Improved yeast delivery of fluconazole with a nanostructured lipid carrier system

Despite the growing trends in the number of patients at risk for invasive fungal infections, management with current antifungal agents results in complications due to changes in the epidemiology and drug susceptibility of invasive fungal infections. In the present research fluconazole-loaded nanostructured lipid carriers were prepared using probe ultrasonication techniques and investigated the efficacy of the optimal formulation on a large number of Candida species. The morphology of the obtained nanostructured lipid carriers was characterized by transmission-electron microscopy. The minimum inhibitory concentrations (MIC) for the new formulations against strains of Candida were investigated using the Clinical and Laboratory Standards Institute document M27-A3 and M27-S4 as a guideline. The fluconazole-loaded nanostructured lipid carriers presented a spherical shape with a mean diameter, zeta potential and entrapment efficiency of 126.4 ± 15.2 nm, −35.1 ± 3.0 mV, and 93.6 ± 3.5%, respectively. The drug release from fluconazole-loaded nanostructured lipid carriers exhibited burst-release behavior at the initial stage followed by sustained release over 24 h. Using a new formulation of fluconazole led to a significant decrease in MICs for all Candida groups (P < 0.05). Furthermore, C. albicans isolates showed more susceptibility to fluconazole-loaded nanostructured lipid carriers than C. glabrata and C. parapsilosis (P < 0.05). The MIC50 drug concentration was obtained as 0.0625, 0.031 and 0.25 μg/ml for fluconazole-resistant strains of C. albicans, C. glabrata, and C. parapsilosis, respectively. In conclusion, a novel delivery system which can be used as part of a strategy to improve the antifungal activity of fluconazole against various Candida strains with different susceptibilities to conventional formulations of fluconazole was evaluated.