Development and evaluation of LIPODEET, a new long-acting formulation of N, N-diethyl-m-toluamide (DEET) for the prevention of schistosomiasis

N, N-diethyl-m-toluamide (DEET) is a common and fairly safe active ingredie nt in many insect repellents. Our recent studies showed that when applied t o the skin, DEET has a potent anti-parasitic effect against Schistosoma man soni. However, the beneficial effects of DEFT lasted only for a few minutes , presumably due to its rapid absorption through the skin. In this study, w e evaluated different carrier formulations that prolong the activity of DEE T in the skin. Among the various formulations analyzed, DEET incorporated i nto liposomes (LIPODEET) appeared to prolong the activity of DEET for more than 48 hr after a single application. Furthermore, LIPODEET was found to b e minimally absorbed through the skin and loss due to washing off was limit ed. These findings thus suggest LIPODEET is a safe and long-acting formulat ion of DEET that is quite effective against schistosomiasis.