Optimizing Mirabegron Stability in Human Plasma: Method Development, Validation Through Integration of Esterase...

The stability of mirabegron in human plasma is addressed in this study. The susceptibility of Mirabegron to enzymatic and oxidative degradation requires the integration of esterase inhibitors and stabilizers into the analytical process. Esterase inhibitors, including sodium fluoride and dichlorvos, as well as stabilizing agents such as malic acid, ascorbic acid, acetic acid, citric acid and sodium bicarbonate were also investigated to mitigate this issue. Samples were prepared through solid-phase extraction (SPE) utilizing Strata-X cartridges. The optimization of chromatographic separation was conducted using a C18 Kromasil column with a solvent mixture consisting of ammonium formate and acetonitrile. Detection employed electrospray ionization (ESI) in positive ionization mode, focusing on MRM transitions of 397.2 → 260.1 for mirabegron and 402.2 → 260.1 for mirabegron D5. The method exhibited an accuracy range of 95.67% to 102.85% and precision of 0.52% to 2.31% for a linearity ranged from 0.100 to 102.496 ng/mL. An advantage of this method is its stability, requiring only a minimal plasma volume of 100 μL, a quick runtime of 3 min, and a high recovery rate of 92.93%, making it highly efficient and reliable for bioequivalence testing, therapeutic monitoring and pharmacokinetic studies.