[Determination of nystatin component composition using HPLC and TLC with densitometry]. / Opredelenie komponentnogo sostava nistatina metodami VEZhKh i TSKh s ispol'zovaniem densitometrii.

The component composition of nystatin produced by an improved strain of Streptomyces noursei was determined by HPLC on Milichrom chromatograph (USSR). It was shown that the antibiotic consisted of nystatins A1, A2, A3 and B and admixture substances. The data appeared to be in good agreement with the results of the complex TLC investigation, by using densitometry. The component composition of the samples was evidenced by SIEAP mass spectrometry. Physiochemical and biological characteristics of separate components are presented.

[Various ways of standardizing and unifying biological methods of determining the activity of antibiotics]. / Nekotorye puti standartizatsii i unifikatsii biologicheskikh metodov opredeleniia aktivnosti antibiotikov.

It was shown possible to use nutrient media containing only salt components and agar-agar for determination of biological activity of tetracyclines (tetracycline, morphocycline, oxytetracycline and chlortetracycline), erythromycin and oleandomycin. A uniform nutrient medium containing ammonium chloride, trisubstituted sodium citrate, disubstituted sodium phosphate and agar-agar was developed. Glucose is added to this medium simultaneously with the test microbe, B. subtilis ATCC 6633. The medium of the above composition provided readily reproducible results.

[Growth of test microorganisms used in determining antibiotic activity on synthetic nutrient media]. / Rost test-mikroorganizmov, ispol'zuemykh pri opredelenii aktivnosti antibiotikov, na sinteticheskikh pitatel'nykh sredakh.

The growth of gram-negative sporulating bacteria and yeast-like fungi used in a microbilogical assay of antibiotic activity was studied on solid synthetic media of simple composition. Their reproduction with the microbial growth of different density was shown to be possible on media containing available and strictly standardized components, such as salts, glucose and disubstituted sodium phosphate. The cultures tested were not similar by their growth requirements.

[Effect of the extraction methods and drug form components on the determination of gramicidin C in buccal tablets]. / Vliianie metodov ékstraktsii i komponentov lekarstvenoi formy na oppredelenie gramitsidina c v zashchechnykh tabletkakh.

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.

[Effect of the cultivation conditions of Candida species yeast-like fungi on their sensitivity to levorin]. / Vliianie uslovii kul'tivirovaniia drozhzhepodobnykh gribov roda Candida na ikh chuvstvitel'nost' k levorinu

The effect of levorin on yeast-like fungi under (different) cultivation conditions was studied. It was shown that the medium composition and incubation temperature affected the results of determination of the test-culture sensitivity to levorin. There was correlation between the time of the population lag-phase and the critical time of the zone formation and these values depended on the temperature of the test-microbe vegetation. Strain 037 of C. utilis was more sensitive to levorin and had a longer lag-phase as compared to the other species of the yeast-like fungi, which provided favourable conditions for formation of the growth inhibition zones.