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Vitamin A palmitate photostability and stability over time
M E Carlotti1, V Rossatto, M Gallarate
1Dipartimento di Scienza e Tecnologia del Farmaco, Universita degli Studi di Torino, 10125 Turin, Italy.
Journal of Cosmetic Science
|July 21, 2004
Summary
Encapsulated vitamin A palmitate systems, particularly nanocapsules and liposomes, offer superior protection against degradation from light, heat, and hydrolysis. Sunscreens and antioxidants further enhance vitamin A palmitate stability in hydrogels, improving its suitability for cosmetic formulations.
Area of Science:
- Cosmetic Science
- Materials Science
- Photochemistry
Background:
- Vitamin A palmitate is a crucial ingredient in skincare, but its stability is compromised by UV light, heat, and pH variations.
- Developing stable formulations is essential for effective delivery and product longevity in cosmetic applications.
Purpose of the Study:
- To evaluate the photostability and shelf-life of vitamin A palmitate in various formulations.
- To investigate the protective effects of encapsulation, sunscreens, and antioxidants on vitamin A palmitate degradation.
- To assess the impact of pH and storage conditions on formulation stability.
Main Methods:
- Vitamin A palmitate stability was tested in hydroxy ethyl cellulose hydrogels and O/W emulsions.
- Encapsulated systems (microcapsules, liposomes, nanocapsules) were evaluated for vitamin A palmitate protection.
- Photostability was assessed under UVA/UVB irradiation.
- Long-term stability was studied at different pH levels (4.0-8.0) and temperatures (25°C, 40°C).
- High-Performance Liquid Chromatography (HPLC) and rheological studies were employed for analysis.
Main Results:
- Encapsulated systems (Lipotec nanocapsules, Tagravit A1 microcapsules, Lipotec liposomes, phosphatidylcholine liposomes) protected vitamin A palmitate from hydrolysis and oxidation.
- Lipotec nanocapsules and phosphatidylcholine liposomes significantly improved vitamin A palmitate photostability.
- Sunscreens (3,4-methylbenzilidencamphor, butyl methoxy dibenzoylmethane) enhanced photostability in hydrogels.
- Butylated hydroxy toluene (BHT) protected against light-induced degradation and heat-induced degradation at pH 5.6 and 7.0.
- Formulation viscosity decreased after UV irradiation and prolonged storage, indicating degradation of excipients.
Conclusions:
- Encapsulation is a highly effective strategy for stabilizing vitamin A palmitate in cosmetic formulations.
- Specific encapsulated systems, like nanocapsules and liposomes, offer superior protection against degradation.
- Antioxidants and sunscreens can further enhance vitamin A palmitate stability, particularly against photodegradation.
- Formulation excipients may degrade under stress conditions, impacting overall product stability.