Development and validation of a sensitive analytical method for the simultaneous determination of buprenorphine and norbuprenorphine in human plasma.

A sensitive, specific, and robust capillary gas chromatography-mass spectrometry method has been developed and validated for simultaneous determination of buprenorphine and its active metabolite, norbuprenorphine, in human plasma. Sample preparation involved a clean-up procedure using a Bond Elut Certify cartridge followed by derivatization with pentafluoropropionic anhydride. Separation was carried out on a HP-1 fused silica capillary column using helium as the carrier gas. Selected ion monitoring was used in the electron impact mode. Excellent linearity was found between 0.10 and 20.0 ng/ml with a limit of quantitation of 0.05 and 0.10 ng/ml for buprenorphine and norbuprenorphine, respectively. Interday and intraday assay precisions (%CV) and accuracies were within 15.0% for buprenorphine and norbuprenorphine, respectively. Recoveries were quantitative and concentration-independent. This method will be applied to pharmacokinetic/pharmacodynamic/bioequivalence studies of buprenorphine in humans.