Chemoprophylaxis of Schistosomiasis Using Liposome Encapsulated Oxamniquine

Abstract Oxamniquine liposomes with different compositions and surface charges were prepared by the chloroform-film method. The amount of oxamniquine entrapped was estimated and found to range from 1 to 23.09% of the initial amount of drug used for preparation of the liposomes depending on the suvace charge of liposomal vesicles. Negatively charged liposomes exhibited the highest percentage entrapment viz., 23.09%. The maximum oxamniquine entrapment was achieved in liposomes prepared from phospholipids molar ratio (7:4.1). The liposome formulations were characterized by her light scattering technique, particle size analysis and rheological characterization. In vitro release kinetics of oxainquine liposomes reveal that the percentage drug release is suvace charge dependent and irrelevant to the molar ratio. The results of organ, liver and spleen, targetting of oxamniquine liposomes in mice reveal that after 7 days of (S.C.) injection the amount of oxamniquine retain more than three times (7:4:1) more than two times (7:6) and nearly double (7:6:1) the amount of drug retained by injection of the free drug. Afrer 14 days of (S.C.) injection of oxamniquine liposomes, negatively charged liposomes of the highest cholesterol content exhibit better drug retention than neutral liposomes and no free drug detected in these organs, after this period of time. The chemoprophylactic eflect of free and oxamniquine liposome formulations was estimated using female Swiss mice injected 7, 15, 30, and 60 days before larval infection. for 7 days chemoprophylactic study liposomes encapsulation show more eficient prophylaxis. In the 15 days study the percentage worm count reduction is in the following order: 7:4:1 (-ve) (68.8%) > 7:2:1 (-ve) (66%) > 7:2 (34.4%) > free oxamniquine (0.00%). for the 30 day study the negatively charged liposome 7:4:1 exhibited a signifcant reduction of worm burden. for the 60 days, the liposomes 7:6 produced better chemoprophyhis than 7:6:1 (-ve). The results of T-cell and B-cell responses against soluble adult warm proteins reveal that oxamniquine, when encapsulated in liposomes, stimulate the immune system of mice against the worms of S. mansoni.