Simultaneous Determination of Parecoxib and Its Metabolite Valdecoxib Concentrations in Beagle Plasma by UPLC-MS/MS and Application for Pharmacokinetics Study

Shuang-long Li, Yong-liang Zhu, Chun-yang Zhu, Shao-bin Li, Zi-heng Li, Xiang-jun Qiu Medical College of Henan University of Science and Technology, Luoyang 471023, People’s Republic of ChinaCorrespondence: Xiang-jun QiuMedical College of Henan University of Science and Technology 471023, People’s Republic of ChinaTel +86 13698882699 Fax + 86 379-64830346 Email lyxiangjun@126.comAbstract: A method for the simultaneous determination of parecoxib and its metabolite valdecoxib in beagle plasma by UPLC-MS/MS was developed and validated. After the plasma was extracted by acetonitrile precipitation, the analytes were separated on an Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) using acetonitrile-formic acid as the mobile phase in gradient mode. The analytes were monitored by multiple reaction monitoring (MRM) in electrospray negative ion mode. The mass transfer pairs were m/z 368.97→ 119.01 for parecoxib, m/z 312.89→ 118.02 for valdecoxib, and m/z 379.98→ 316.02 for celecoxib (internal standard, IS). The correlation coefficients of parecoxib and valdecoxib ranged from 5 to 4000 ng/mL were greater than 0.9998. The recovery of parecoxib and valdecoxib was greater than 82.54%. The inter- and intra-day precision RSD values were 1.36∼ 3.65% and 2.28∼ 5.91%, respectively. The accuracy of RE values were − 1.38%∼ 1.96%. Finally, the matrix effect (ME) and stability were also within acceptable criteria. This method had been successfully applied to the pharmacokinetics of parecoxib and valdecoxib in beagle plasma after injection of parecoxib (1.33 mg/kg, intramuscular injection).Keywords: parecoxib, valdecoxib, UPLC-MS/MS, pharmacokinetics