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  • 1
    Digitale Medien
    Digitale Medien
    Formulation and interest of a decorative emulsifier-free O/W emulsion with a positive zeta potential (2001)
    Oxford, UK : Blackwell Science Ltd
    International journal of cosmetic science 23 (2001), S. 0 
    Details
    ISSN: 1468-2494
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Synopsis The aim of this study was to formulate an emulsifier-free foundation with a positive zeta potential. This formulation was achieved through a comparative study carried out on 16 cationic hydrogels. Measurements of the cationic activity of those gels were undertaken. Sixteen emulsions, including 0.4% of cationic gel, were formulated and the zeta potential of each was quantified. No correlation between those two measurements could be established.Pigments introduced in the emulsion to obtain a foundation slightly reduced the zeta potential value of the formula. The skin coloration induced by the application of the formula with a positive electric charge was found more stable than that of classical and transfer-proof formulae. Moreover, this formula displayed a higher hydrating potential compared to transfer-proof formulae. Résumé Le but de cette étude était de formuler un fond de teint présentant un potentiel zêta positif. Cette formulation a été mise au point à la suite d’une étude comparative menée sur 16 gels cationiques hydrophiles. Les mesures de l’activité cationique de ces gels ont été réalisées. Seize émulsions contenant chacune 0.4% de gel cationique ont été formulées et leur zêta potentiel mesuré. Aucune corrélation n’a pu être établie entre ces 2 types de mesures.Les pigments, introduits dans l’émulsion pour obtenir un fond de teint, ont faiblement diminué la valeur du potentiel zêta de la formule. La coloration de la peau, induite par l’application de la formule ayant une charge électrique positive, a étée jugée plus stable que celle de formules traditionnelles ou non transferts. Cette formulation présentait de plus, des propriétés hydratantes beaucoup plus importantes que des formules non transferts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1467-2494.2001.00052.x
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  • 2
    Digitale Medien
    Digitale Medien
    Sunscreen in vitro spectroscopy: application to UVA protection assessment and correlation with in vivo persistent pigment darkening (2002)
    Oxford, UK : Blackwell Science, Ltd
    International journal of cosmetic science 24 (2002), S. 0 
    Details
    ISSN: 1468-2494
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: In the present study, we have described an in vitro spectroscopic method to evaluate the sunscreen products for UVA sun protection factor. The roughened PMMA plates have been used as a transparent substrate on to which the test product is spread. The UVA protection factors have been deduced from the UV-transmittance data measured in the UVA area. In order to be as close as possible to the in vivo protection factors, issued from the PPD end-point, the treated polymethylmethacrylate (PMMA) plates are submitted to different UV-irradiation doses, before the measurement. The correlation in vitro/in vivo is poor when the sunscreens are not irradiated. A UV dose of about 2 minimal pigmenting dose (MPD) is enough to achieve a good correlation between in vitro and in vivo data issued from the 13 tested sunscreens. These results are consistent with the fact that the photostability of sunscreens is challenged during an in vivo PPD test.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1467-2494.2002.00130.x
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  • 3
    Digitale Medien
    Digitale Medien
    O/W emulsion and W/O/W multiple emulsion: physical characterization and skin pharmacokinetic comparison in the delivery process of caffeine (1998)
    Dordrecht, The Netherlands : Kluwer Academic Publishers
    International journal of cosmetic science 20 (1998), S. 0 
    Details
    ISSN: 1468-2494
