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.