title: Simultaneous determination of phentermine and topiramate in human plasma by liquid chromatography-tandem mass spectrometry with positive/negative ion-switching electrospray ionization and its application in pharmacokinetic study.
abstract: A new method for simultaneous determination of phentermine and topiramate by liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) operated in positive and negative ionization switching modes was developed and validated. Protein precipitation with acetonitrile was selected for sample preparation. Analyses were performed on a liquid chromatography system employing a Kromasil 60-5CN column (2.1 mm × 100 mm, 5 μm) and an isocratic elution with mixed solution of acetonitrile-20mM ammonium formate containing 0.3% formic acid (40:60, v/v), at a flow rate of 0.35 mL/min. Doxazosin mesylate and pioglitazone were used as the internal standard (IS) respectively for quantification. The determination was carried out on an API 4000 triple-quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode using the following transitions monitored simultaneously: positive m/z 150.0/91.0 for phentermine, m/z 452.1/344.3 for doxazosin, and negative m/z 338.3/77.9 for topiramate, m/z 355.0/41.9 for pioglitazone. The method was validated to be linear over the concentration range of 1-800 ng mL(-1) for phentermine, 1-1000 ng mL(-1) for topiramate. Within- and between-day accuracy and precision of the validated method at three different concentration levels were within the acceptable limits of <15% at all concentrations. Blood samples were collected into heparinized tubes before and after administration. The simple and robust LC/MS/MS method was successfully applied for the simultaneous determination of phentermine and topiramate in a pharmacokinetic study in healthy male Chinese volunteers.
authors: Institute of Clinical Pharmacy, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, PR China.
authors: Yang
authors: Y
authors: Ni
authors: Institute of Clinical Pharmacy, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, PR China.
authors: Ying
authors: Y
authors: Zhou
authors: Institute of Clinical Pharmacy, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, PR China.
authors: Mingzhen
authors: M
authors: Xu
authors: Institute of Clinical Pharmacy, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, PR China.
authors: Xiaomeng
authors: X
authors: He
authors: Institute of Clinical Pharmacy, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, PR China.
authors: Huqun
authors: H
authors: Li
authors: Institute of Clinical Pharmacy, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, PR China.
authors: Satter
authors: S
authors: Haseeb
authors: Department of Infectious Disease, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, PR China. Electronic address: shining_119@163.com.
authors: Hui
authors: H
authors: Chen
authors: Institute of Clinical Pharmacy, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, PR China. Electronic address: wenzhang_sci@163.com.
authors: Weiyong
authors: W
authors: Li
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D005632:Fructose / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics; D006801:Humans; D007477:Ions / Q000737:chemistry*; D010645:Phentermine / Q000737:chemistry* / Q000493:pharmacokinetics*; D000077205:Pioglitazone; D010949:Plasma / Q000737:chemistry*; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods; D045162:Thiazolidinediones / Q000737:chemistry / Q000493:pharmacokinetics; D000077236:Topiramate
chemical_list: D007477:Ions; D045162:Thiazolidinediones; D000077236:Topiramate; D005632:Fructose; D010645:Phentermine; D000077205:Pioglitazone
keywords: LC–MS/MS; Pharmacokinetics; Phentermine; Switching modes; Topiramate