A rapid analysis of piroxicam in beagle plasma applying evaporation-free liquid-liquid extraction by supercritical fluid chromatography-tandem mass spectrometry

Bioequivalence study is highly prized to piroxicam (PIRO), since its generic products have been widely used worldwide. The present work was undertaken to explore the pharmacokinetic behaviors and bioequivalence of two branded PIRO tablets in beagle dogs using the supercritical fluid chromatography tandem mass spectrometry (SFC-MS/MS) method. Here, a fast evaporation-free liquid-liquid extraction (EF-LLE) method using ethyl acetate was developed for extracting PIRO from beagle dog plasma. To improve the response as well as peaks elution and symmetry of analytes, several key factors were investigated including post-column compensation, stationary phase, mobile phase, column temperature, back pressure and flow rate, and finally the analytes were eluted on an ACQUITY UPC2™ BEH 2-EP column (100 × 3 mm, 1.7 μm) within only 2.5 min in optimal conditions. The performance of the established method was evaluated, good linearity was found over the concentration range of 5-5000 ng/mL (R2 ≥ 0.994) with a lower limit of quantification (LLOQ) of 5 ng/mL. Accuracy of all quality control (QC) samples were between 96.6% and 99.6% with a satisfactory intra and inter-day precision (RSD values < 6.6%). The proposed rapid, sensitive, user-friendly and high throughput method will be an alternative way for PIRO analysis in biological samples.