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The aim of this study was to compare the characteristics of an O/W emulsion and a W/O/W emulsion, formulated with similar ingredients. The physical properties of these two types of vehicles were characterized first. Using three types of in vitro models, human skin biopsies, nitrate acetate cellulose membranes and human reconstituted epidermis, the delivery potential of each vehicle for one hydrophilic drug, caffeine, was compared. The assessment of physical parameters, such as particle size, conductivity and rheological behavior enabled the nature of the test emulsions to be clearly identified. Clear differences were observed in the ability of each type of emulsion to deliver caffeine. Whatever the nature of the membrane used for the pharmacokinetic study, the absorption of caffeine was roughly two-fold lower (2.6 for human skin) when the W/O/W multiple emulsion was used as the vehicle. The concomitant determination of physical and kinetic properties of these two test emulsions allowed the W/O/W multiple emulsion and a simple O/W emulsion to be clearly differentiated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1467-2494.1998.181621.x
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  • 4
    Digitale Medien
    Digitale Medien
    The effectiveness of molecular oxygen in cosmetic formulations (1996)
    Oxford, UK : Blackwell Publishing Ltd
    International journal of cosmetic science 18 (1996), S. 0 
    Details
    ISSN: 1468-2494
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: In a preliminary clinical study, two cosmetic preparations were compared, one without an oxygen carrier and therefore without oxygen, the other one containing the oxygen carrier, fully saturated with oxygen. The parameters measured were the moisture content of the skin and the skin profile. Since the oxygen-free product contained the same ingredients, including phospholipids in liposomal form, with the exception of perfluorodecalin – the oxygen carrier, this investigation showed that perfluorodecalin plus molecular oxygen improves the barrier function of the skin. In a second clinical study, five cosmetic preparations containing various amounts of molecular oxygen from 1.44 ml to 4.5 ml per 100 ml product were compared. The parameters measured were the oxygen partial pressure of the skin, the moisture content of the skin, and the skin profile. A linear dose-dependent increase in oxygen partial pressure of the skin (r=0.978) and a linear dose-dependent reduction in fine lines and wrinkles (r=0.9855) was found. The results for the increase in skin moisture were more difficult to interpret. There seemed to be an overlap of the moisturizing base with the efficacy coming from the increasing amount of oxygen per application.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1467-2494.1996.tb00143.x
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  • 5
    Digitale Medien
    Digitale Medien
    Photochemical behavior assessment of sunscreen preparations by in vitro UV spectroscopy (2004)
    Oxford, UK : Blackwell Science Ltd
    International journal of cosmetic science 26 (2004), S. 0 
    Details
    ISSN: 1468-2494
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: In this study, we used a spectroscopic method, found effective in measuring sunscreen photo-degradation results in terms of a photoabsorption decrease. The traditional approach was to measure variations in well-known parameters such as the absolute in vitro sun protection factor (SPF) or the relative UVA/UVB ratio after a controlled dose of UV radiation. However, these parameters fail to fully reflect the product's photochemical behavior. Variation in the SPF mainly depicts changes in UVB filtration, and variation in the relative parameter UVA/UVB ratio can be subjected to misinterpretation, as is the case for products in which a parallel loss of photoabsorption is observed in the UVA and UVB regions. In our laboratory, we developed a new approach using pure spectroscopic UVA and UVB attenuation factors called UVA attenuation factor and UVB attenuation factor. Attenuation factors are defined here as the inverse of the arithmetic mean of the transmittance data, taken either from the UVB region (290–320 nm, 1 nm steps) or the UVA region (320–400 nm, 1 nm steps). Using these two new spectroscopic indices, the photochemical behavior of a sunscreen formula can be assessed in each UV region. The general procedure consists of applying two UV doses to a film of sunscreen previously spread on a roughened polymethylmethacrylate plate and then measuring the UV transmission versus wavelength before and after the irradiation process. We tested different UV filters in a cosmetic base to demonstrate the efficacy of the method.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1467-2494.2004.00244_3.x
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  • 6
    Digitale Medien
    Digitale Medien
    Characterization of the barrier function in a reconstituted human epidermis cultivated in chemically defined medium (2002)
    Oxford, UK : Blackwell Science, Ltd
    International journal of cosmetic science 24 (2002), S. 0 
