RESUMO
Oxamniquine [OXQ] is one of schistosomicide specific for Schistosoma mansoni [S. mansoni] infection. The aim of this work was to encapsulate OXQ into a liposome. These liposomal formulations in order to exhibit long term prophylactic effect against S. mansoni. It was found that OXQ exhibited marked chemoprophylaxis effect when encapsulated in negatively charged liposomes. Pharmacokinetically, OXQ liposomes are perfectly targeted to the liver whereby they release oxamniquine in minute amounts over extended periods in the proximate of schistosomules, maturing in liver sinusoids. All animal groups were injected with either free oxamniquine, OXQ free liposomes or OXQ liposomes encapsulated, one, two or three months before infection by S. mansoni cercariae and were sacrificed 6 weeks post infection. It was found that OXQ liposomes had moderate normalization effect on liver enzymes, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and gamma glutamyl transferase in serum. Oxamniquine liposomes normalized A/G ratio and decreased the liver granuloma diameters. Infection increased the IgE and IgGl level, treatment with OXQ liposomes increased the level of IgG1 when given one or two months before infection, while free OXQ reduced IgG1 when given one month before infection and no significant change when given two months before infection. Treatment with different formulations to S. mansoni infected mice produced a significant decrease in IgE level after one and two months protection, while in normal animals there was an increase in IgG1 level after one month and no significant change after two months protection. So, it was concluded that OXQ in liposomal formulations is more efficient and safe than free drug in the protection against S. mansoni infection