title: [Determination of lornoxicam in human plasma by LC/MS/MS].
abstract: OBJECTIVE
  To develop a sensitive and specific LC/MS/MS method for determination of lornoxicam in human plasma and investigate pharmacokinetics of single dose of lornoxicam in healthy Chinese volunteers.
  
  
  METHODS
  Lornoxicam and the internal standard piroxicam were extracted from plasma using liquid-liquid extraction, then separated on a Zorbax XDB-C8 column. The mobile phase consisted of methanol-water-formic acid (80:20:0.5) at a flow-rate of 0.7 mL.min-1. A Finnigan TSQ tandem mass spectrometer equipped with atmospheric pressure chemical ionization source was used as detector and operated in the positive ion mode. Selected reaction monitoring (SRM) using the precursor-->product ion combinations of m/z 372-->121 and m/z 332-->121 was used to quantify lornoxicam and internal standard, respectively.
  
  
  RESULTS
  The linear calibration curves were obtained in the concentration range of 2.0-1,600 micrograms.L-1. The limit of quantitation was 2.0 micrograms.L-1. The method was successfully used in the pharmacokinetic study for lornoxicam. The main parameters obtained after an oral dose of 8 mg lornoxicam to 18 Chinese male volunteers were as follows: the value of T1/2 was (4.7 +/- 1.1) h, AUC0-infinity was found to be (5.5 +/- 2.4) mg.h.L-1. However, T1/2 of 105 h and AUC0-infinity of 189.5 mg.h.L-1 were obtained for another volunteer.
  
  
  CONCLUSIONS
  The method is proved to be suitable for clinical investigation of lornoxicam pharmacokinetics, which offers advantages of specificity, speed, and higher sensitivity over the previously reported methods.
authors.affiliation: Laboratory of Drug Metabolism and Pharmacokinetics, Shenyang Pharmaceutical University, Shenyang 110016, China.
authors.forename: Ya-lin
authors.initials: YL
authors.lastname: Zeng
authors.forename: Xiao-yan
authors.initials: XY
authors.lastname: Chen
authors.forename: Yi-fan
authors.initials: YF
authors.lastname: Zhang
authors.forename: Da-fang
authors.initials: DF
authors.lastname: Zhong
mesh_terms: D000284:Administration, Oral; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D019540:Area Under Curve; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D010894:Piroxicam / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood* / Q000493:pharmacokinetics; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D010894:Piroxicam; C059451:lornoxicam