title: Determination of betamethasone and betamethasone 17-monopropionate in human plasma by liquid chromatography-positive/negative electrospray ionization tandem mass spectrometry.
abstract: This study presents a high-performance liquid chromatography-positive/negative electrospray ionization tandem mass spectrometric (LC-ESI(+/-)-MS-MS) method for the determination of betamethasone (BOH) and betamethasone 17-monopropionate (B17P) in human plasma using beclomethasone dipropionate as the internal standard (I.S.). Both compounds were extracted from human plasma with ether-cyclohexane (4:1, v/v) and were separated by HPLC on a Hanbon Lichrospher C(18) column with a mobile phase of methanol-water (85:15, v/v) at a flow rate of 0.7ml/min. Calibration curves were linear over the range of 0.10-50ng/ml for BOH and 0.050-50ng/ml for B17P. The inter-run relative standard deviations were less than 14.4% for BOH and 12.3% for B17P. The intra-run relative standard deviations were less than 9.3% for BOH and 7.9% for B17P. The mean plasma extraction recovery for BOH and B17P were in the ranges of 82.7-85.9% and 83.6-85.3%, respectively. The method was successfully applied to study the pharmacokinetics of a new formulation of betamethasone phosphate/betamethasone dipropionate injection in healthy Chinese volunteers.
authors.affiliation: Department of Clinical Pharmacology, Nanjing First Affiliated Hospital of Nanjing Medical University, Nanjing 210006, PR China. zoujianjun100@126.com
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Zou
authors.forename: Li
authors.initials: L
authors.lastname: Dai
authors.forename: Li
authors.initials: L
authors.lastname: Ding
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Xiao
authors.forename: Zhu-Yu
authors.initials: ZY
authors.lastname: Bin
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Fan
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Guang-Ji
authors.initials: GJ
authors.lastname: Wang