Sustained release of niridazole from silicone rubber implants for the treatment of Schistosoma mansoni infections.

Niridazole was incorporated into silicone rubber implants to investigate the potential of a sustained release of the drug in the therapy of murine schistosomiasis mansoni. The infected animals (200 cercariae for 6 weeks) were randomly divided into three groups: one group received silicone rubber implants containing 50% by weight niridazole; a second group received blank silicone rubber implants with no drug; and the third group received no implants. Mortality 4 weeks later was in excess of 80% for animals with no implants or with the blank silicone rubber implants. In contrast, 10% mortality was observed in the mice receiving the niridazole-silicone rubber implants over a 10-week period. The worm burden in the niridazole-silicone rubber implant group was reduced at 10 weeks post implantation by 77%.