Mifepristone polymorph with enhanced solubility, dissolution and oral bioavailability

Mifepristone is one of potent anti-progesterone agents, which binds to progesterone receptors and glucocorticoid receptors. Until now, there are a lot of research focusing on enhancing the solubility and oral bioavailability of Mifepristone. However, poor solubility and oral bioavailability has some undesirable consequences. In this work, Mifepristone in form D was discovered for the first time and characterized by PXRD, TGA, DSC, FT-IR, SEM and S-S NMR. Form D was a metastable crystal type which manifested favorable stability under ambient conditions. Form D had better dissolution characteristic compared with commercial Mifepristone in 0.5% SDS solution. In addition, Mifepristone in form D exhibited a 1.43-fold higher peak plasma concentration (C-max) and 1.46-fold higher area under the curve (AUC) in rats. The work in this paper is a complement to the present understanding of drug polymorphism on the in vitro and in vivo behavior, and establishes the ground work for future development of Mifepristone in form D as a promising drug for the market.