Understanding Pharmaceutical Polymorphic Transformations II: Crystallization Variables and Influence on Dosage Forms

Abstract

Excipients or formulation variables have often been exploited to improve stability, modify release, or improve physicochemical properties of dosage forms. In pharmaceutical field, it is generally expected that excipients work at macromolecular level where they might influence the crystal structure of a solid. These polymers/colloidal particles may modify the rate and direction of crystal growth. It has also been observed, that different polymorphic crystals exhibit different colors on exposure to same colorant, predominantly due to difference in surface pH of different crystal lattices. Apart from physicochemical affect, crystal habit also influences pharmacokinetic parameters of the dosage form. Crystals with smaller size or lower lattice energy have shown to exhibit higher bioavailability with faster rate of release.

Application of Polymers as a Tool in Crystallization—A Review

“…Thakore et al in their review paper presented recent findings in the primary heterogeneous crystallization with specific emphasis on its pharmaceutical applications [ 88 ]. Sood et al discussed how excipients or formulation variables such as type of solvent, presence of hydrophilic adjuvants, surfactants, dyes and colorants improve stability, modify release and improve physicochemical properties of dosage forms [ 89 ].…”