Antischistosomal Efficacy Study on Praziquantel, Its Alkaline Hydrolysis and the Sun-Decomposed Products

Praziquantel (PZQ) administered in a dose of 40 mg /kg body weight to S. mansolli infected albinomice, was not active enough to cause a significant reduction in the mean worm recovery 16.6 %. Thereduction caused by the alkaline hydrolysis product, (PZQ .. HP) 28.6 %, and the sun decomposedproduct, (PZQ-SDP) 47.6 % of PZQ suggested higher antischistosomal activity of these two productscompared to PZQ. 111ere were no significant differences in liver and intestine tissue egg count can iedon the infected-treated groups, and the infected-untreated group. The granulomas observed in thelivers of the experimentally S. mansoni infected-untreated mice were mainly cellular existing within the portal tract and subcapsular parenchyma. Schistosome pigments were observed in the Kutter cellwith thickening of the portal tract. The vascular lesions comprised granulomatous occlusions,periphelebitis, perivascular cuffing of the central vein and sinusoidal dilatation. The hepatic histopathological changes obscrved in the PZQ, and the PZQ-HP-treated groups were similar,characterized by the scattering of the granulomas in the portal tract and intralobular parenchyma. Thevascular lesions in these groups (PZQ and (PZQ-HP)) comprised periphelebitis of some portalradicles, granulomatous occlusions and rarely the perivascular cuffing of the central vein. Theseresults indicated comparable efficacy of the two compounds. The granulomas of the PZQ-SDPtreated group were found distributed between the portal radicles and parenchyma in equal mannerwith central egg and/or shell or necrosis. Schistosome pigments were less intense than in the infected-untreated mice with infrequent leucocytic foci, pcrivascular cuffing of the central vein andperiphlebitis of the portal vein. The number of granulomas in the SP-treated group was less than in theinfected-untreated mice with greater size whereas that of PZQ- and PZQ-HP-treated groups werecomparable in number and size but significantly different in number (p= 0.01) in comparison with theinfected-untreated mice. These variations were interpreted and justified. Despite of the death of halfthe group treated with PZQ-SDP compound within the first and second week post treatment; therewere no signs of hepatotoxic effects as revealed by the histopathological study conducted at ourlaboratories.