Quantitative determination of new anti-inflammatory drug indomenthyl and its metabolite in rabbit plasma by HPLC-MS/MS

Background: Indomenthyl is an innovative anti-inflammatory drug with a high analgesic activity. Indomenthyl releases indomethacin under the influence of neutrophil esterases in the inflammation focus. Methodology/results: This research is aimed at developing a highly sensitive method for the quantitative determination of indomenthyl and its active metabolite indomethacin in rabbit plasma by HPLC-MS/MS. Protein precipitation and extraction with acetonitrile were used for analyte isolation from plasma according to the QuEChERS principle. The target quantitative ion pairs m/z were respectively 496.4 -> 358.0 for indomenthyl, 358.0 -> 139.5 for indomethacin, and 340.1 -> 202.1 for the IS. Conclusion: The calibration curve was linear over the range 0.1-1000 ng mL(-1). The technique was applied to the pharmacokinetic study at a dose of 25 mg kg(-1) to rabbits.