title: Stereoselective analysis of tiopronin enantiomers in rat plasma using high-performance liquid chromatography-electrospray ionization mass spectrometry after chiral derivatization.
abstract: A specific and relatively sensitive high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS) was developed for the quantitative analysis of tiopronin enantiomers in rat plasma. The method is based on the derivatization of (+)-tiopronin and (-)-tiopronin with 2,3,4,6-tetra-O-acetyl-beta-glucopyranosyl isothiocyanate (GITC) in acetonitrile. The separation of resulting diastereomic derivatives was performed on C18 column (150 mm x 2.0 mm ID, packed with 5.0 mum C(18) silica RP particle), using a mobile phase of methanol/water (containing 5.3 mM formic acid) with gradient elution. LC-MS was performed in the selected ion monitoring and positive ion mode using target ions at m/z: 575 for the diastereomic derivatives of tiopronin and m/z: 603 for the derivative of N-isobutyryl-D-cysteine (internal standard). The method was validated in terms of specificity, linearity, sensitivity, precision, accuracy, matrix effect, and stability. The calibration curves were linear over the concentration range of 0.025-5 microg/ml for both enantiomers of tiopronin. For both enantiomers of tiopronin, the interbatch and intrabatch variability values were less than 15%, and the accuracy was within +/-17% in terms of relative error. The method was successfully applied to a pharmacokinetic study of rac-tiopronin in rat.
authors.affiliation: Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 21009, People's Republic of China.
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.forename: Chen
authors.initials: C
authors.lastname: Ma
authors.forename: Jia
authors.initials: J
authors.lastname: Zhou
authors.forename: Xiao Quan
authors.initials: XQ
authors.lastname: Liu
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D012106:Research; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism; D008625:Tiopronin / Q000097:blood* / Q000737:chemistry*
chemical_list: D008625:Tiopronin