An LC-MS/MS method to determine vancomycin in plasma (total and unbound), urine and renal replacement therapy effluent.

Aim: Critical illness and medical interventions, such as renal replacement therapy, can cause changes to vancomycin pharmacokinetics and lead to suboptimal dosing. To comprehensively characterize vancomycin pharmacokinetic a method must measure vancomycin in a range of clinical matrices. Results: A LC-MS/MS method was developed using hydrophilic interaction liquid chromatography and microsample volumes, where possible. For all matrices, the linear concentration range was 1-100 mu g/ml, interassay accuracy and precision was within 15%, and recovery above 80%. No matrix effects were observed. Calibration equivalence may be applied for some matrix combinations. Conclusion: A method for the analysis of vancomycin in plasma (total, unbound), urine and renal replacement therapy effluent, suitable for use in any patient pharmacokinetic study, has been developed and validated.