Quantitative determination of abacavir (1592U89), a novel nucleoside reverse transcriptase inhibitor, in human plasma...

Abacavir is a novel nucleoside reverse transcriptase inhibitor for the treatment of HIV-1 infection. A simple and rapid high-performance liquid chromatographic method for the quantification of abacavir in human plasma suitable for pharmacokinetic research purposes is described. Sample pretreatment consists of protein precipitation with perchloric acid. The supernatant is injected directly into the chromatographic system after centrifugation. The drug is separated from endogenous compounds by isocratic reversed-phase high-performance liquid chromatography with ultraviolet detection at 285 nm. The method has been validated over the range of 20-2000 ng/ml using a volume of 300 microl of plasma. The assay is linear over this concentration range as indicated by the F-test for lack-of-fit. Within- and between-day precisions are less than 7.5% for all quality control samples. The lower limit of quantitation is 20 ng/ml and the recovery of abacavir is 88.1% (+/-1.3%). Frequently coadministered drugs did not interfere with the described methodology. Abacavir is stable in human plasma under various relevant storage conditions, for example when stored for 51 days at -20 degrees C. This validated assay is suited for use in pharmacokinetic studies with abacavir in human plasma and can readily be implemented in the setting of a hospital laboratory for the monitoring of abacavir concentrations.