[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.