Suppository formulations as a potential treatment for nephropathic cystinosis.

Nephropathic cystinosis is a rare autosomal recessive disease characterised by raised lysosomal levels of cystine in the cells of all the organs. It is treated by the 6-h oral administration of the aminothiol, cysteamine, which has an offensive taste and smell. In an attempt to reduce this frequency and improve the treatment, cysteamine-containing polyethylene glycol suppositories were prepared and evaluated for dissolution and stability. The results demonstrated that cysteamine release was complete after 30 min, and that there was a uniform drug distribution within the formulations. Twelve-month stability tests highlighted a potential incompatibility among some excipients, although stability was demonstrated for the cysteamine suppositories up to 6 months. These suppositories may provide a useful alternative to the current oral therapy for cystinosis.