Cysteamine ophthalmic hydrogel for the treatment of ocular cystinosis

Abstract

Ocular cystinosis is a rare disease characterised by the deposition on the corneal surface of cystine crystals that hinder the eyesight of patients. Oral cysteamine is administered as cysteamine bitartrate; however, due to the lack of corneal vascularization it does not reach the cornea and must be administered by the topical ocular route. The aim of the present study was to determine the stability of an ophthalmic hydrogel of cysteamine under different preservation conditions during a follow-up of 30 days. This hydrogel could be prepared in hospital pharmacy services.Several physical and chemical parameters were assessed: osmolality, pH, and cysteamine concentration, which was measured using an ultra-performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS) method. Descriptive tests were also performed, such as transparency measurements and microbiological assays in order to verify sterility. The results show that cysteamine hydrogel is stable over 30 days and should be preserved under refrigeration.