High performance liquid chromatographic assay of neothramycin in biological fluids

A high performance liquid chromatographic method for quantitative determination of neothramycin in plasma was developed. The procedure involves pretreatments for the removal of endogenous materials in plasma samples and separation on a reversed phase column. The antibiotic was monitored with a fluorescence detector and confirmed by a specific sulfite adduct shift of retention time. A linear response for serum samples containing neothramycin ranging from 50 to 500 ng/ml was obtained. The sensitivity of this method was sufficient to measure neothramycin in human plasma for 120 minutes after a 24 mg/m2 (body surface area) intravenous injection.