The purpose of the study was to develop a stable, controlled release Amphotericin B ( Amph B) lyophilized mixed micelle (MM) formulation using hydrogenated soya phosphatidylcholine (HSPC) and bile salts in monomeric form and evaluate it for therapeutic performance and side effects. The MM formulations of Amph B were prepared using sodium deoxycholate (NDC)/sodium taurocholate (NTC)/sodium cholate (NC), and HSPC. The optimization of bile salt: HSPC ratio in the MM formulation was done using 24 factorial designs. MM formulations were lyophilized using sucrose as a cryoprotectant and analyzed for per cent micelle yield, per cent drug loading and per cent entrapment efficiency. Comparative in vitro diffusion studies, hemolytic activity, and minimum inhibitory concentration (MIC) of developed MM formulations and marketed formulation (Fungizone) were evaluated using cellophane membrane, human red blood cells and Candida albicans respectively. In vivo studies of MM formulations were also carried out on Candida albicans infected white albino rats and compared with Fungizone. The optimized molar ratio of bile salt: HSPC was found to be 8:11. Among all MM formulations prepared, NDC/ HSPC formulation found to have maximum per cent drug loading (4.96±0.8%), per cent entrapment efficiency (93.2±1.5%) and per cent micelle yield (96.4±1.4%). The in vitro drug diffusion studies of developed MM formulations show close to zero-order diffusion kinetics. All MM formulations show improved therapeutic index and reduced side effects compared to reference formulation Fungizone. The NDC/HSPC MM formulation was found to have least hemolytic activity, MIC and mortality rate at all dosage levels. Improved antifungal activity and reduced toxicity of Amph B solubilized in MM may be due to higher cellular uptake of the drug by fungal cells of infected tissues from MM formulations. Hence, Amph B MM formulation could be a safe and effective viable alternative in the treatment of systemic fungal infections.
Keywords: amphotericin b, mixed micelles, hemolytic activity, minimum inhibitory concentration, mortality, monomeric form
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