Evaluation of Liposomal and Conventional Amphotericin B in Experimental Fungal Keratitis Rabbit Model

PURPOSE: We evaluate the efficacy of liposomal amphotericin (Fungisome) compared to conventional amphotericin (AMB) for the treatment of fungal keratitis (FK) in an experimental rabbit model. METHODS: FK was induced in 48 New Zealand White rabbits using Aspergillus flavus and Candida albicans (24 rabbits each). Rabbits were divided into four groups: 0.1% and 0.05% Fungisome-, and 0.1% AMB-treated groups, and one untreated control group. Clinical scores were recorded throughout the study while fungal burden was estimated by corneal button culture on day 19 (study endpoint). RESULTS: A statistically significant improvement in clinical score was seen on day 11 in the 0.1% and 0.05% Fungisome versus untreated groups (13.91 and 14.4 vs. 19.3; P < 0.001) in the A. flavus model, and on day 9 in the 0.1% Fungisome-treated versus untreated groups (12.96 vs. 14.2; P = 0.006) in the C. albicans model. At endpoint, the mean clinical scores of the untreated controls, and the 0.1% and 0.05% Fungisome-, and 0.1% AMB-treated groups were 20 ± 1.4, 5.33 ± 1.85, 9.66 ± 2.41, and 8.16 ± 1.95, respectively, in the A. flavus model and 15.85 ± 1.87, 3.08 ± 1.31, 4.21 ± 1.370, and 4.13 ± 1.38, respectively, in the C. albicans model. Conjunctival hyperemia score was higher in the 0.1% AMB- versus 0.1% Fungisome-treated groups (1.33 vs. 0.5, P = 0.452). Lowest fungal burden in both models was seen in the 0.1% Fungisome-treated groups. CONCLUSIONS: Clinical improvement was observed with Fungisome relative to untreated controls. However, no statistically significant differences in outcomes were observed between animals treated with Fungisome and AMB. Although the results are encouraging, future studies in humans are warranted. TRANSLATIONAL RELEVANCE: FK is a leading cause of corneal blindness and is on the rise especially in developing countries. Despite the availability of various antifungal agents, heterogeneous treatment outcomes are seen due to lack of a standardized treatment regimen for FK. Although the use of liposomal AMB has been substantiated by clinical evidence in systemic infections, to our knowledge there are no in vivo studies evaluating the role of topical liposomal versus conventional formulation in FK. Our study investigated the efficacy and toxicity profile of liposomal versus conventional formulation of AMB in an experimental rabbit FK model.