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Using pH abnormalities in diseased skin to trigger and target topical therapy

Rizi, K., Green, R. J., Donaldson, M. X. and Williams, A. C. ORCID: (2011) Using pH abnormalities in diseased skin to trigger and target topical therapy. Pharmaceutical Research, 28 (10). pp. 2589-2598. ISSN 0724-8741

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To link to this item DOI: 10.1007/s11095-011-0488-4


Abstract Purpose: The pH discrepancy between healthy and atopic dermatitis skin was identified as a site specific trigger for delivering hydrocortisone from microcapsules. Methods: Using Eudragit L100, a pH-responsive polymer which dissolves at pH 6, hydrocortisone-loaded microparticles were produced by oil-in-oil microencapsulation or spray drying. Release and permeation of hydrocortisone from microparticles alone or in gels was assessed and preliminary stability data was determined. Results: Drug release from microparticles was pH-dependent though the particles produced by spray drying also gave significant non-pH dependent burst release, resulting from their porous nature or from drug enrichment on the surface of these particles. This pH-responsive release was maintained upon incorporation of the oil-in-oil microparticles into Carbopol- and HPMC-based gel formulations. In-vitro studies showed 4 to 5-fold higher drug permeation through porcine skin from the gels at pH 7 compared to pH 5. Conclusions: Permeation studies showed that the oil-in-oil generated particles deliver essentially no drug at normal (intact) skin pH (5.0 – 5.5) but that delivery can be triggered and targeted to atopic dermatitis skin where the pH is elevated. The incorporation of these microparticles into Carbopol- and HPMC-based aqueous gel formulations demonstrated good stability and pH-responsive permeation into porcine skin.

Item Type:Article
Divisions:Life Sciences > School of Chemistry, Food and Pharmacy > School of Pharmacy > Pharmaceutics Research Group
Interdisciplinary centres and themes > Chemical Analysis Facility (CAF)
ID Code:21364
Publisher:Springer Verlag


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