Accueil
Résultat de la recherche
2 résultat(s) recherche sur le tag 'acids''
Ajouter le résultat dans votre panier Affiner la recherche Générer le flux rss de la recherche
Partager le résultat de cette recherche
Exfoliation for sensitive skin with neutralized salicylic acid ? / Eve Merinville in IFSCC MAGAZINE, Vol. 11, N° 2 (04-05/2008)
[article]
Titre : Exfoliation for sensitive skin with neutralized salicylic acid ? Type de document : texte imprimé Auteurs : Eve Merinville, Auteur ; Aurelie Laloeuf ; Garrett Moran, Auteur ; Olivia Jalby, Auteur ; Anthony V. Rawlings, Auteur Année de publication : 2008 Article en page(s) : p. 115-119 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Exfoliation 'Hydroxy acids' 'Salicylic acid' 'Stratum corneum' Résumé : Hydroxy acids enjoy tremendous interest in cosmetology thanks to their skin anti-ageing and water barrier enhancing activities. One of their actions is to promote the natural stratum corneum (stratum corneum) desquamatory process. However, their use is limited due to an inherent pH-related irritancy potential which is even more exacerbated on sensitive skin. Clearly there is an opportunity for improvement. In this research we evaluated in humans the efficacy of salicylic acid, and its salts, as a corneodesmolytic agent using the dihydroxyacetone method and measuring the reduction in skin staining with treatment over time using a chromameter. Salicylic acid at 2% in a preparation of pH 3.12 significantly increased exfoliation by 10.9% compared with placebo (P < 0.05), confirming its desquamatory enhancing properties. Then the effect of vehicle cream pH on salicylic acid activity was studied. Salicylic acid at close to neutral pH (mostly in its neutralized form as salicylate, pH 6.50) exerted a corneodesmolytic activity as good as that of salicylic acid in an acidic vehicle (pH 3.12) after only two days of application. Furthermore, the performance of glycolic acid and salicylic acid salts as exfoliants were compared at pH 6.50. When these two hydroxyl acids were formulated at the same molar level in a cosmetic base (14.47mmol L-1), the salicylic acid preparation gave an 8.2% increase in stratum corneum desquamation compared with the glycolic acid preparation (P < 0.05). The corneodesmolytic effects were confirmed using a tape-stripping assay combined with a quantitative protein assay. Neutralized salicylic acid was found to enhance the removal of stratum corneum proteins significantly more than the vehicle after 25 sequential tape strippings (14%; P < 0.05). Finally, salicylic acid had no significant influence on skin water barrier properties after 22 days of treatment. In the second phase of this research we assessed the suitability of neutralized salicylic acid as an ingredient for sensitive skin. A stinging test was performed according to the Frosch & Kligman method to evaluate the influence of the formulation base-pH on stinging potential. Salicylic acid formulated at pH 6.50 induced no stinging sensation (score 0) in contrast to salicylic acid at pH 3.12 (score 19; P < 0.05). In addition, a clinical study was conducted to assess the erythema induced on volunteers’ cheeks after a single application of a neutralized salicylic acid (1%) formulation compared with placebo. Visual redness was assessed by a dermatologist and then measured with a Mexameter. No significant differences were observed. Moreover, half of the panel had sensitive skin and no correlation could be established between redness and/or abnormal sensation and sensitive skin. In conclusion, neutralized salicylic acid at a 1% concentration is a suitable exfoliant agent for subjects with sensitive skin. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10371
in IFSCC MAGAZINE > Vol. 11, N° 2 (04-05/2008) . - p. 115-119[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 010540 - Périodique Bibliothèque principale Documentaires Disponible Polymeric ester technology - an effective delivery concept for sun and skin care / D. Smith in IFSCC MAGAZINE, Vol. 3, N° 3 (07-08-09/2000)
[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 antisolairesTags : '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.
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[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 004649 - Périodique Bibliothèque principale Documentaires Disponible