Effects of lipid composition on the transcorneal penetration of liposomes containing disulfiram, a potential anti-cataract agent, in the rabbit.

We previously demonstrated that topical treatment with disulfiram (DSF) prevented the development of cataracts in sodium selenite-injected rat pups. In biological systems, DSF is rapidly reduced to diethyldithiocarbamate (DDC), a potent antioxidant. In this study, we investigated the effect of altering the lipid composition of liposomes containing DSF on the transcorneal transit of DDC. Liposomes containing DSF were prepared with various molar ratios of dimyristoylphosphatidylcholine (DMPC), dipalmitoylphosphatidylcholine (DPPC) and cetylpyridinum chloride (CPC) by reverse-phase evaporation. Liposomes with a DMPC to DPPC molar ratio of 5:5, examined by differential scanning calorimetry, had the highest enthalpy of transition and the presence of one molar ratio of CPC further enhanced the enthalpy value. The addition of bovine serum albumin or a homogenate of rabbit cornea to the incubation buffer resulted in the release of DDC, but not DSF from the liposomes. The amount of DDC present in the aqueous humor of rabbit eyes following topical administration increased with increase in DMPC to DPPC ratios and was also enhanced by the addition of CPC to the liposomes. The results of this study suggest that liposome formulations are effective for transcorneal drug delivery of anticataract agents such as DSF. DSF in liposomes consisting of DMPC, DPPC, and CPC with a molar ratio of 8:2:1 may be a potential drug formulation for the prevention and/or treatment of cataracts.