[article]
| Titre : |
Polymeric ester technology - an effective delivery concept for sun and skin care |
| Type de document : |
texte imprimé |
| Auteurs : |
D. Smith, Auteur ; A. O'Connor, Auteur ; D. Young, Auteur ; R. Siegfried, Auteur |
| Année de publication : |
2000 |
| Article en page(s) : |
p. 21-30 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Cosmétiques
Polyesters
Produits antisolaires
|
| Tags : |
'Alpha hydroxy acids' Desquamation 'Gas chromatography' Sunscreens 'Topical delivery system' Dihydroxyacetone 'Skin whiteners' Hydroquinone 'Lactic acid' |
| Index. décimale : |
668.5 Parfums et cosmétiques |
| Résumé : |
Several years ago we discovered that polyesters mitigate skin penetration of organic UV absorbers. Our initial research explored the effect of polyester structure on its’ ability to focus and maintain organic UV absorbers in the outer stratum corneum (SC) of skin. Delivery technologies that can mitigate skin penetration of UV absorbers, as polyester technology has been proven to do, are of interest to formulators and marketers of sunscreens. Current market trends favor products with SPF ratings above 15 and the inclusion of UV absorbers in “daily-wear” products, increasing both the level and duration of exposure to UV absorbers. Clinical studies that the Personal Care Application Group had commissioned with sunscreen actives, indicated that polyesters facilitate retention of up to 95% of applied organic UV absorbers in-vivo. Polyesters have also been shown to increase the solubility of oxybenzone, improve coupling of actives, and enhance SPF efficiency and effectiveness. Through our research, we were able to gain a better understanding of the relationship between polyester structure and skin penetration. With this knowledge, we gained ability to design and synthesize polyesters into which specific polarity actives could partition.
The next phase of our research focused on screening and optimizing polyesters to maximize benefits derived from the application of water-soluble active ingredients, such as alpha hydroxy acids. Hydroxy acids are generally thought to improve the appearance of skin via reduction in corneocyte adhesion leading to accelerated exfoliation and an increase rate of SC cell renewal. Effectiveness of hydroxyl acids could be maximized if distributed and maintained throughout the entire SC. By maintaining hydroxyl acids in the SC, contact with viable cells in the dermis is minimized, thereby reducing their potential for sensory stinging and irritation. We found that with the incorporation of polyesters, a reduced level of AHA can be utilized with efficacy of the hydroxyl acid maintained, thereby lowering the irritation potential attributed by the hydroxy acid.
For the AHA research, a series of polyesters with varied structural characteristics were formulated in emulsions containing the hydroxy acid, lactic acid. The effect of these formulations on human skin was examined in-vivo using a comparative cytology method determining the change in squamous cell size at weekly intervals over twenty-eight days. Results indicate specific polyesters are useful in optimizing and sustaining delivery of lactic acid. Preliminary panels studies suggest that polyesters also reduce the potential for lactic acid to sting and cause irritation.
Other hydrophilic actives were our polyester technology. A preliminary investigation was also conducted on the ability of polyesters to enhance delivery to dihydroxyacetone ( DHA), which is the most widely used sunless tanning ingredient. These experiments suggest that the color persistence and color intensity attributed to DHA is enhanced when used in combination with specific, select polyesters. Hydrophilic skin whitening activities are a popular market trend, and were also investigated with our polyester technology. The two skin whitening actives utilized for our studies were hydroquinone and lactic acid. Lactic acid has been found to elicit a skin whitening response. Clinical in-vivo panel tests were conducted to access the ability of the polyesters to enhance the performance attributed by these skin-whitening agents.
Based on the results of the AHA, DHA, and skin whitening experiments, coupled with the ability to synthesize polyesters with regard to an active ingredient’s solubility parameters, polyesters have proven to be effective controlled delivery systems for hydrophilic as well as lipophilic actives.
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| Note de contenu : |
- EXPERIMENTAL - MATERIALS AND METHODS : Evaluation of lipophilic sunscreen actives with polyesters - Evaluation of hydrophilic actives with polyesters - Formulas used in comparative cytology method for AHA performance criteria - Conduct of panel for comparative cytology study - Test formulations used in dihydroxyacetone (DHA) study - Skin whitening test formulations - Hydroquinone test formulation - Lactic acid skin whitening formulation - Conduct of hydroquinone skin whitening study.
- RESULTS : Polyesters with lipophilic organic sunscreen actives - Polyesters with hydrophilic actives - Skin whitening study with hydroquinone - Skin lightening with lactic acid. |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10806 |
in IFSCC MAGAZINE > Vol. 3, N° 3 (07-08-09/2000) . - p. 21-30
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