[Cysteamine ophthalmic hydrogel for the treatment of ocular cystinosis]

Ocular cystinosis is a rare disease characterised by the deposit of cystine crystals on the corneal surface, which hinder patients' eyesight. Oral cysteamine is given as cysteamine; however, it does not reach the cornea due to the lack of corneal vascularization making necessary its  administration by the topical ocular route. The aim of the present study is to  determine the stability of an ophthalmic hydrogel of cysteamine, which can be  potentially prepared at hospital pharmacy departments, under different preservation conditions during a follow-up of 30 days. Different physical  and chemical parameters were evaluated: osmolality, pH and  cysteamine concentration, which has been measured by a method of ultra  performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS).  Descriptive assays were also performed, such as transparency measurement and  microbiological assays in order to verify its sterility. The obtained results  allow us to conclude that the cysteamine hydrogel is stable during 30 days,  being recommendable its preservation in refrigerated conditions.