Prophylactic Activity of Suramin Complexes in ‘Surra’ (Trypanosoma evansi)

Abstract

SURAMIN, being acidic in reaction, forms insoluble precipitates—called suramin complexes—with other trypanocides which are basic compounds like antrycide dimethyl sulphate, ‘Berenil’ (di-(amidinophenyl)-triazene(-N-l:3)diaceturate), pentamidine, etc. Such combinations have been reported to have markedly reduced toxicity and considerably enhanced prophylactic activity. Williamson and Desowitz¹ reported maximum decrease of five- and three-fold in the toxicity of suramin complexes of antrycide and ‘Bereni’ respectively. They found that suramin–antrycide complex protected cattle against Trypanosoma vivax and T. congolense for at least 95–199 days at dose rates of 10–40 mg/kg of the antrycide content. Williamson² reported that rats were protected against T. congolense for 53 and 11 weeks with suramin complex of antrycide (201 mg/kg) and ‘Berenil’ (129 mg/kg body-weight) respectively as compared with 1½ weeks, 18 weeks and <4 weeks protection afforded by suramin (62.5 mg/kg body-weight), antrycide dimethyl sulphate (7.8 mg/kg body-weight) and ‘Berenil’ (50 mg./kg body-weight) respectively. Since then complexes of suramin have been widely experimented with in animal trypanosomiases in Africa. Suramin complexes of antrycide dimethyl sulphate and ‘Bereni’ were prepared after Williamson² and tried for their prophylactic activity against T. evansi.