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Sodium ascorbyl phosphate in topical microemulsions
Polona Spiclin1, Miha Homar, Andreja Zupancic-Valant
1Faculty of Pharmacy, University of Ljubljana, Askerceva 7, 1000, Ljubljana, Slovenia.
Sodium ascorbyl phosphate, a stable vitamin C derivative, shows enhanced skin delivery via microemulsions. These systems provide sustained release, improving antioxidant efficacy for topical applications.
Area of Science:
- Cosmetic Science
- Pharmaceutics
- Materials Science
Background:
- Sodium ascorbyl phosphate (SAP) is a stable, hydrophilic vitamin C derivative used in skincare for its antioxidant properties.
- Topical delivery requires SAP conversion to ascorbic acid via enzymatic action in the skin.
- Microemulsions offer potential as advanced carrier systems for enhanced topical delivery.
Purpose of the Study:
- To evaluate oil-in-water (o/w) and water-in-oil (w/o) microemulsions as carrier systems for topical sodium ascorbyl phosphate delivery.
- To assess the stability and release characteristics of SAP within these microemulsion formulations.
- To optimize microemulsion viscosity for effective topical application.
Main Methods:
- Formulation of o/w and w/o microemulsions with identical ingredients.
- Stability assessment of SAP within both microemulsion types.
- Rheological characterization to determine optimal thickening agents (colloidal silica for w/o, xanthan gum for o/w).
- In vitro drug release studies to evaluate the influence of formulation and SAP location.
Main Results:
- SAP remained stable in both o/w and w/o microemulsions, irrespective of its location.
- Optimized microemulsions were achieved using 4.00% colloidal silica (w/o) and 0.50% xanthan gum (o/w).
- Incorporation into the internal aqueous phase resulted in sustained in vitro release profiles.
- Thickening agents and SAP location significantly influenced drug release.
Conclusions:
- Microemulsions are effective and stable carrier systems for the topical delivery of sodium ascorbyl phosphate.
- Formulation parameters, including thickening agents and SAP localization, modulate drug release kinetics.
- These findings support the use of microemulsions for enhancing the efficacy of topical vitamin C derivatives.
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