A rapid, sensitive and high throughput UHPLC-MS/MS method was established and validated to assay the concentration of 2-(2-hydroxypropanamido) benzoic acid (HPABA), a promising anti-inflammatory drug, in rat plasma. Plasma samples were processed by liquid-liquid extraction with ethyl acetate and separated on a Shim-pack XR-ODS C18 column (75 mm×3.0 mm, 2.2 μm) at an isocratic flow rate of 0.4 mL/min using acetonitrile-0.1% formic acid in water (50:50, v/v) as mobile phase, and total run time was 2 min. MS/MS detection was accomplished in multiple reaction monitoring (MRM) mode with positive electrospray ionization. The calibration curve was linear over the concentration range of 0.01-50 μg/mL with lower limit of quantification of 0.01 μg/mL. The intra- and inter-day precisions were below 8.5% in terms of relative standard deviation (RSD), and the accuracy was within ±4.0% in terms of relative error (RE). Extraction recovery, matrix effect and stability were satisfactory in rat plasma. The developed method was successfully applied to a pharmacokinetic study of HPABA following intragastric administration of 25, 50, 100mg/kg and an intravenous injection at a dose of 12.5 mg/kg to Sprague-Dawley rats. Results indicated that HPABA had linear pharmacokinetic properties within the tested intragastric dosage range and the absolute bioavailability was above 59.1%.
Keywords: 2-(2-Hydroxypropanamido) benzoic acid; Liquid–liquid extraction; Pharmacokinetics; Rat; UHPLC–MS/MS.
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