POLYMORPHISM OF SULINDAC - ISOLATION AND CHARACTERIZATION OF A NEW POLYMORPH AND 3 NEW SOLVATES

The polymorphism of sulindac was investigated. Two polymorphs (I and I I) and a new crystalline form (form III) of sulindac were prepared by recrystallization in different solvents. In addition, three new pseudo polymorphs (solvates) from acetone, chloroform, and benzene were obtai ned, with each containing 1 mol of solvent to 2 mol of sulindac. Diffe rent sulindac polymorphs and pseudopolymorphs were characterized by X- ray diffractometry, infrared spectroscopy, differential scanning calor imetry (DSC), thermogravimetric analysis (TGA), and hot-stage microsco py. The transition behavior of the crystalline forms of sulindac, thei r melting points, and their enthalpies were investigated by DSC. The m elting of form II was observed at 184 degrees C, and form I subsequent ly recrystallized from this melt. Similarly, form III melts at 145 deg rees C and then recrystallizes to form I. We also investigated the inf luence of the crystallization solvent on sulindac crystal shape.