Long-acting parasiticidal composition with improved bioavailability comprising an avermectin or milbemycin, plus a salicylanilide amp; a polymeric species

摘要

An injectable composition prepared for treating animals suffering from parasites, which parasites are known to be susceptible to at least one of the avermectins, milbemycins or salicylanilides, comprises a first parasiticidal agent selected from amongst the avermectins and the milbemycins, together with another parasiticidal agent selected from the salicylanilides in an amount such that the injectable composition delivers at least about 2.5 mg salicylanilide per kilogram live weight of the animal to be treated, in a physiologically tolerable solvent system suitable for injection, and an amount of a polymeric species that is effective to improve bioavailability of the salicylanilide parasiticidal agent over a period of treatment. H preferably comprises ivermectin in an amount of from 0.1 to 10%(w/v), a solvent selected from the group consisting of glycerol formal, propylene glycol, polyethylene glycol and combinations thereof, and a salicylanilide such as closantel. The polymeric species is preferably selected from the group consisting of polyvinylpyrrolidone and polyoxypropylene/polyoxyethylene block copolymers. The polymeric species improves the bioavailability of the salicylanilide as determined by blood plasma levels.