Polymorphic Characterization and Bioavailability of Nomegestrol Acetate

Polymorph screening is currently one of the most important strategies of innovators and generic companies from both pharmaceutical and intellectual property rights perspectives. Different polymorphs may have varying physicochemical properties which influence the bioavailability. The purpose of this study was to investigate the crystal structures and physicochemical properties of Nomegestrol acetate(NOMAC) polymorphs. Forms I and II(dioxane solvate) were isolated and prepared by systemic crystallization screening in this study, and the forms are reported for the first time. A structural analysis and comparison of all the forms are presented. This study was also the first time to apply a rapid and feasible ultra-highperformance-liquid chromatography(UHPLC)-electrospray ionization(ESI)-tandem mass spectrometry(MS) method to determine plasma levels of NOMAC within 3.0 mins. And this study demonstrated that the optimal crystal Form I displayed higher bioavailability than API indicating that Form I could be an alternative solid form that needs further research.