title: Enantioselective determination of dencichine in rabbit plasma by high-performance liquid chromatography-electrospray mass spectrometry.
abstract: An analytical method was developed for the determination of enantiomers of dencichine in plasma. Sample extraction from plasma was achieved by a solid-phase extraction (SPE) procedure using a C(18) cartridge, with carbocisteine as the internal standard. Plasma was deproteinized using inorganic acid and derivatizated before the SPE. Chiral separation of dencichine enantiomers was achieved by pre-column derivatization using o-phthaldialdehyde (OPA) and the chiral thiol N-isobutanoyl-L-cysteine (NIBC) to form diastereoisomeric isoindole derivatives that were separable by ODS column using a gradient solvent programme. The column eluent was monitored using mass spectrometry (MS). The conditions of MS detection were optimized, and selected ion monitoring was used to selectively detect D-dencichine and its arrangement isomer. High sensitivity and selectivity were obtained using this method. The limit of detection was determined to be 10 ng/ml for D-dencichine and 8 ng/ml for L-dencichine in plasma. The linearity was demonstrated over a wide range of concentrations, from 0.5 to 50 microg/ml for both enatiomers. The intra- and inter-day precision (C.V.), studied at four concentrations, was less than 7.0%. No interferences from endogenous amino acids and isomers of dencichine were found. The method was suitable for pharmacokinetic studies of dencichine enantiomers.
authors.affiliation: School of Pharmacy, Sichuan University, Chengdu 610041, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhu
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.forename: Hu
authors.initials: H
authors.lastname: Zheng
authors.forename: Zhangwan
authors.initials: Z
authors.lastname: Li
mesh_terms: D000599:Amino Acids, Diamino / Q000097:blood* / Q000493:pharmacokinetics; D000818:Animals; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D011817:Rabbits; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013237:Stereoisomerism
chemical_list: D000599:Amino Acids, Diamino; C100126:oxalyldiaminopropionic acid