Correlation of Solubility Thermodynamics of Glibenclamide with Recrystallization and In Vitro Release Profile

Abstract

The solubility of glibenclamide was evaluated in DMSO, NMP, 1,4-dioxane, PEG 400, Transcutol(R) HP, water, and aqueous mixtures (T = 293.15 similar to 323.15 K). It was then recrystallized to solvate and compressed into tablets, of which 30-day stability and dissolution was studied. It had a higher solubility in 1,4-dioxane, DMSO, NMP (X-exp = 2.30 x 10(3), 3.08 x 10(4), 2.90 x 10(4)) at 323.15 K, its mixture (X-exp = 1.93 x 10(3), 1.89 x 10(4), 1.58 x 10(4)) at 298.15 K, and 1,4-dioxane (w) + water (1-w) mixture ratio of w = 0.8 (X-exp = 3.74 x 10(3)) at 323.15 K. Modified Apelblat (RMSD <= 0.519) and CNIBS/R-K model (RMSD <= 0.358) suggested good comparability with the experimental solubility. The minimum value of Delta G degrees vs Delta H degrees at 0.70 < x(2) < 0.80 suggested higher solubility at that molar concentration. Based on the solubility, it was recrystallized into the solvate, which was granulated and compressed into tablets. Among the studied solvates, the tablets of glibenclamide dioxane solvate had a higher initial (95.51%) and 30-day (93.74%) dissolution compared to glibenclamide reference (28.93%). There was no stability issue even after granulation, drying, or at pH 7.4. Thus, glibenclamide dioxane solvate could be an alternative form to improve the molecule's properties.