Novel Drug-Drug Cocrystalline Forms of Carbamazepine with Sulfacetamide: Preparation, Characterization, and In Vitro/In Vivo Performance Evaluation.

Objectives

Drug-drug cocrystallization represents a promising approach for the development of novel combination drugs with improved physicochemical and biopharmaceutical properties. The aim of the present research is to prepare novel drug-drug cocrystalline forms of antiepileptic drug carbamazepine (CBZ) with sulfacetamide (SCTM).

Methods

The novel CBZ cocrystal methanol solvate and cocrystal hydrate were prepared via solvent evaporation technique and characterized by single crystal X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis.

Results

Single-crystal X-ray diffraction and thermal analysis revealed that the multicomponent solids are isostructural, wherein the solvent molecule does not play a structure-forming role. To optimize the synthesis of [CBZ+SCTM+H2O] (1:1:0.7), the binary and ternary phase diagrams were constructed in acetonitrile at 25 °C. A thorough investigation of the cocrystal hydrate behavior in aqueous solution showed that the pH of the dissolution medium exerted a significant effect on the stability and solubility of [CBZ+SCTM+H2O] (1:1:0.7). According to the dissolution and diffusion experiments in a buffer solution pH 6.5, the cocrystal hydrate characterized an enhanced dissolution rate and flux of CBZ. Pharmacokinetic studies in rabbits showed that the novel cocrystal hydrate exhibited a comparable bioavailability to the parent CBZ.

Conclusions

Overall, this work reports the preparation of a novel CBZ drug-drug cocrystal hydrate, which can be considered as an alternative CBZ solid form for oral usage, possessing additive pharmacological effect.