[A method of quantitative analysis of gentamicin sulfate]

A procedure for quantitative assay of gentamicin sulfate was developed. It is based on formation of an ionic associate with bromothymol blue followed by chloroform extraction and the photometric determination at 420-422 nm. The relative error does not exceed 0.94 and 0.98 per cent in regard to the substance and its dosage form (gynecological suppositories), respectively. Optimal conditions for the assay were elaborated i.e. the ratio of the reagent and extraction agent, the time and the number of the extractions and pH of the medium. The process obeys to the main law of light absorption within the concentration of gentamicin sulfate in aqueous solution equal to 8-128 micrograms/ml.