amounted to 100 per cent. The procedure was less labour- and time-consuming since addition of penicillinase to each vial with the thioglycol medium was excluded. The risk of the medium occasional infection with microbial flora during the assay was decreased.
A method for qualitative and quantitative investigation of rubomycin composition was developed. It was based on chromatographic separation of the antibiotic components in a thin layer of silicic acid followed by their elution and spectrophotometric determination. An additional component of rubomycin found in the therapeutic preparations and the conditions of its formation were studied. Fifteen different lots of rubomycin were assayed and the requirements for the limits of the admixtures in the antibiotic therapeutic preparations were determined.
During membrane filtration antibiotics belonging to different chemical groups are strictly absorbed on the filters. When the filters are put into liquid thioglycol medium, the residual amounts of the antibiotics on the filters did not prevent the growth of sensitive microflora experimentally added to the drug. When the filter was put onto solid nutrient medium, only resistant forms of the microbes grew as a rule on its surface, the amount of the grown microbes being 26--43 per cent of the added one. The sensitive microbes grew only in the amount of 0.3--1.3 per cent. Subsequently the residues of the antibiotic adsorbed on the filter inhibited the growth of the sensitive and partially resistant microflora.
It was shown that the residual amounts of tetracyclines adsorbed on membrane filters may be inactivated by addition of 2M magnesium sulphate solution to the agar for placing the filters after filtration. The antibiotic inactivation increases the possibilities of the test for antibiotic sensitivity of the microflora present in the drugs and may be used in determination of microbial dissmination of non-injection tetracyclines.
Explore the source record for details and available documents.