Miconazole nitrate-loaded microparticles for buccal use: immediate drug release and antifungal effect.

The aim of this study was to prepare and to evaluate Eudragit L100 and Gantrez MS-955 microparticles containing miconazole nitrate for buccal delivery. Microparticles were prepared by spray-drying method in order to achieve high encapsulation efficiency and increased drug solubility. The microparticles were obtained containing 10% and 20% (w/w) of drug:polymer ratio using Eudragit L100 (E10 and E20), Gantrez MS-955 (G10 and G20) or their combination (EG10 and EG20). The influence of formulation factors (drug:polymer ratio, type of polymer) on yield, encapsulation efficiency, particle size, Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction, differential scanning calorimetry, in vitro drug release and antifungal activity were investigated. Acceptable yield, micrometer-sized particles and drug-loading efficiencies higher than 89% were obtained. No change in FTIR assignments was recorded after the microencapsulation procedure. X-ray and differential scanning calorimetry studies revealed amorphous/non-crystalline formulations. Miconazole nitrate-microparticles provided a remarkable increase of dissolution rate for this drug. Miconazole nitrate and G10, G20, EG10, and EG20 microparticles were fitted to biexponential kinetic model while E10 and E20 microparticles were fitted to monoexponential kinetic model. The antifungal assay demonstrated that miconazole nitrate-loaded microparticles provided the same anti-Candida albicans activity of the pure drug. These results indicate that miconazole nitrate-loaded microparticles are feasible carriers for increased release of this antifungal drug at buccal environment.