Preparation and Characterization of Gliclazide - Vitamin C Eutectic Mixture for Improved Dissolution Rate

This study investigates the potential of binary mixtures of gliclazide (GCL) and Vitamin C i.e. ascorbic acid (ASC) in various molar ratios to address the minimal aqueous solubility and dissolution characteristics of GCL. The results reveal that GCL and ASC form a eutectic mixture, at a 1:1 molar ratio exhibiting the eutectic melting temperature (T_Eut) at 148.60°C, as determined through phase diagram construction employing differential scanning calorimetry (DSC) and thermo-microscopy. The presence of eutectic formation was confirmed by powder X-ray diffraction (PXRD) and furrier transform infrared (FTIR) spectroscopy indicating the absence of molecular interaction within the two components in the solid state. GCL-ASC eutectic mixture significantly enhanced the solubility, wettability, and dissolution rate of GCL, with ASC serving as a water-soluble carrier. Furthermore, in the presence of excipients, the GCL-ASC mixture exhibited a superior dissolution rate compared to pure GCL. These findings underscore the potential of eutectic mixtures as a promising strategy for improving the solubility and dissolution performance of poorly water-soluble drugs like gliclazide, highlighting the importance of this work in advancing pharmaceutical formulation and bioavailability enhancement.