The effective direct resolution procedure for the chiral drug bevantolol hydrochloride

The solubility of the chiral drug bevantolol hydrochloride 1 in water and the azeotropic mixture ethanol–water has been investigated. It was found that rac-1 meets the requirements of Meyerhoffer’s rule, so it was possible to reduce the ternary diagram, describing the solubility of 1, to a pseudo binary form, which facilitates the analysis of crystallization processes caused by temperature changes. On this basis, the effective and robust resolution procedure of racemic bevantolol hydrochloride by a preferential crystallization approach has been realized successfully.