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International audience; Container-content interactions are common in the food and pharmaceutical industries. However, these studies are more complicated in the cosmetic industry, and it is necessary to ensure consumer safety. The objective of this work was to develop a strategy for the toxicological evaluation of leachables for cosmetic packagings. Eleven common plastic packagings were selected to evaluate interactions with 5 simulants (acidic, alkaline and neutral water, 30% and 96% ethanol) chosen to mimic cosmetics behavior. A GC-MS method was developed to screen for 12 non-intentionally added substances of particular concern: 10 phthalates, bisphenol A and distearyl thiodipropionate (European Pharmacopoeia plastic additive 17). Results were analyzed using a toxicological procedure established for this study. Some phthalates and bisphenol A were detected in several samples, but only one contaminant, diisobutyl phthalate (DiBP), was found to be above the set concentration threshold. Using toxicological data, this concentration was found to be safe for users. 96% ethanol appeared to be the strongest simulant in term of extraction, with a maximum concentration of 491 μg/L for DiBP in a 100% styrene-acrylonitrile copolymer packaging. In water simulants, less contaminants were extracted, with concentrations under 20 μg/L.

International audience; Abstract Background/purpose: The purpose of this clinical study was to identify dielectric markers to complete a previous thermal and vibrational study on the molecular and organizational changes in human dermis during intrinsic and extrinsic aging. Methods: Sun-exposed and non-exposed skin biopsies were collected from 28 women devised in two groups (20-30 and ≥60 years old). The dielectric relaxation modes associated with localized and delocalized dynamics in the fresh and dehydrated state were determined by the Thermostimulated currents technique (TSC). Results: Intrinsic and extrinsic aging induced significant evolution of some of the dielectric parameters of localized and delocalized dynamics of human skin. With photo-aging, freezable water forms a segregated phase in dermis and its dynamics is close to free water, what evidences the major role of extrinsic aging on water organization in human skin. Moreover, TSC indicators highlight the restriction of localized mobility with intrinsic aging due to glycation, and the cumulative effect of chronological aging and photo-exposition on the molecular mobility of the main structural proteins of the dermis at the mesoscopic scale. Conclusion: TSC is a well-suited technique to scan the molecular mobility of human skin. It can be uses as a relevant complement of vibrational and thermal characterization to follow human skin modifications with intrinsic and extrinsic aging.

Potentiometry and cyclic voltammetry were proposed as simple, reliable and non invasive methods for the simultaneous determination of pH and antioxidant properties of skin. Experiments were performed with microelectrodes just deposited on skin surface without any gel or water added. pH was measured by means of the zero current potential of a tungsten W/WO3 sensor. A nerstian response was recorded in pH range 4 to 6 corresponding to the normal skin pH values. The global antioxidant capacity was deduced from the anodic charge passed during the plotting of cyclic voltammograms on platinum or gold microelectrodes. Comparing the half wave or peak potentials of these curves with those recorded for experiments performed in aqueous solution, the main hydrophilic antioxidants species were detected, i.e. ascorbic acid, uric acid and glutathione. This relatively easy-to-use analytical method made it possible to follow in real time the efficiency of topic treatment as well as to study the influence of oxidative stress.

In this work, a study about solute continuous extraction from vegetable matrix is undertaken. An industrial apparatus is used and the problems are to identify information to be acquired in order to process implementation. To this end, a batch study was carried out to obtain the extraction kinetics, as well as a study of the matter behaviour under pressure and a study of raw plant transport. Finally, to couple these elements makes it possible to represent the extraction yields according to time in the apparatus. A methodology for the change from batch to continuous extractor based on laboratory tests is proposed.

BackgroundRecent works present evidence of Propionibacterium acnes growing as a biofilm in cutaneous follicles. This formation of clusters is now considered as an explanation for the in vivo resistance of P. acnes to the main antimicrobials prescribed in acne vulgaris.PurposeOur objective was to explore this hypothesis and propose a new therapeutic approach focusing on anti-biofilm activity of Myrtacine® New Generation (Mediterranean Myrtle extract–Botanical Expertise P. Fabre) alone or combined with antibiotics.Methods/ResultsUsing in vitro models able to promote the growth of adhered bacteria, the loss of sensitivity of P. acnes biofilms (48 h) towards erythromycin and clindamycin was checked considering either sensitive or resistant strains. In the same time, the activity of Myrtacine® New Generation against biofilm formation and mature biofilm (48 h) was evaluated. Using a dynamic model of biofilm formation, we noted an inhibition of biofilm formation (addition of Myrtacine® New Generation at T 0) and a significant effect on mature biofilm (48 h) for 5 min of contact. This effect was also checked using the static model of biofilm formation for Myrtacine® New Generation concentrations ranging from 0.03% to 0.0001%. A significant, dose-dependent anti-biofilm effect was observed and notable even at a concentration lower than the active concentration on planktonic cells, i.e. 0.001%. Finally, the interest of the combination of Myrtacine® New Generation with antibiotics was explored. An enhanced efficacy was noted when erythromycin (1000 mg/l) or clindamycin (500 mg/l) was added to 0.001% Myrtacine®, leading to significant differences in comparison to each compound used alone.ConclusionThe efficiency of Myrtacine® New Generation on P. acnes biofilm alone or combined with antibiotics was demonstrated and can lead to consider it as a potent adjunctive product efficient during the antibiotic course for acne vulgaris treatment.

Cyclic voltammetry is proposed as a new method for evaluating the antioxidant capacity of skin based on the reducing properties of low molecular weight antioxidants (LMWA). Experiments were performed simply by recording the anodic current at 0.9 V/SCE of a platinum microelectrode placed directly on the epidermis surface without any gel or water. This method ensured a direct, rapid (less than 1 min), reliable (accuracy 12%) and non-invasive measurement of the global antioxidant capacity of the stratum corneum with a high spatiotemporal resolution. At the same time, the pH of the skin surface was determined by recording the cathodic current at 0 V/SCE. Based on an exploratory study involving nine volunteer subjects, the evolution of the amperometric response of the microelectrode with time revealed a periodic modification of the redox properties.