Comparison of immunomodulatory effects of free and liposomal levamisole administered intraperitoneally to rats

This study aimed to compare the effects of immunomodulatory treatment of rats with free and liposomal levamisole. Liposomes were freshly prepared and administered intraperitoneally to animals after characterization studies. The study was divided into Experiment 1 and Experiment 2. Experiment 1 involved daily administration at immunomodulating doses (2.5 mg/kg; IP) for three days, followed by a three-day break and further daily administration at immunomodulating doses (2.5 mg/kg; IP) for three days. Experiment 2 involved weekly administration at immunomodulating doses (2.5 mg/kg; IP) for four weeks. Immunomodulatory parameters, IL-5, IL-10, TNF-α, and IL-1β, were compared between free levamisole and liposomal levamisole formulations. No difference in TNF-α was found between the groups in Experiment 1 and Experiment 2. In Experiment 1, the free levamisole group showed higher values of IL-1β than did liposomal and control groups. IL-1β values in Experiment 2 were higher in the control group than in the free levamisole group. IL-5 values in Experiment 2 were higher in the control group than in the free levamisole group. In Experiment 1, IL-10 values were higher in the liposomal levamisole group and in the control group than they were in the free levamisole group. Thus it was determined that free and liposomal forms of levamisole, which have been found to have immunomodulatory effects in different animal species in many studies, also showed such effects in rats. It was concluded that studies on other animal species and other doses are needed to obtain more detailed information about the immunomodulatory effects of free and liposomal levamisole.