Simultaneous determination of the HIV protease inhibitors indinavir, amprenavir, saquinavir, ritonavir and nelfinavir in human plasma by high-performance liquid chromatography

Abstract

A reversed-phase high-performance liquid chromatographic method for the simultaneous quantitative determination of five HIV protease inhibitors (i.e. indinavir, amprenavir, saquinavir, ritonavir and nelfinavir) in human plasma is described. An aliquot of 500 μl plasma was extracted with 0.5 ml of 0.1 M NH 4OH and 5 ml of methyl tert.-butyl ether. After evaporating, the residue was dissolved in eluent mixture of acetonitrile and 50 m M KH 2PO 4 adjusted to pH 5.6 with 50 m M Na 2HPO 4 (43:57, v/v). Subsequently, the eluent was washed with hexane. Chromatography was performed using a C 18 reversed-phase column. Ultraviolet detection at 215 nm was used. Linearity of the method was obtained in the concentration range of 0.05–20 μg ml −1 for all five protease inhibitors. Our method is now in use to analyse plasma samples from patients treated with co-administration of HIV protease inhibitors.