Development of a non-surfactant parenteral formulation of miconazole by the use of cyclodextrins

Miconazole is an antimycotic drug exhibiting a very poor water solubility (B1.03 mg:ml). It has been shown that cyclodextrins (CDs) are able to form inclusion complexes with miconazole and that they are able to increase its aqueous solubility. Miconazole is a weak base whose solubility depends of the pH. The purpose of this study was to investigate the influence of both CDs and different acids on the solubility of miconazole. It was found that a synergistic effect existed between CDs and different acids. The combination of hydroxypropyl-bCD (HP-bCD) (100 mM) or sulfobutylether 7-bCD (SBE7-bCD) (50 mM) and lactic acid (50 mM) allowed to dissolve more than 10 mg of miconazole per ml. NMR studies confirmed the formation of an inclusion complex miconazole–CD in an acidic medium. It was also shown by the NMR studies that the complex formed was a 1:1 complex. These results demonstrate that it is possible to develop a parenteral aqueous solution of miconazole without surfactant.