all internal parasites of the host animal it was desired to obtain a parenteral formulation which also had high levels of activity against both internal and external parasites the instant formulation achieves the desired result as demonstrated in the following test a comparison of the efficacy of ivermectin when administered to cattle by means of the instant formulation or by an aqueous micelle formulation shows the superiority of the instant formulation particularly towards ectoparasites cattle that had been infected with ticks boophilus microplus were given a control placebo or equal doses of ivermectin via the formulation of example 1 or an aqueous micelle formulation the efficacy of the treatment was measured by counting the ticks in the manner described by wharton et al in australian journal of agricultural research 21 pages 985 1006 1970 the prolonged effects of the drug were observed by counting the ticks several times over a 4 week period with a constant natural exposure to tick infestation the test showed that to a statistically significant degree both formulations had fewer ticks than the controls at the end of the trial there were statistically significantly more ticks on the micelle treated cattle than on the cattle treated with the instant formulation thus demonstrating greater efficacy and duration of efficacy for the instant formulation the following examples are provided in order that the invention might be more fully understood they should not.