Review Article on High Throughput Screening A Demanding Technique in Polymorph Selection

Abstract

Polymorph screening is an effort in the direction of finding out whether a given compound exists in polymorphic forms or not, if yes then how many polymorphic forms of the given compounds exist? In simple words, Polymorph screening is the process of identification and characterization of nearly all possible but relevant polymorphs of any compound. (1) The practice of screening is different from that of polymorph or crystal selection. In the screening polymorphic forms and their identities are found out, whereas in the polymorph selection, the properties of various forms found in the screening are investigated to determine which one has the best properties for a particular use. It is polymorph selection that is being practiced in industry rather than simple screening since polymorph screening of some APIs, having complexity in polymorph profile, is somewhat difficult and challenging. (2) Polymorph screening helps in the selection of the solid form to be prepared for any active pharmaceutical ingredient (API). During polymorph screening several solid forms of the drug candidate are generated and analyzed at small level of preparation and then characterized by commonly available techniques, for example, solvent evaporation crystallization, antisolvent addition, cooling of saturated solutions of API at different rates, making slurries for extended periods. (2) It is self understood that other solid forms should not be neglected as they too may possess properties which make them suitable for further development.