PERCUTANEOUS PENETRATION OF LIPOSOMES USING THE TAPE STRIPPING TECHNIQUE

The reservoir capacity of the stratum corneum was studied by topical a pplication of sodium fluorescein encapsulated in vesicles in order to elucidate the mechanism involved in the (trans)dermal transport of dru gs when vesicles are applied to the skin. The penetration profile of s odium fluorescein in the different strips was found to be logarithmic with both the constant and the slope of the regression curves, account ing for the superficial non-penetration content and for the penetratio n rate inside the stratum corneum, respectively. The results show a sm all but significantly enhanced penetration of these vesicle structures for the release of hydrophilic substances. Moreover, similar values o btained when the same liposomes with a varying encapsulation content w ere applied could lend support to the penetration mechanism where the vesicle enhancement is mainly due to stratum corneum structural modifi cation.