The glycopeptide vancomycin is a broad spectrum antibiotic for gram positive bacteria, administered intravenously for systemic infections. To accurately assess the efficacy of dosing regimes and to study the pharmacokinetics, vancomycin should be quantified from plasma.

Bioanalysis of vancomycin often utilizes an acid precipitation, which dilutes the sample, limits the specificity, and offers poor recovery (< 20%). Sample preparation via solid phase extraction (SPE) offers a clean and specific sample preparation technique. Several SPE media and various internal standards were investigated to obtain optimal recovery of both the analyte and the internal standard.

Here we report an accurate and precise LC/MS/MS assay with > 80% recovery for the determination of vancomycin from rat plasma.