Investigation on Polymorphs of Apixaban, an Anticoagulant Drug: Study of Phase Transformations and Designing Efficient Process for their Preparation

The present work describes the investigation on the polymorphs of Apixaban (1), an anticoagulant drug obtained by following basic synthetic process known in the prior art. Polymorphs present inherently in the basic process are identified, synthesized and characterized. Robust and efficient process for the preparation of apixaban (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. Process optimization details conducted towards the synthesis of identified polymorphs of apixaban with high chemical and polymorphic purity are presented.