PURPOSEThe pH discrepancy between healthy and atopic dermatitis skin was identified as a site-specific trigger for delivering hydrocortisone from microcapsules.METHODSUsing 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.RESULTSDrug 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.CONCLUSIONSPermeation 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.

1987-05-01·Journal of International Medical Research4区 · 医学

A Double-Blind Comparison of 0.25% and 0.05% Desoxymethasone, 0.1% Betamethasone Valerate and 1% Hydrocortisone Creams in the Treatment of Eczema

4区 · 医学

ArticleOA

作者: Fairris, G. ; Morley, N. ; Joseph, D. N. ; Ashton, R. E. ; Catterall, M.

The efficacy and acceptability of 0.25% and 0.05% desoxymethasone, 0.1% betamethasone valerate and 1% hydrocortisone creams were compared in patients with eczema. A double-blind parallel group multi-centre design was employed in which 96 patients were recruited by four centres. Patients used one cream for a 3-week period and follow-up assessment visits were made at weekly intervals. Efficacy variables were: erythema/redness, scaling, itching and extent of area affected. These variables were assessed by both the investigator and the patient. The 0.25% desoxymethasone was the most effective treatment, producing the greatest degree of improvement in all clinical parameters, hydrocortisone was the least effective and 0.05% desoxymethasone was of intermediate effectiveness. The 0.1% betamethasone produced similar results to 0.25% desoxymethasone for half the assessments; for the other half the results were similar to 0.05% desoxymethasone. No adverse effects were reported during the study. The results are discussed in terms of physical properties of the vehicles and corticosteroid potency.

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