Imidazolium ionic liquid as potential contact lens disinfectant inactivating cystic resistance forms from ACANTHAMOEBA keratitis

Resumo

Keratitis caused by Acanthamoeba spp. is a rare disease, although increasingly common, especially among contact lens users. The occurrence and the devastating effect of this disease are associated with the lack of care in cleaning and disinfecting lenses and their storage cases, as well as ineffective drugs to mainly eliminate the parasite’s cysts. This work evaluated the amoebicidal activity of the imidazolium salt 1-hexadecyl-3-methylimidazolium chloride (C16MImCl) against cysts of two characterized isolates from Acanthamoeba keratitis cases (MZ404337 and MZ404332). The inactivation of 100% of the cysts was achieved at a concentration of 7.81 μg/mL for MZ404337 and of 1.95 μg/mL for MZ404332, both at 24 h and 48 h of exposure time. In contrast, a commercial formulation of chlorhexidine did not cause any reduction in the viability of the cysts. Related to the cytotoxicity to human HaCaT cells, C16MImCl is biocompatible at the concentration required to inactivate cysts. This shows that C16MImCl is a promising disinfectant for contact lenses and surfaces.

KEY WORDS: 1-hexadecyl-3-methylimidazolium chloride; Acanthamoeba keratitis; cysts; chlorhexidine; cytotoxicity.