An improved micromethod for vancomycin determination by high-performance liquid chromatography

A micromethod using reversed-phase high-performance liquid chromatography for the analysis of vancomycin in human serum or plasma was developed. Ristocetin was used as the internal standard. Chromatographic conditions included an amino propyl column, a mobile phase with 62% acetonitrile and 38% sodium phosphate buffer (pH 7.0), a total run time of 10 min, and ultraviolet absorbance detection at 225 nm. Multilevel calibration was found to be linear between 1.0 and 100 micrograms/ml with correlation coefficients of the calibration line slope consistently > 0.999. Recovery of vancomycin from serum was nearly complete, and no interference from commonly used drugs was observed. This procedure is simple, sensitive, rapid, precise, selective, and requires only 50 microliters of serum or plasma for completion.