Development and validation of a selective and rapid LC-MS-MS method for the quantification of abacavir in human plasma.

A simple, precise, and rapid liquid chromatography-tandem mass spectrometry method is developed and validated for the quantification of abacavir, a nucleoside reverse transcriptase inhibitor. Abacavir and granisetron (internal standard) were isolated from 100 muL human plasma by liquid-liquid extraction in ethyl acetate and dichloromethane (90:10, v/v). The chromatographic separation is achieved on Gemini C(18) analytical column (150 mm x 4.6mm, 5-mum particle size) under isocratic conditions at a flow rate of 1.0 mL/min. The parent --> product ion transitions for abacavir (m/z 287.2-->191.2) and internal standard (m/z 313.1-->138.2) were monitored on a triple quadrupole mass spectrometer operating in the multiple reaction monitoring (MRM) and positive ion mode. The linearity of the method for abacavir is established in the range of 29.8-9318 ng/mL with an analysis time of 2.0 min. Acceptable precision and accuracy were obtained for concentrations over the standard curves studied. The mean recovery and process efficiency of analyte obtained at three quality control levels was 86.8% and 87.9%, respectively. The application of this method for routine measurement of plasma abacavir concentration is demonstrated by a pharmacokinetic and/or bioequivalence study conducted in 28 healthy volunteers for a 300 mg tablet formulation under fasting condition.