Effect of liposomes on percutaneous penetration of lipophilic materials

Abstract

Liposomes were prepared of two lipophilic drugs, dl-α-tocopherol nicotinate (TN) and the anti-inflammatory substance, L440. In the case of dl-α-tocopherol nicotinate liposomes, oleoyl-hydrolyzed animal protein (OHAP) was added in order to control the vesicle size. The skin penetration ability of both drugs from liposomal gels into human stratum corneum was determined in vivo by a stripping method and compared with conventional galenical formulations. The anti-inflammatory effect of the released L440 was examined in the ear edema model in mice. The penetration tests showed significantly higher absorption rates for both drugs after application of the liposomal preparations in comparison to other topical formulations. However, only a slight dependence of the extent of drug permeation into the stratum corneum on liposome diameter was observed. The pharmacological effect of L440 was investigated in the mouse ear edema test (Young et al., J. Invest. Dermatol., 80 (1982) 48–52; and J. Invest. Dermatol., 82 (1984) 367–371). No difference was found between the liposome preparation and an o/w base, whereas a w/o base yielded only a 50% reduction in edema.