Chloroquine blood levels after administration of the liposome-encapsulated drug in relation to therapy of murine malaria.

In a previous report (P. A. M. Peeters, C. W. E. M. Huiskamp, W. M. C. Eling, and D. J. A. Crommelin. Parasitology, 1989, in press) an increase in therapeutic and prophylactic potential was found when chloroquine (CQ) was encapsulated in fluid-state liposomes (lipCQ) and tested in Plasmodium berghei-infected mice in comparison to intraperitoneal (i.p.) administration of the free drug. In this study, the same model was used to demonstrate that encapsulation of CQ into gel-state liposomes further increased the preventive and therapeutic effect considerably. CQ determinations in whole blood, plasma, and red blood cells (RBC) after i.p. administration of fluid- or gel-state lipCQ revealed a prolonged availability of the drug in comparison to administration of free CQ. The CQ concentrations were related to the CQ levels needed for prevention or therapy of Plasmodium berghei infections in mice.