Physico-chemical characteristics of methotrexate-entrapped oleic acid-containing deformable liposomes for in vitro transepidermal delivery targeting psoriasis treatment.

This study aimed to investigate the physico-chemical characteristics and in vitro permeability of methotrexate (MTX)-entrapped deformable liposomes prepared from phosphatidylcholine (PC) and oleic acid (OA), comparing with those of MTX-entrapped conventional liposomes prepared from PC and cholesterol (CH). Two formulations of MTX-entrapped PC2:CH1 and PC9:CH1 liposomes and one formulation of MTX-entrapped PC2.5:OA1 liposomes were prepared. The size, size distribution, zeta potential, thermal properties, entrapment efficiency, stability, and in vitro permeability across a porcine skin of the MTX-entrapped liposomes were evaluated. All liposome formulations showed a narrow size distribution with the size range of 80-140 nm which is appropriate for the skin permeability. The percentage of MTX loading, entrapment efficiency and the stability of MTX-entrapped PC2:CH1 and PC9:CH1 liposomes were slightly higher than those of MTX-entrapped PC2.5:OA1 liposomes. However, the MTX-entrapped PC2.5:OA1 liposomes enhanced the skin permeability characterized by the higher concentration and flux of MTX diffused across or accumulated in the epidermis and dermis layers of porcine skin. The enhanced permeability of MTX-entrapped PC2.5:OA1 liposomes was explained by 2 mechanisms: (1) the deformable and elasticity characteristics of OA-containing liposomes and (2) a property as a skin penetration enhancer of OA. This suggested that the PC2.5:OA1 deformable liposome was one of promising candidates to enhance the permeability of MTX for the treatment of psoriasis.