Towards the development of a polymorphic control approach in sulfathiazole crystalization

Controlling the formation of a specific polymorphic form of active pharmaceutical ingredients, particularly those that exhibit multiple polymorphic forms, during crystallization is critical for pharmaceutical manufacturers. This paper describes the construction of a phase diagram using Lasentec Focused Beam Reflectance Measurement (FBRM), which is an important step in the development of an approach for polymorphic control of sulfathiazole, an antimicrobial agent that is known to crystallize as a mixture of polymorphs. A preliminary work on mapping of different regions in the phase diagram, where various polymorphic forms were found, is also reported here. This study is part of a larger study on polymorphic control of pharmaceuticals through supersaturation control using Process Analytical Technology.