title: A sensitive and selective HPLC/ESI-MS/MS assay for the simultaneous quantification of 16-dehydropregnenolone and its major metabolites in rabbit plasma.
abstract: A sensitive, selective and rapid liquid chromatographic/electrospray ionization tandem mass spectrometric assay was developed and validated for the simultaneous quantification of 16-dehydropregnenolone (DHP) and its five metabolites 4,16-pregnadien-3, 20-dione (M(1)), 5-pregnene-3beta-ol-20-one (M(2)), 5-pregnene-3beta, 20-diol (M(3)), 5-pregnene-3beta-ol-16, 17-epoxi-20-one (M(4)) and 5,16-pregnadien-3beta, 11-diol-20-one (M(5)) in rabbit plasma using dexamethasone as internal standard (IS). The analytes were chromatographed on Spheri-5 RP-18 column (5 microm, 100 mm x 4.6 mm i.d.) coupled with guard column using acetonitrile:ammonium acetate buffer (90:10, v/v) as mobile phase at a flow rate of 0.65 ml/min. The quantitation of the analytes was carried out using API 4000 LC-MS-MS system in the multiple reaction monitoring (MRM) mode. The method was validated in terms of linearity, specificity, sensitivity, recovery, accuracy, precision (intra- and inter-assay variation), freeze-thaw, long-term, auto injector and dry residue stability. Linearity in plasma was observed over a concentration range of 1.56-400 ng/ml with a limit of detection (LOD) of 0.78 ng/ml for all analytes except M(3) and M(5) where linearity was over the 3.13-400 ng/ml with LOD of 1.56 ng/ml. The absolute recoveries from plasma were consistent and reproducible over the linearity range for all analytes. The intra- and inter-day accuracy and precision method were within the acceptable limits and the analytes were stable after three freeze-thaw cycles and their dry residues were stable at -60 degrees C for 15 days. The method was successfully applied to determine concentrations of DHP and its putative metabolites in plasma during a pilot pharmacokinetic study in rabbits.
authors.affiliation: Pharmacokinetics and Metabolism Division, Central Drug Research Institute, Chattar Manzil Palace, Lucknow, India.
authors.forename: Satyendra
authors.initials: S
authors.lastname: Suryawanshi
authors.forename: S K
authors.initials: SK
authors.lastname: Singh
authors.forename: R C
authors.initials: RC
authors.lastname: Gupta
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D011284:Pregnenolone / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D011817:Rabbits; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: C003592:16-dehydropregnenolone; D011284:Pregnenolone