Percutaneous penetration of liposomes using the tape stripping technique

The reservoir capacity of the stratum corneum was studied by topical application of sodium fluorescein encapsulated in vesicles in order to elucidate the mechanism involved in the (trans)dermal transport of drugs when vesicles are applied to the skin. The penetration profile of sodium fluorescein in the different strips was found to be logarithmic with both the constant and the slope of the regression curves, accounting for the superficial non-penetration content and for the penetration rate inside the stratum corneum, respectively. The results show a small but significantly enhanced penetration of these vesicle structures for the release of hydrophilic substances. Moreover, similar values obtained when the same liposomes with a varying encapsulation content were applied could lend support to the penetration mechanism where the vesicle enhancement is mainly due to stratum corneum structural modification.