Heterogeneous crystallization of Chlorzoxazone for modulating the physicochemical properties of crystals

The polymer on modulating the crystal's habit is an evolving research in pharmaceutical crystallization. This study demonstrates the crystal habit modification of chlorzoxazone (CHZ) by heterogeneous crystallization (HC) in the binary solvent acetonitrile-ethanol (A-E (1:1)) in the presence of polyvinylpyrrolidine (PVP) at concentrations of 0.50, 0.75, and 1.00 wt%. The A-E (1:1) and PVP in HC experiments influenced to change the shape of crystals from needle to plate shape and reduced the crystal size producing a lower aspect ratio (in the range of 1.5–2.3). In the presence of PVP, the CHZ size distribution is 65–78 μm which tends to enhance the powder flow-ability of CHZ crystals and as the PVP concentration increases, the nucleation rate decreases. The solubility of size-reduced CHZ crystals at different pH is found to be improved by 1.2–1.4 times. Hence, HC is deemed effective in modifying the physicochemical attributes of CHZ.