EXPLORING STRUCTURAL ASPECTS OF NATEGLINIDE POLYMORPHS USING POWDER X-RAY DIFFRACTION

Objective: The present manuscript highlights the structural aspects of some polymorphic forms of nateglinide using powder x-ray diffraction (PXRD) pattern.Methods: All the polymorphic forms were isolated as microcrystalline powder, therefore, powder diffraction patterns was used as a tool to determine the crystal structure. For this, Reflux Plus module of BIOVIA Material Studio software was used. Polymorph prediction (PP) and crystal morphology analysis were performed to estimate the global minimum in lattice energy landscape and morphologically important (M. I.) facets, respectively. Besides this, to investigate the behavior of polymorphs in solution phase, in vitro studies (enthalpy of solution, solubility, intrinsic dissolution rate) were also performed.Results: A new form MS was prepared and characterized. The Form H, B, MS and S were found to exist in space group P-1, C2, P-4 and P-42C, respectively. These crystal structures were found to lie on local minima in crystal energy landscape. The stability ranking of nateglinide polymorphs follows the order: Form MS<Form B<Form H<Form S.Conclusion: This research work demonstrates that PXRD is a valuable alternative for determining the structure of microcrystalline powders.