Evaluation of hydrophilic permeant transport parameters in the localized and non-localized transport regions of skin treated simultaneously with low-frequency ultrasound and sodium lauryl sulfate

✍ Scribed by Joseph Kushner IV; Daniel Blankschtein; Robert Langer

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 290 KB
• Volume: 97
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.21028

✦ Synopsis

The porosity (e), the tortuosity (t), and the hindrance factor (H) of the aqueous pore channels located in the localized transport regions (LTRs) and the non-LTRs formed in skin treated simultaneously with low-frequency ultrasound (US) and the surfactant sodium lauryl sulfate (SLS), were evaluated for the delivery of four hydrophilic permeants (urea, mannitol, raffinose, and inulin) by analyzing dual-radiolabeled diffusion masking experiments for three different idealized cases of the aqueous pore pathway hypothesis. When e and t were assumed to be independent of the permeant radius, H was found to be statistically larger in the LTRs than in the non-LTRs. When a distribution of pore radii was assumed to exist in the skin, no statistical differences in e, t, and H were observed due to the large variation in the pore radii distribution shape parameter (3 A ˚to infinity). When infinitely large aqueous pores were assumed to exist in the skin, e was found to be 3-8-fold greater in the LTRs than in the non-LTRs, while little difference was observed in the LTRs and in the non-LTRs for t. This last result suggests that the efficacy of US/SLS treatment may be enhanced by increasing the porosity of the non-LTRs.