Simultaneous Determination of Six HIV Protease Inhibitors, One Metabolite, and Two Non-nucleoside Reverse Transcriptase Inhibitors in Human Plasma by Isocratic Reversed-Phase Liquid Chromatography After Solid-Phase Extraction

Abstract

Summary A selective and sensitive high-performance liquid chromatographic (HPLC) method has been developed and validated for the determination of six human immunodeficiency virus (HIV)-protease inhibitors (amprenavir, indinavir, lopinavir, nelfinavir, ritonavir, and saquinavir) and two non-nucleoside reverse transcriptase inhibitors (efavirenz and nevirapine) in a single run. This involve a simple liquid-solid extraction on OASIS^® HLB column in the presence of an internal standard (prazepam). Separation is achieved on a Xterra^®, C₁₈ (150 × 3.9 mm I. D.) column with a mobile phase consisting of acetonitrile and 3-(cyclohexylamino)-1-propanesulfonic acid (CAPS) buffer pH 10.5, (37 : 63, v/v) delivered isocratically. A sequential ultraviolet detection (5 minutes sequence set at 320 nm for nevirapine acquisition and 55 minutes at 210 nm for other durgs and internal standard) is performed. The method is linear over the specific ranges investigated. Precision and accuracy at four concentrations are respectively less than 13.6% and 9.1% for intraday assays and less than 4.2% and 5.9% for interday assays. This method is suitable for therapeutic drug monitoring purpose and routinely used in our laboratory.