Corticosteroid dermal delivery with skin-lipid liposomes

Skin-lipid liposomes were prepared to improve corticosteroid dermal delivery and hence, their therapeutic effectiveness. Skin-lipid liposome formulations, and for comparison also phospholipid based liposomes, were prepared by hydrating a thin lipid film followed by extrusion through polycarbonate filters. The liposomes obtained were unilamellar vesicles with a mean size of 100 nm and a narrow size distribution. The steroidal anti-inflammatory drugs selected were situated in the bilayer structures of the vesicles. Skin-lipid liposomes provided the highest drug disposition within the deeper skin layers, i.e. in the epidermis and dermis. The therapeutic effectiveness was evaluated by measurement of the blanching effect following UV-induced erythema. Skin-lipid liposomes showed a 6 and 1.3 times higher blanching effect than that obtained with a control formulation ointment and the phospholipid-based liposome formulation, respectively. Skin-lipid liposomes also produced a reduction in drug levels in the blood and urine. These findings were supported by the body distribution of the drugs in guinea pigs after topical treatment. In particular, skin-lipid liposomes provided a corticosteroid uptake in the thalamic region (site of corticosteroid collateral effects) 5.1 times lower than the control formulation. Skin-lipid liposomes appeared to be a suitable corticosteroid delivery system, increasing the pharmacological effectiveness and reducing possible side effects.