Efficacy of Amphotericin B in Corneal Preservation Media after Extended Frozen Storage

Abstract

Purpose:To investigate the antimycotic activity of amphotericin B deoxycholate that has been previously frozen for 28 days before supplementation of Optisol-GS.Methods:Triplicate Optisol-GS samples were inoculated with 106colony-forming units (CFU) of Candida albicans. Each set of triplicate cultures was supplemented with 2.5 g/mL of amphotericin B that was either freshly resuspended and never frozen, frozen overnight at-20°C and thawed, or frozen at-20°C for 4 weeks and thawed. The cultures were stored at 4°C, with aliquots taken at 0, 6, 24, and 72 hours for quantification. The efficacy of each preparation of amphotericin B in reducing C. albicans growth was assessed at these time points.Results:Six hours after antifungal supplementation, there was a 1.33 log10CFU reduction with freshly resuspended amphotericin B, compared with a 1.31 log10reduction with amphotericin B that was frozen overnight (P = 0.20) and a 1.18 log10reduction with amphotericin B that was frozen for 4 weeks (P = 0.05). After 72 hours, there was a 2.72 log10CFU reduction with freshly resuspended amphotericin B, a 2.64 log10CFU reduction with amphotericin B that was frozen overnight (P = 0.45), and a 2.18 log10CFU reduction with amphotericin B that was frozen for 4 weeks (P = 0.05).Conclusions:Previously frozen amphotericin B remains highly effective against C. albicans. Optisol-GS supplemented with 2.5 g/mL amphotericin B that was frozen for 4 weeks at-20°C resulted in >90% CFU reduction by 6 hours and >99% reduction by 72 hours.