Rapid and specific method for the determination of vancomycin in plasma by high-performance liquid chromatography on an aminopropyl column

A high-performance liquid chromatographic method has been developed for the quantitative analysis of vancomycin in plasma. The method involves protein precipitation with acetonitrile, followed by normal-phase chromatography on an aminopropyl column. The clear supernatant was injected after centrifugation, and the eluent was monitored at 240 nm. No interference was found either with endogenous substances or with many currently used drugs, indicating a good selectivity for the procedure. The standard curve was linear between 0.1 and 100 micrograms/ml, and the detection limit was 0.01 microgram/ml of plasma. The mean intra- and inter-assay coefficients of variation were 2.4 and 4.0%, respectively, in the 10-50 micrograms/ml range. Application of the method to the study of vancomycin pharmacokinetics in a rabbit after a single intravenous dose is also reported.