Cilostazol Solubilization and Stabilization Using a Polymer-Free Solid Dispersion System

Purpose The development of pH-independent drugs is difficult because it involves improvements in their solubility and dissolution (%) in solubilizer. In the present study, the pH-independent cilostazol (CLT) was formulated for enhanced solubility and dissolution (%) and for maintaining stability with meglumine by the solid dispersion (SD) technique. Methods The CLT formulations were prepared with weak acid or weak base by solvent evaporation method. Moreover, the physical properties of the optimal SD formulation that were evaluated were thermal property, crystallinity, and drug-excipient interaction. Results Based on the pre-dissolution test, meglumine and Aerosil (R) 200 were selected as the weak base and carrier, respectively. The SD1 formulation (CLT:meglumine:Aerosil (R) 200 at 1:1:0.5, w/w) enhanced the dissolution (%) of CLT in distilled water/pH 1.2/pH 6.8 buffer by 1.20-/1.13-/1.18-fold, respectively, compared with those of Pletal (R). Moreover, SD1 formulation was stable at room temperature for 3 months. A slight change in the crystallinity of CLT was observed in the SD1 formulation, which may be due to intermolecular interaction between CLT and meglumine. Conclusions The SD1 formulation showed improved dissolution (%) and might improve the bioavailability and efficacy of CLT.