RESUMEN
Optimal conditions for separation of rifampicin in a thin layer of a sorbent were developed. This allowed one to study the quantitative content of the admixtures of the related substances in the eluates of the respective spots on chromatograms. The possible use of both the spectrophotometric method and the biological agar diffusion method for testing the eluates was shown. The method of phase solubility also provided objective characterization of the purity levels of market rifampicin. A significant increase in the level of the admixtures of the related substances in rifampicin in 150 mg capsules was found on their storage.
Asunto(s)
Contaminación de Medicamentos , Rifampin/análisis , Cápsulas , Cromatografía en Capa Delgada/métodos , Estabilidad de Medicamentos , Almacenaje de Medicamentos , Quinonas/análisis , Espectrofotometría/métodosRESUMEN
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.
Asunto(s)
Estreptomicina/normas , Bacillus cereus/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Estándares de Referencia , Soluciones , Estreptomicina/farmacología , Organización Mundial de la SaludRESUMEN
The properties of tetracycline hydrochloride tablets from various manufacturers were studied. Differences depending on the character of the coating were found: the film-coated tablets differed from dragee by a shorter period of the antibiotic transfer to solution, better disintegration, lower content of anhydroderivatives and higher stability. Correlation between the rate of tetracycline transfer to solution in vitro and the antibiotic absorption into blood on the oral use of the tablets was shown.
Asunto(s)
Tetraciclina/metabolismo , Disponibilidad Biológica , Cromatografía en Gel , Densitometría , Humanos , Técnicas In Vitro , Absorción Intestinal/efectos de los fármacos , Pronóstico , Solubilidad , Espectrofotometría , Comprimidos , Comprimidos Recubiertos , Tetraciclina/análisis , Factores de TiempoRESUMEN
The content of admixtures in tetracycline stored under different conditions was determined with chromatographic and spectrophotometric methods. Biological activity, toxicity and colour of the drugs was tested. The changes in teh colour of tetracycline most pronounced on its storage at a temperature of 37 degrees C and elevated humidity were not accompanied by an increase in the content of anhydrotetracyclines. In parallel with the changes in the colour of tetracycline, the loss of its biological activity up to 30 per cent and increased toxicity were registered. The LD50 decreased by 40 per cent as compared to the initial level. Simultaneously an additional spot with high chromatographic mobility (Rf 0.98--1.0) was detected on thin-layer chromatograms. It was shown that the processes of tetracycline degradation resulting in marked darkening of the drug colour were not accompanied by an increase in the content of anhydro admixtures. They were probably the result of accumulation of other products which are as highly toxic and low active as the anhydroderivatives of tetracycline.
Asunto(s)
Contaminación de Medicamentos , Tetraciclina/aislamiento & purificación , Animales , Almacenaje de Medicamentos , Dosificación Letal Mediana , Ratones , Polvos , Comprimidos , Temperatura , Tetraciclina/análisis , Tetraciclina/toxicidad , Factores de TiempoRESUMEN
The results and conditions of separation and quantitative determination of the admixtures of epi- and anhydro-derivatives of tetracycline in its market products were compared and analyzed using the following chromatographic methods: chromatography in a thin layer of a sorbent in 2 modifications, circular paper chromatography, chromatography on a column of gel Sephadex G-25. The comparison of the results of the study provided recommendation of the column chromatography with gel Sephadex G-25 for separate or summation quantitative determination of 4-epitetracycline. The method of chromatography in a thin layer of a sorbent may be successfully used for semiquantitative determination of the admixture levels in tetracycline market drugs.
Asunto(s)
Tetraciclina/análisis , Cromatografía en Gel/métodos , Cromatografía en Papel/métodos , Cromatografía en Capa Delgada/métodos , Densitometría , Contaminación de Medicamentos , Tetraciclinas/análisisRESUMEN
Alfa- and delta forms of cephalosporin were compared. Biological activity, lantimicrobial spectrum and innocuousness of the forms and their physico-chemical properties were investigated with the methods of infrared and ultraviolet spectrophotometry and derivatography. No significant differences in the biological properties of alfa- and delta forms of cephalosporin were found. However, the ingrared spectrum of the delta-form was indicative of higher stability of its molecule, which was confirmed by higher thermostability of delta-cephalosporin.