Assessment of a liposomal formulation of ivermectin in rabbit after a single subcutaneous administration

Ivermectin is a member of the macrocyclic lactone family widely used in livestock, pets, and humans as a potent parasiticide. Slight differences in formulation may change the plasma kinetics and efficacy of these compounds. The aim of the study is to evaluate the ability of a liposomal formulation of ivermectin to generate an efficient exposure of the animal to the drug. Ten rabbits were subcutaneously administered with 0.3 mg kg(-1) of ivermectin using Ivomec (n=5) or a liposomal formulation (n=5). The areas under serum concentration-time curve were similar after both treatments, indicating the same bioavailability for the two formulations. However, the liposomal formulation gave a higher C(max) value (33.33 ng ml(-1)) compared with Ivomec (20.82 ng ml(-1)) and a significantly faster absorption as indicated by the T(max) of 0.23 days compared with 1.13 days for the Ivomec formulation. The use of liposomal formulation shows promise as this system improves the efficacy of ivermectin and related drugs.