Using pH abnormalities in diseased skin to trigger and target topical therapy
Khalida Rizi1, Rebecca J Green, Michael X Donaldson
1Reading School of Pharmacy, University of Reading, Whiteknights, P.O. Box 226, Reading, RG6 6AP, UK.
Pharmaceutical Research
|May 27, 2011
Summary
Hydrocortisone microcapsules are designed to release medication specifically on atopic dermatitis skin, leveraging its higher pH. This targeted delivery system shows promise for enhanced treatment efficacy.
Area of Science:
- Pharmaceutical Sciences
- Dermatology
- Materials Science
Background:
- Atopic dermatitis (AD) skin exhibits a distinct pH difference compared to healthy skin.
- This pH discrepancy presents an opportunity for targeted drug delivery systems.
Purpose of the Study:
- To develop pH-responsive microcapsules for targeted hydrocortisone delivery.
- To investigate the pH-triggered release and permeation of hydrocortisone from microcapsules.
Main Methods:
- Hydrocortisone-loaded microparticles were fabricated using Eudragit L100, a pH-responsive polymer, via oil-in-oil microencapsulation and spray drying.
- Drug release and permeation studies were conducted in vitro using porcine skin, with formulations incorporated into Carbopol and HPMC gels.
- Preliminary stability assessments were performed.
Main Results:
- Microparticle drug release demonstrated pH-dependency, with spray-dried particles exhibiting some non-pH-dependent burst release.
- pH-responsive release was sustained when microparticles were formulated into Carbopol and HPMC gels.
- In vitro permeation studies showed a 4- to 5-fold increase in hydrocortisone permeation through porcine skin at pH 7 compared to pH 5.
Conclusions:
- Oil-in-oil microparticles effectively minimize drug release at normal skin pH (5.0-5.5).
- Drug delivery is triggered and targeted to elevated pH conditions characteristic of atopic dermatitis skin.
- The microparticle-gel formulations exhibited good stability and pH-responsive permeation, indicating potential for AD treatment.
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