Ocular biodistribution of cysteamine delivered by a sustained release microsphere/thermoresponsive gel eyedrop.

The objective of the investigation was to determine the ocular biodistribution of cysteamine, a reducing agent used for treatment of cystine crystals in cystinosis, following topical administration of a sustained release formulation and traditional eyedrop formulation. To the right eye only, rabbits received a 50 µL drop of 0.44% cysteamine eyedrops at one drop per waking hour for 2, 6, 12, and 24 h.