Objectives: Liposomes are reported as penetration enhancers for dermal and transdermal delivery. However, little is known about their percutaneous penetration and as to at which level they deliver encapsulated drugs. The penetration of multilamellar vesicles (MLVs) and small unilamellar vesicles (SUVs), in comparison to one of their lipid components, was investigated. Methods: Using the fluorescent lipid, Lissamine Rhodamine B-PE (R), as a constituent, MLV and SUV liposomes were prepared, tested, and R, MLV, or SUV were applied in vivo on the back of hairless mice. Absorption of each was evaluated at the levels of stratum corneum, living skin, and blood by fluorometry. Results: Penetration of the lipid R in stratum corneum in the nonliposomal form exceeded that in the liposomal form and only R penetrates the living skin in a statistically significant manner. No statistical significant absorption into blood was observed with either form. Conclusions: Liposomes size did not play an important role in penetration to stratum corneum. The lipid constituent in the nonliposomal form penetrated at higher rates into stratum corneum and living skin. Even though these liposomes entered stratum corneum, they were not significantly absorbed into viable skin or blood.
The non‐homogenous distribution and aggregation of carotenoids in the stratum corneum correlates with the organization of intercellular lipids in vivo
