The active substance, halofuginone, is an antiprotozoal agent of the quinazolinone derivatives group (nitrogenous polyheterocycles). Halofuginone lactate (RU 38788) is a salt whose antiprotozoal properties and efficacy against Cryptosporidium parvum have been demonstrated both in in vitro conditions and in artificial and natural infections. The compound has a cryptosporidiostatic effect on Cryptosporidium parvum. It is mainly active on the free stages of the parasite (sporozoïte, merozoïte). The concentrations to inhibit 50 % and 90 % of the parasites, in an in vitro test system, are IC50 less than 0.1μg/ml and IC90 of 4.5μg/ml respectively.

The bioavailability of the drug in the calf, following single oral administration, is about 80 %. The time necessary to obtain the maximum concentration Tmax is 11 hours. The maximum concentration in plasma Cmax is 4 ng/ml. The apparent volume of distribution is 10 l/kg. The plasmatic concentrations of halofuginone after repeated oral administrations are comparable to the pharmacokinetic pattern after single oral treatment. Unchanged Halofuginone is the major component in the tissues. Highest values have been found in the liver and the kidney. The product is mainly excreted in the urine. The terminal elimination half-life is 11.7 hours after intravenous administration and 30.84 hours after single oral administration.