An LC-MS-MS Method for Quantification of CMDCK: A Novel Anti-HIV Agent in Rat Plasma and Its Application to a Pharmacokinetic Study

A simple and sensitive LC-MS-MS method was developed and validated to quantify CMDCK, a novel non-nucleoside reverse transcriptase inhibitor in rat plasma. A simple protein precipitation with acetonitrile was used to pretreat plasma samples. Chromatographic separation was carried out on a Hypersil GOLD-C-18 (50 mm x 2.1 mm, 5 mu m) column with the mobile phase consisting of acetonitrile and 0.1% formic acid solution (60:40 v/v) at a flow rate of 0.2 mL min(-1). A triple-quadrupole tandem mass spectrometer with ESI source was operated in the positive ion mode. Quantitative analysis was conducted in the selected reaction monitoring mode with precursor/product ion transitions of m/z 698/500 and 693/495, respectively for CMDCK and IS. The calibration curves were linear over the concentration range of 5-2,000 ng mL(-1) with the lower limit of quantification of 5 ng mL(-1). The intra- and inter-day precisions and accuracies were satisfactory, with the coefficient of variation and the relative error being less than 13.2 and 3.38%, respectively. The recovery of CMDCK in plasma ranged from 84.6 +/- A 6.5 to 100.8 +/- A 9.3%. This LC-MS-MS method was successfully used as a new approach for the preclinical pharmacokinetics study of CMDCK in rat.