    Details
    ISSN: 1468-2494
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The aim of the study was to characterize and assess the maturation process of the barrier function in a reconstituted human epidermis (REp) cultivated in a chemically defined medium. For this purpose histo-morphological analysis, percutaneous absorption studies and non-invasive measurements were performed. In order to understand the time course of the barrier development, REp cultivated from the same pool of normal human keratinocytes were harvested and measured after several increasing periods of exposure at the air–liquid interface. From these results we concluded that a maturation period of at least 16 days at the air–liquid interface was required for an optimal barrier function development of REp. At this time point, the permeability of the skin cultures for caffeine (CAF) was 20–25-fold higher than that of normal human skin (NHS) biopsies. Non-invasive measurements of skin water content, transepidermal water loss (TEWL) and pH were achieved after the same period of time. Results showed that the stratum corneum (SC) of REp was slightly more hydrated than that of ex vivo and in vivo, human skin. TEWL was slightly higher through REp than through NHS, and the pH of the REp models was very close to that of in vivo, normal human skin. In the latter part, assuming that this type of model could be routinely used, we quantified over a 1-year period the barrier function variability of this skin culture model between batches. The satisfactory results obtained with a 20% coefficient of variation indicated that this REp model has a consistent and reproducible barrier function. This leads us to suggest that the skin model might be considered an alternative membrane to normal human skin for permeation screening tests.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.0412-5463.2001.00112.x
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  • 7
    Digitale Medien
    Digitale Medien
    Crystal Clear Transparent Lipstick Formulation Based on Solidified Oils (1999)
    Dordrecht, The Netherlands : Blackwell Science Ltd
    International journal of cosmetic science 21 (1999), S. 0 
    Details
    ISSN: 1468-2494
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: We have developed a lipstick, the stick of which looks totally transparent.The base, coloured or not, may contain high concentration of actives or fragrances.The present study examines the process of determination of oils and solidifying agents.The selecting criterion include visible spectroscopic measurements to quantify transparency of the formulated product. We have also validated the stick hardness through drop point and breakage measurements.After several investigations, we selected a mixture of oils and solidifying agents.The oil network obtained has been characterized through optical microscopy, transmission electronic microscopy, X-ray diffraction and differential scanning calorimetry. We can show that the final product we obtained is amorphous and its solidity can be explained by chemical bonds formation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1467-2494.1999.211909.x
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  • 8
    Digitale Medien
    Digitale Medien
    Investigations on surface diffusion in sparingly soluble monolayers at the gas/liquid interface using radiotracer technique (1980)
    Springer
    Colloid & polymer science 258 (1980), S. 1176-1182 
    Details
    ISSN: 1435-1536
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Zur Schaffung günstiger Bedingungen für den experimentellen Nachweis von Oberflächendiffusionsvorgängen in schwerlöslichen Monoschichten an der Phasengrenze Gas/Flüssigkeit mit Hilfe der Radiotracertechnik wurden mögliche Einfluggrößen, wie Verdampfung, Desorption und Konvektion, untersucht. Aus Radiotracermessungen resultierte, dag der Anteil von Verdampfung und Desorption bei langkettigenn-Alkanolen undn-Alkansäuren vernachlässigt werden kann. Auch bei einwandfreier Versuchsdurchführung traten langzeitige Bewegungen des Monoschichtmaterials auf, die einmal zur lateralen Verschiebung der Grenze markiert/nichtmarkiert, zum anderen zur „wellenförmigen” Umverteilung des anfangs statistisch homogen verteilten Monoschichtmaterials führten. Die Analyse möglicher mechanischer und thermischer Ursachen ergab, daß diese Erscheinungen nur durch temperaturbedingte Dichteinstabilität in der Volumenphase des Troges erklärt werden können. Auf dieser Basis wird ein Modell vorgeschlagen, das die Ausbildung komprimierter und expandierter Bereiche des Monoschichtmaterials erklärt.
