Buprenorphine and norbuprenorphine determination in mice plasma and brain by gas chromatography-mass spectrometry.

A gas chromatography tandem mass spectrometry method for quantification of buprenorphine (BUP) and norbuprenorphine (NBUP) in brain and plasma samples from mice was developed and validated. Analytes were extracted from the brain or plasma by solid phase extraction and quantified within 20 minutes. Calibration was achieved by linear regression with a 1/x weighting factor and d4-buprenorphine internal standard. All products were linear from 1 to 2000 ng/mL with a correlation of determination >0.99. Assay accuracy and precision of back-calculated standards were within ±10%. The lower limit of quantification for both BUP and NBUP from the brain and plasma was 1 ng/mL. This sensitive and specific method can be used for the investigation of BUP mechanism of action and clinical profile.