Identification of Selexipag amorphous Polymorphs and Development of an Efficient Synthetic Process for Their Preparation.

Abstract

The present work describes a novel amorphous polymorphic form of Selexipag (1), a drug used for the treatment of pulmonary arterial hypertension, along with its preparation process. The compound was obtained through an improved synthetic process based on prior art. The polymorphic forms inherently present in the base process were identified, isolated, synthesized, and thoroughly characterized. A Robust and efficient process for the preparation of Selexipag (1) and their different polymorphs has been described based on the understanding of solvent mediated phase transformations, solid-solid phase transformation and suitable medium in which phases are effectively formed. Furthermore, process optimization studies for the synthesis of the identified polymorphs of Selexipag (1) are presented, demonstrating the achievement of high chemical and polymorphic purity.