Biomedical subjects

N B Dzegilenko

Publications and source records attributed to N B Dzegilenko.

8 recordsLinked to original sources

PubMed1978

[Electron microscopic study of active and inactive variants of Proactinomyces (Nocardia) mediterranei, a producer of rifamycin B].

Four mutants of Proactinomyces (Nocardia) mediterranei, an organism producing rifamycin B were subjected to electron microscopic investigation. The mutants differed in the biosynthetic activity. The investigation showed correlation between the length of the hyphal fragments of the over-substrate mycelium and the level of the organism activity. The study of the fine structure of the mycelium revealed changes in the structure of the cell wall, character of the nuclear material and hyphae vacuolization.

Genetic Variation↗

PubMed1978

[Quantitative determination of the phenolic ester of phenylmalonic acid by an IR spectroscopy method].

A quantitative method was developed for determination of phenyl ether of phenylmalonic acid (I) in the presence of phenol. The method is based on measurement of the optic density of the characteristic absorption bands of I at 1133 and 1770 cm-1 of IR-spectrum. Absorption of I at the above frequencies responded to Ber's law. Determination of I (solution in methylen chloride) was carried out on a standard curve in accordance with equation y : bx for the both frequencies. The value of constants b of the direct regressions for the frequencies of 1133 and 1770 cm-1 were determined with relative errtor of +/- 1.2 and 2.3 per cent respectively. The correlation coefficients were equal to 0.98 and 0.95.

Chromatography, Thin Layer↗

PubMed1977

[Spectrophotometric determination of rifampicin S in the presence of rifampicin O].

The limits of the use of the methods of direct photometric and differential spectrophotometric determination of rifamycin S containing rifamycin O as an admixture were discussed. The method of direct photometry did not provide determination of rifamycin S in the presence of rifamycin O since instability of the latter under the analysis conditions. A possibility of using the differential-spectrophotometric method for determination of rifamycin S in the presence of not more than 5 per cent of rifamycin O was shown.

Buffers↗

PubMed1976

[Quantitative determination of 7-phenoxyacetamidodesacetoxycephalosporanic acid].

7-Phenoxyacetamidodesacetoxycephalosporanic acid, an intermediate product in synthesis of cephalexin, was prepared by oxydation of phenoxymethylpenicillin into the respective sulphoxide and transformation of the latter. The UV-spectra of the reaction products were studied. A quantitative method is proposed for determination of 7-phenoxyacetamidodesacetoxycephalosporanic acid in the finished products based on estimation os the coefficient of specific extinction of the ethanol solutions at a wave length of 268 um in the UV-spectrum region in combination with semiquantitative estimation of the admixtures with the method of thin-layer chromatography.

Cephalexin↗

PubMed1976

[Determination of rifamycin B activity in culture liquids and in preparations with varying degrees of purity].

A possibility of using the biological method of rifamycin B activity determination in the fermentation broth and dry preparations of various purity levels was studied. It was found that the biological method was useful only for determination of rifamycin B activity in preparations containing not less than 850 gamma/mg of the main product. When the activity of rifamycin B was determined in the fermentation broth and crude preparations containing less than 800 gamma/mg of the main product, the results of the biological assay were always higher as compared to those of spectrophotometrical estimation. It was accounted for the effect of other rifamycin types possessing high biological activity.

Agar↗

PubMed1976

[Quantitative determination of anhydroleandomycin and glycol in oleandomycin phosphate].

A spectrophotometric method for determination of inactive admixtures in oleandomycin phosphate-anhydrooleandomycin was developed. The method was based on measuring optical density of methanol solutions of oleandomycin and its admixtures at a wave length of 235 nm of UV-spectrum. The minimun detectable amount was 0.5 per cent. A method of thin-layer chromatography in a buffered fixed layer was developed for determination of the 2nd inactive admixture, i.e. glycole. The chromatogrammes were developed with xanthydrol. The minimum detectable amount was 3 mug.

Anhydrides↗

PubMed1976

[Chromatographic control of the process of rifamycin B isolation and purification].

A method of chromatography in a thin layer of Silica Cel No. 2 was developed for rifamicin B, rifamicin complex and some admixtures. Extracts of rifamicin B in an organic solvent, aqueous buffer reextracts and dry preparations of rifamicin B were analyzed with the above method. A half-quantitative chromatographic procedure for estimation of the main admixture in dry preparations was proposed.

Buffers↗

PubMed1975

[Quantitative method for determining variamycin].

A quantitative spectrophotmetric method for the assay of variamycin in commercial samples was developed. It was based on the measurement of the optical density of variamycin solutions in 0.01 N hydrochloric acid at a UV spectrum wave length of 412 nm. A method of thin-layer chromatography for a semi-quantitative estimation of tetraside, the main admixture of variamycin was devised. On storage for 18 months the content of variamycin in the preparations did not change as compared to that at the moment of the drug manufacturing and the amount of tetraside in 18 months did not exceed 2 per cent.

Antibiotics, Antineoplastic↗