A Procedure for Determining Dexketoprofen Trometamol in Human Plasma and Its Validation

A procedure for the determination of dexketoprofen trometamol in human plasma by liquid chromatography–mass spectrometry (HPLC–MS/MS) using ibuprofen as an internal standard was proposed and validated. The matrix effect on the analyte response value was estimated; its short-term and long-term stability in a biological matrix and an aqueous acetonitrile solution was investigated. In addition, the stability of the analyte after freezing and thawing of samples was studied. It was shown that the dilution of samples by one half does not affect the accuracy and precision of the analysis. The limit of detection and the lower limit of quantification were 0.01 µg/mL; the linearity range was 0.01–8.50 µg/mL (R2 = 0.9974); the total analysis time was 3.5 min. Intra- and interday accuracy values were in the ranges 96.66–100.00% and 94.97–97.92%, respectively. Sample preparation, including liquid–liquid extraction with ethyl acetate in an acidic medium, is simple and fast. The developed procedure was successfully tested on real plasma samples from healthy volunteers in the framework of a comparative study of the pharmacokinetics and bioequivalence of a generic drug.