Crystallization of the Racemic Conglomerate and Racemic Compound of Efonidipine

Abstract

Abstract-Efonidipine is a dual blocker of T-type and L-type calcium channels with 1, 4-dihydropyridine structure attached to a phosphonate skeleton. As a chiral compound, it has a special property that can exist as a racemic conglomerate or a racemic compound based on the different crystallization conditions. One racemic conglomerate and one racemic compound were disclosed and characterized in this research. Efonidipine conglomerate could obtain from its racemic solution when ethanol, methanol, tetrahydrofuran, ethyl acetate and acetonitrile were chosen as the crystallized solvent. While, racemic compound which existed as an acetone solvate could be prepared by crystallization from acetone only and the crystallization process must be keep stood without agitating. In order to confirm this conclusion, three single crystals of R-efonidipine, S-efonidipine and R/S-efonidipine acetone solvate have been prepared and determined.