Gliclazide
(GCZ), tolbutamide (TOL), and glipizide (GPZ) are BCS
class II antidiabetic drugs with poor aqueous solubility. Multicomponent
solid forms, salts, and cocrystals of GCZ were obtained upon liquid
assisted grinding with coformers of catechol, resorcinol, p-toluenesulfonic acid, and piperazine. The solubility of
TOL was also modified by salt formation with piperazine (PPZ). The
multicomponent solids were characterized by single crystal X-ray diffraction,
powder X-ray diffraction, Fourier transform infrared spectroscopy,
differential scanning calorimetry, and thermal gravimetric analysis
and further subjected to solubility studies. The cocrystals/salts,
in all cases, showed improvements in the solubility and dissolution
rates compared to the parent active pharmaceutical ingredients. GCZ–PPZ
and TOL–PPZ(I) showed 6.6 and 80 and fold enhancements respectively
in the solubility. The reasons for the improved solubility of the
cocrystals/salts in terms of drug–coformer interactions are
discussed.