Determination of abacavir in human plasma by high-performance liquid chromatography with ultraviolet detection and the analytical error function.

A rapid and simple high-performance liquid chromatography method has been developed for the determination of the HIV-1 reverse transcriptase inhibitor abacavir in human plasma. It included a single liquid-liquid extraction procedure with a mixture of ethyl acetate-diethyl ether prior to reversed-phase chromatography on a C18 column and C18 precolumn insert. Ultraviolet detection was set at 285 nm. The mobile phase consisted of water-acetonitrile (83:17, v/v) and the flow rate was kept at 1 mL/min. The total run time for a single analysis was 10 min. The method has been validated over the range 50-2500 ng/mL. The assay was linear over the entire concentration range (r2 = 0.9993). Intra- and inter-day precision and accuracy were less than 8.1 and -5.2%, respectively. The extraction recovery was greater than 94.3%. Abacavir was stable under the relevant storage conditions tested. After the validation, the analytical error function was established as standard deviation (SD; ng/mL) = -1.072 + 0.037C (C = theoretical concentration value). The method developed and its associated analytical error function will be suitable for pharmacokinetic studies and monitoring of HIV-1 patients. Copyright 2004 John Wiley & Sons, Ltd.