Improvement in the Physicochemical Properties of Ketoconazole through Complexation with Cyclodextrin Derivatives

Highly-soluble cyclodextrin derivatives, such as hydroxypropyl--cyclodextrin(HP--CD) and methyl--cyclodextrin (MEB), were tested as solubilizingagents for ketoconazole, with the aim of improving the physicochemical andbiopharmaceutical properties of this lipophilic imidazole antifungal agent. Productswere prepared in four molecular ratios by physical mixing, kneading and spray-dryingmethods. The kneaded products in a ratio of 1:2 and the spray-dried products exhibitedthe highest dissolution rates. The phase solubility diagrams of ketoconazole with thesecyclodextrins at 25 °C in water and in simulated intestinal medium wereconstructed. A solubility diagram of A_L type was obtained with HP--CD, and one of A_P type with MEB. The complexes were characterized by thermal methods(DSC, TG, DTG and DTA). Multicomponent systems were prepared with tartaric acid.The effects of water-soluble polymers, e.g., polyvinylpyrrolidone, on the aqueous solubility of ketoconazole were investigated. Particle size distribution, surface area, partition coefficient, heat of dissolution and wettability studies were also carried out. The formation of inclusion complexes was observed by means of thermoanalytical studies.