Quantitative determination of meloxicam in dog plasma by high performance liquid chromatography-tandem mass spectrometry and its application in a pharmacokinetic study.

A rapid, selective and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed to determine meloxicam in beagle dog plasma. Sample pretreatment involved a one-step protein precipitation with methanol of 0.1 mL plasma. Analysis was performed on a Venusil ASB-C18 column with mobile phase consisting of methanol-water (containing 0.1% formic acid) (75:25, v/v). The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring mode via electrospray ionization source. Each plasma sample was chromatographed within 4.1 min. The linear calibration curves for meloxicam was obtained in the concentration range of 10.3-4.12 × 103  ng/mL (r ≥ 0.99). The intra- and inter-day precisions (relative standard deviation) were ≤ 15%, and accuracy (relative error) was within ±7.3%. The method herein described was fully validated and successfully applied to the pharmacokinetic study of meloxicam tablets in beagle dog.