摘要:

SynopsisUne recherche bibliographique des données de la littérature médicale fait le point sur le métabolisme et le rôle possible de l'acide pyrrolidone carboxylique (PCA) et de son sel de sodium (PCNa) dans la peau, particulièrement au niveau du Stratum Corneum. L'article présente également une série d'évaluations biophysiques (impédance et relaxation α) et cliniques des propriétés hydratantes des crèmes ou lotions contenant l'acide et/ou son sel.II est maintenant acquis que le couple PCA/PCNa est un agent hydratant efficace et que toutes les préparations cosmétiques qui en contiennent au moins 2% ont un effet bénéfique sur les peaux sèches à condition que le véhicule utilisé pénètre dans les couches superficielles du Stratum Corneum (les solutions aqueuses ne conviennent pas).Pyrrolidone carboxylic acid and the skinSummaryThe medical and biological literature was reviewed with stress laid on the role of pyrrolidone carboxylic acid (PCA) and its sodium salt (NaPCA) in skin, its metabolism, its functions.The paper also includes a summary of 8 years of evaluation work carried out in our Laboratory on creams and lotions containing PCA‐NaPCA which were assessed by biophysical (impedance measurement, α relaxation) and clinical methods.It is now definitely demonstrated that PCA is an hydrating agent and that all the cosmetic preparations containing at least 2% of the PCA‐NaPCA salt system improve the condition of dry skin at short or long term provided an adequate vehicle is used (e.g. aqueous solutions are ineffective).The mecanism of action is discussed with reference to metabolism and physiological r

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1981.tb00275.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SynopsisParmi les avertissements apparus nécessaires à la protection de l'utilisateur et devant figurer sur les récipients, emballages ou notices des produits cosmétiques et d'hygiène corporelle, il en est un concernant la lanoline. La réglementation prévoit l'inscription de la mention ‘important contient de la lanoline'. Des réactions cutanées de type allergique ont été rencontrées ces dernières années apèes application de produits contenant de la lanoline ou des dérivés de lanoline, alors que la lanoline est utilisée depuis très longtemps.Ces pourquoi les auteurs ont voulu vérifier expérimentalement chez le Cobaye l'hypersensibilité cutanée à la lanoline et à ses dérivés, et notamment aux alcools gras de lanoline qui sont incriminés par de nombreux auteurs.Aucune réaction n'a été observée avec une lanoline purifiée, même si celle‐ci est ancienne.Une faible potentialité d'allergénicité a été mise en évidence avec un dérivé semiliquide. Des réactions de sensibilisation ont été observées avec un échantillon d'alcools gras de lanoline.Ces résultats sont analysés et comparés à ceux publiés dans la littérature.Cutaneous hypersensitivity tests in guinea‐pig of lanolin and derivatives used in cosmetologySummaryAmong the warnings which are now necessary in Europe for the protection of the consumer and which must appear on the packagings of cosmetic and corporal hygiene products, there is one concerning lanolin. The regulation requires the mention ‘Important, this product contains lanolin'. Cutaneous allergic reactions have been reported in the last few years after application of products containing lanolin or lanolin derivatives although lanolin has been used for a long time.The paper describes tests of cutaneous hypersensitivity on the guinea‐pig with lanolin, lanolin alcohol and a semi‐liquid lanolin.No reaction was observed with a purified lanolin, even if it was old.A weak allergenic effect was shown with the semi‐liquid derivative. Sensitization reactions were observed with a sample of lanolin fatty alcohols.These r

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1981.tb00276.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SynopsisL'influence du pH et de la lumière sur la stabilité intrinsèque de quelques antioxydants naturels et synthétiques a étéétudiée en milieu hydroalcoolique.Des différences importantes de stabilité ont été observées selon le pH du milieu et la présence ou l'absence de lumière. Des mesures ont été effectuées également dans des émulsions H/E contenant un antioxydant. II découle de cette étude que lors du choix d'un antioxydant pour protéger un milieu donné, on doit vérifier au préalable que le pH du milieu et la présence éventuelle de lumière n'affectent pas sa stabilité intrinsèque. Les antioxydants ont été mesurés par voltamétrie anodique.Influence of pH and light on the stability of some antioxidantsSummaryMany organic molecules can be oxidized in the presence of oxygen. Light and traces of heavy metal ions catalyse the process of oxidation. The addition of a very small quantity of antioxidant to alcoholic perfumes and cosmetic bases is often made to retard auto‐oxidations. Among the parameters which could influence the efficiency of an antioxidant, its intrinsic stability should be considered in the medium to be protected. This stability might conceivably be influenced by the pH, the presence of light, heavy metal ions and microorganisms. In this study we have concentrated on the role played by the first two factors. To eliminate a possible interference by the last two, analytical grades reagents together with chelators and high proof (80% v/v) hydroalcoholic solutions have been used. The antioxidants tested were: BHT, BHA, ethyl gallate, 2, carboxy‐6, hydroxy, 2, 5, 7, 8, tetramethyl chroman (Trolox CR) and D–L‐alpha‐tocopherol.Solutions of 0.5 mmol/kg of each antioxidant were prepared in 80% v/v hydroalcoholic solutions and the pH adjusted with citric acid and potassium hydroxyde or hydrochloric acid. The pH extended from 2.5 to 10 and thus largely covers the pH range of cosmetic products. Of each solution, 100ml were kept in hermetically closed 125ml white glass bottles stored at room temperature (22 ± 2° C) and kept in the dark or exposed to the diffuse daylight of the laboratory. The antioxidants concentrations were determined by linear sweep voltametry on gold or glassy carbon electrodes. Significant differences in behaviour were observed. BHA and BHT are stable regardless of light and pH except at high pH (≤9).Ethyl gallate vanishes rapidly in alkaline, neutral and even weakly acid pH independently of the presence of light. Trolox C and D–L‐alpha‐tocopherol demonstrated a mark

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1981.tb00277.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SynopsisBenzylidene camphor derivatives have been currently used as ultraviolet filters in sunscreen compositions. When solutions of these compounds are exposed to the light from a solar simulator, a photoinduced cis‐trans isomerization is observed. The initial quantum yields of this photochemical isomerization of studied molecules have been determined in several solvents. Their photochemical behaviour depends neither on the concentration nor on the presence or absence of oxygen or other inhibitors such as isopropanol or biacetyl. It means that the lifetime of the precursor states of isomerization is about 10−12s, that is to say, too short for them to react with neighbouring molecules.For each compound, the ratio of the respective concentrations of ‘E’ and ‘Z’ forms was also determined by photostationary state. A good agreement between theoretical and experimental values of this ratio shows that the studied compounds are only very slightly photodegradable. This was confirmed by the low values of photodegradation quantum yields.In case of the studied compounds, the isomerization process observed is totally reversible. During irradiation a photostationary state is quickly reached, each isomer may change into the other form after absorption of a photon which leads to a mixture of isomers. In practice, it is this mixture of E and Z forms which acts as UV filters.It may be said that a very short lifetime of the excited states, a good light stability and a reaction inertia under light irradiation make these compounds excellent sunscreen agents.Comportement photochimique des antisolaires. Benzylidène camphre et certans d

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1981.tb00278.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY