title: Quantification of lipoic acid in plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry.
abstract: A sensitive and specific liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and quantification of lipoic acid (LA) in human plasma. LA and the internal standard, naproxen, were extracted from a 500 microl plasma sample by one-step deproteination using acetonitrile. Chromatographic separation was performed on a Zorbax SB-C(18) Column (100 mmx3.0mm i.d. with 3.5 microm particle size) with the mobile phase consisting of acetonitrile and 0.1% acetic acid (pH 4, adjusted with ammonia solution) (65:35, v/v), and the flow rate was set at 0.3 ml/min. Detection was performed on a single quadrupole mass spectrometer by selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The method was linear over the concentration range of 5-10,000 ng/ml for LA. The intra- and inter-day precisions were less than 7% and accuracy ranged from -7.87 to 9.74% at the LA concentrations tested. The present method provides a relatively simple and sensitive assay with short turn-around time. The method has been successfully applied to a clinical pharmacokinetic study of LA in 10 healthy subjects.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Fudan University, 138 Yi Xue Yuan Road, BOX 130, Fenglin Campus, Shanghai 200032, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Wenming
authors.initials: W
authors.lastname: Jiang
authors.forename: Jia
authors.initials: J
authors.lastname: Cai
authors.forename: Weixing
authors.initials: W
authors.lastname: Tao
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Gao
authors.forename: Xinguo
authors.initials: X
authors.lastname: Jiang
mesh_terms: D000284:Administration, Oral; D000975:Antioxidants / Q000008:administration & dosage / Q000493:pharmacokinetics; D019540:Area Under Curve; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006207:Half-Life; D006801:Humans; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D008063:Thioctic Acid / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D000975:Antioxidants; D008063:Thioctic Acid