Extraction of mycophenolic acid from biological samples to its determination by terbium-sensitized luminescence method

Abstract

Introduction: Mycophenolic Acid (MPA) is an immunosuppressant drug used to prevent organ rejection and for the treatment of autoimmune diseases. Because of the narrow therapeutic index, measuring the plasma’s concentration of MPA and therapeutic drug monitoring (TDM) is an important issue. Salting-out liquid liquid microextraction was used for clean-up of plasma sample and spectrofluorimetry was used for measuring of the low concentrations of analytes in biological samples. Terbium-sensitized luminescence methods are widely used for the determination of drugs in pharmaceutical preparations and biological samples in recent years. Aim: In this study, an analysis method was developed for the determination of MPA in plasma samples using salting-out liquid liquid microextraction of MPA from plasma samples based on the formation of a fluorescent complex with terbium ions. Methods: Main affecting factors for the extraction of MPA; i.e. pH, volume of acetonitrile and salt concentration were examined and optimized, then, the fluorescence intensity of MPA was measured at 545 nm using an excitation wavelength set at 347 nm. MPA concentration was obtained using a calibration curve prepared with standard solutions. Results: Under the optimum conditions, developed analytic method, provided a linear calibration curve in the range between 0.5 to 5 mg/L with a correlation coefficient (R2) of 0.9981 and limit of detection (LOD) and limit of quantification (LOQ) of 0.1 mg/L and 0.33 mg/L, respectively. Conclusion: The extraction method can be succesfully used for the extraction and clean-up of MPA from plasma samples. The spectrofluorimetr method with a low sensitivity can be used to measure the concentration of MPA in the real plasma samples.