The initial and final SV concentrations were determined in plasma at the start of the experiment and after 24 h incubation time with Amprenavir using a reverse-HPLC with some modification as described by Zhang et al. . The HPLC system (Waters™ 600 controller, USA) equipped with wavelength detector (Waters™ 2487 a Dual λ Absorbance detector, USA), pump (Waters™ 1252 a Binary pump, USA), and an automating sampling system (Waters™ 717 Plus Autosampler, USA) was used. The HPLC system was monitored by “Empower (Water)” software. SV was analyzed using mobile phase consisted of acetonitrile: deionized water (65:35 v/v) adjusted to pH 3.5 by phosphoric acetic acid. The mobile phase flowed over a biogeography reversed-phase C18 column (μBondapak™, 4.6 × 150 mm, 10 μm particle sizes) at a rate of 1.0 ml/min. The injection volume of each SV sample was 20 μl and detected by the UV detector at 238 nm. All the operations were carried out at room temperature.