    Notizen: Summary For creating favourable conditions for the experimental proof of surface-diffusion processes in sparingly soluble monolayers at the gas/liquid interface by means of radiotracer technique, possible factors of influence such as evaporation, desorption and convection were studied. From radiotracer measurements it followed that the share of evaporation and desorption in case of long-chained n-alkanols and n-alkane-carboxylic acids can be neglected. Even at correct experimental setup long-term movements of monolayer material occurred which, on the one hand, induced a lateral shifting of the boundary labelled/non-labelled, on the other a “wavelike” distribution of the monolayer material which initially had a statistically homogeneous distribution. The analysis of possible mechanical and thermal causes showed that these phenomena can be explained only by temperature-induced density instability in the volume phase of the trough. On this basis a model is proposed which explains the formation of compressed and expanded areas of monolayer material.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01382463
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  • 9
    Digitale Medien
    Digitale Medien
    Investigations on surface diffusion in sparingly soluble monolayers at the gas/liquid interface using radiotracer technique (1980)
    Springer
    Colloid & polymer science 258 (1980), S. 1289-1295 
    Details
    ISSN: 1435-1536
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Ein Verfahren zur Berechnung der Oberflächenselbstdiffusionskoeffizienten in schwerlöslichere Monoschichten an fluiden Phasengrenzen auf der Grundlage von Radiotracermessungen und unter Berücksichtigung der Zählrohrgeometrie wird vorgeschlagen. Auf dieser Basis ist eine Auswertung der Experimentalergebnisse möglich, ohne daß zur Oberflächenselbstdiffusion in Konkurrenz stehende Transportvorgänge berücksichtigt werden müssen. Untersucht wurden Monoschichten verschiedener längerkettigern-Alkanole undn-Alkancarbonsäuren im Flächenbereich zwischen 0,23 nm2/Molekül und 2 nm2/Molekül. OberflächenselbstdiffusionskoeffizientenD s wurden nur bis zu Flächenwerten von 0,75 nm2/Molekül bestimmt, weil bei höheren Flächen die Auswertung der Oberflächenkonzentrationsänderungen wegen des zunehmenden Einflusses von Dichtekonvektion ungenau wird. DieD s -Werte liegen für die untersuchten Systeme in der Größenordnung 10−5 cm2/s. Bei allen untersuchten Verbindungen nehmen die Werte von Ds mit steigender Fläche pro Molekül zu. Außerdem wurde die Abhängigkeit von der Art der hydrophilen Gruppe und der Alkylkettenlänge der Monoschichtmoleküle nachgewiesen. Die Ergebnisse wurden anhand verschiedener Modellvorstellungen diskutiert.
    Notizen: Summary A method is proposed for calculating surface selfdiffusion coefficients in sparingly soluble monolayers at fluid interfaces based on radiotracer measurements and allowing for counter geometry. On this basis an analysis of experimental results is possible without having to allow for processes competing with surface self-diffusion. Monolayers of various long-chainn-alcohols andn-alkane-carboxylic acids were studied in the area range between 0.23 nm2/molecule and 2.0 nm2/molecule. Surface self-diffusion coefficientsD s were determinded only up to areas of 0.75 nm2/molecule since, in case of greater areas, the analysis of surface concentration becomes inexact due to the increasing influence of density convection. For the systems studied,D s values lie in the order of 10−5 cm2/s. In all compounds studied, the values ofD s increase with area per molecule. In addition, dependence on the type of hydrophilic group and alkyl-chain length of monolayer molecules was proved. The results are discussed by means of various model concepts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01668775
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  • 10
    Digitale Medien
    Digitale Medien
    Characterization of the interaction between gelatin and a spread monolayer of octadecanoic acid (1985)
    Springer
    Colloid & polymer science 263 (1985), S. 778-781 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Gelatin ; ionic surfactants ; adsorption ; surface rheology ; octadecanoic acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Surface rheological measurements of octandecanoic acid monolayers spread on gelatin solutions were performed. The interaction of the spread monolayer with the gelatin involves a strong rise of the solidity of the surface structure with distinct viscoelastic properties and is comparable with the experimental findings looking into the interaction between gelatin and an ionic surfactant. The results found by the addition of sodium-dodecylsulfate to the gelatin solution are discussed, assuming the formation of a multilayer consisting of octadecanoic acid molecules interacting to a negligible degree with the gelatin-surfactant complexes displaced from the surface. The surface rheological parameters are influenced by both layers in opposition to the dynamic behaviour at compression and dilation described in the first part of this paper. An analogous effect is found if the cationic hexadecyltrimethylammoniurn-bromide is added to the gelatin solution. The influence of CTAB is interpreted as the consequence of a steric hindrance, caused by the concentration of groups with opposite charges on the small polar ranges of the gelatin molecules. As a particular interaction of octadecanoic acid with the complexes is possible, a mixed adsorption layer is formed and the high solidity of the surface layer is prevented by the presence of molecules not interacting with the complexes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01422862
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