Chitosan in the treatment of dry eye

Abstract

Abstract Purpose To demonstrate the safety and efficacy of a new eye drop formulation containing a novel thiolated biopolymer, namely chitosan‐N‐acetylcysteine, in a number of pre‐clinical tests. It is postulated that interaction between thiol groups of the topically applied chitosan‐N‐acetylcysteine and cysteine‐rich mucin (MUC5AC) increases polymer residence time on the ocular surface and tear film stability. Methods The efficacy of isotonic and buffered chitosan‐N‐acetylcysteine eye drops was evaluated in two different dry eye mouse models. The dosage dependent ocular residence time and biodistribution were investigated in a rabbit model using microPET technology. Long‐term irritation and delayed‐type hypersensitivity tests with chitosan‐N‐acteylcysteine eye drop formulation were conducted in rabbits. Results In both dry eye studies mice treated with chitosan‐N‐acetylcysteine showed decreased expression of ocular surface mRNA of IL‐β, IL‐10, IL‐12α, and TNF, indicating that the formulation may have protective ocular surface properties. The residence time of chitosan‐N‐acetylcysteine eye drops on the ocular surface of rabbits was increased (detection up to 22h). Results of a long‐term ocular irritation study in rabbits demonstrate that the novel formulation is well tolerated and non‐irritant to the eye. Conclusion Based on the promising pre‐clinical study results both in terms of efficacy and safety a clinical phase 1 trial is scheduled in the near future. Commercial interest