Cocrystallization of gliclazide with improved physicochemical properties

Cocrystallization is one of the crystal engineering strategies used to alter the physicochemical properties of drugs that are poorly water-soluble. Gliclazide (GLZ), an antidiabetic drug, belongs to Biopharmaceutical Classification System class-II (low solubility and high permeability) and has low bioavailability, resulting in poor therapeutic effects in patients. Therefore, to impart better solubility and bioavailability of GLZ, the study was carried out by preparing GLZ cocrystals using liquid-assisted grinding method with three coformers [3,5-dinitrosalicylic acid (DNS), 2,6-pyridine dicarboxylic acid (PDA), and L-proline (LPN)], and these were characterized using Differential Scanning Colorimetry (DSC), Powder X-ray diffraction (PXRD), Fourier Transform Infra-red spectroscopy (FTIR), and Raman spectral studies. Further, Scanning electron microscopy (SEM) analysis, accelerated stability, solubility, in vitro dissolution studies, and in vivo pharmacokinetic studies were performed in male Wistar rats. DSC and PXRD analysis confirmed the formation of the GLZ cocrystals. Hydrogen bonding between pure GLZ and its coformers was demonstrated based on FTIR and Raman analysis. SEM data showed morphological images for GLZ cocrystals differed from those of pure GLZ. In comparison with pure GLZ, these GLZ cocrystals have greatly improved solubility, in vitro dissolution, and in vivo profiles. Among the three, GLZ–DNS cocrystals outperformed the pure drug in terms of solubility (6.3 times), degradation (1.5 times), and relative bioavailability (1.8 times). Hence, cocrystallization of GLZ leads to improved physicochemical properties of poorly soluble drug gliclazide.