RESUMO
Triamcinolone is a steroidal anti-inflammatory drug widely used in the treatment of skin diseases. Liposomes are microscopic vesicles that composed of lipid bilayers enclosing aqueous compartments. In this study, different liposomal formulations encapsulated with triamcinolone were prepared and their anti-inflammatory effects were compared with a conventional topical ointment. In this study liposomes containing 0.1% triamcinolone were prepared by the fusion method using lecithin, cholesterol and penetration enhancers. Encapsulation efficiency was determined by UV spectrophotometry. Liposome size was examined by optical microscopy. The anti-inflammatory effect of liposomal formulations was evaluated by "xylene-induced ear edema" method in mice and then results were compared with a conventional topical ointment. Among different formulations only two formulations were stable and suitable regards to encapsulation efficiency, size, and the lack of triamcinolone precipitation. The first formulation did not have penetration enhancer and the second one contained a penetration enhancer. Liposome size was varied from 2 to 5 micron, and encapsulation efficiency in the first and second formulation was 80.33 +/- 3.51% and 90.50 +/- 2.78%, respectively. In vivo study showed that both conventional ointment and liposomal triamcinolone decrease ear edema compared to the control liposome [p<0.01]. The percent of edema inhibition [Mean +/- SEM] in comparison with control was 44% +/- 6.0, 71% +/- 6.4 and 78% +/- 5.4 for conventional ointment, first and second liposomal formulations respectively. The anti-inflammatory of liposomal formulations were significantly more than conventional triamcinolone ointment [p<0.05]. Results show that liposomal triamcinolone have more anti-inflammatory effect than conventional triamcinolone ointment. Thus, to provide the same effect as conventional triamcinolone ointment, the lower concentration of triamcinolone in liposome formulation is needed, this in turn will cause less side effects