VISCERAL LEISHMANIASIS IN THE BALB C MOUSE - A COMPARISON OF THE IN-VIVO ACTIVITY OF 5 NONIONIC SURFACTANT VESICLE PREPARATIONS OF SODIUM STIBOGLUCONATE/

Five non-ionic surfactants (Surfactants V - IX) were screened for thei r ability to produce vesicles for the delivery of sodium stibogluconat e. Mean vesicle diameter and antimony content were determined prior to in vivo assessment of antiparasitic activity in a mouse model of acut e visceral leishmaniasis. V/D suspensions (i.e. stibogluconate loaded vesicles kept in the hydrating drug solution) were more effective agai nst spleen, liver and bone marrow parasites than drug loaded vesicle s uspensions that had unentrapped drug removed. A Surfactant IX V/D susp ension was the most active antileishmanial preparation causing 74 +/- 10%, 99 +/- 1% and 38 +/- 8% suppression of liver, spleen and bone mar row parasite burdens respectively. Contrary to previous findings, a re duction in splenic and bone marrow parasite burdens was achieved using large vesicles (mean diameter > 800nm). The significance of these res ults is discussed.