The skin activation and penetration capability of vitamin E acetate as an ingredient in a basic o/w cream (lamellar type), in liposomes (Rovisome) and microparticles (Roviparts), was investigated under in vitro conditions (BUS model) by the adhesive stripping method. The aim of the study was to compare the analytical results obtained by UV spectroscopy (transmission) and the conventional HPLC method. For the quantitative spectrometric assay, a classical least-squares evaluation of the spectra between 265 and 350 nm, based on the constituent spectra, was used. UV spectroscopy is an economic analytical method for evaluating a large population of samples of the horny layer taken by the adhesive tape stripping method, which is an established tool for depth profiling of substances within the stratum corneum. With regard to the irritation test, no cytotoxicity was recorded for all formulations tested. However, the Roviparts and Rovisome cream formulations induced a considerable activation of the epidermal cells that may contribute to the penetration efficiency of Rovisome-formulated vitamin E acetate. The Rovisome-formulated cream delivered a maximum amount of vitamin E acetate into the horny layer compared to the other formulations tested. The difference can be explained by an alteration of the plasticity of the horny layer inducing a strong reservoir capacity and an activation of upper epidermal cells. Moreover, the opening of the potential pathway for a follicular penetration may be part of the increased reservoir capacity.

Mainly among children incidental ingestion of conventional lamp oils (paraffin oil) is responsible for casual intoxications with severe pulmonary toxicity and fatal consequences. On the basis of the isolated blood-free perfused rat lung we developed a model to study the acute toxic effects of lamp oil. Three oils were studied: conventional paraffin lamp oil (kinematic viscosity 1.62 10(-6) m(2)/sec), the methyl ester Edenor ME C12 70 (2.7 10(-6) m(2)/s) and another ester Edenor LPL (4.5 10(-6) m(2)/s). The oils were instilled into the trachea of isolated rat lungs and the changes in lung mechanics (tidal volume, pulmonary compliance and pulmonary conductance) as well as edema formation (increase in lung weight) studied. Instillation of as little as 10 microl paraffin oil caused complete failure of lung functions within 20 min and even 2 microl caused noticeable edema. Similar results were obtained with Edenor ME C12 70, which appeared to be even more toxic than paraffin oil, while Edenor LPL was less toxic. We conclude that tracheal instillation of oils into isolated perfused rat lungs may be a useful model to study the toxicity of lamp oils in vitro. Our findings further suggest that Edenor LPL may be a safer alternative for use as a lamp oil than paraffin oil.

Dermatology studies focussing on the stratum corneum were carried out by infrared attenuated total reflection (ATR) spectroscopy using flexible fibre-optic probes made from square cross-section polycrystalline silver halide material. We compared the upper horny layer of human and bovine udder skin (BUS). As a substitute for human in vivo tests, the in vitro model of the isolated perfused bovine udder skin (BUS-model) has been used. For depth profiling of endogenous and topically applied compounds, subsequent stripping of corneocyte layers by adhesive tape application was carried out in combination with in situ fibre-probe ATR-measurements. The non-invasive measurement technique was also applied to patients with various skin abnormalities. Owing to the remote sensing capability, the technique presented is promising, since it opens the field for new medical and cosmetic applications, which are otherwise not possible with conventional sampling compartment based ATR-accessories.

The potential of mid-infrared attenuated total-reflection spectroscopy for dermatology studies has been increased by the development of a flexible fiber-optic probe from silver halide material. Such a tool significantly eases epidermal surface characterization. Spectra of human forearm skin and of bovine udder skin (BUS-model), which is used as a substitute for in-vivo tests on man, were compared, and as an example low concentrations of vitamin E acetate (α-tocopherol acetate) in the stratum corneum were measured after topical skin application. Depth profiling was enabled by repeated steps of tape stripping and subsequent skin measurement. The infrared methodology is rapid and can be applied to small areas of skin. It is also sufficiently sensitive for analysis of a large variety of cosmetic formulations and dermatopharmaca. Discrimination of vehicle formulations is possible because of the large information content of mid-infrared spectra.

2-Ethylhexyl stearate was investigated in an embryo-/foetotoxicity and teratogenicity study on rats according to OECD guidelines for the testing of chemicals (No. 414). Dose levels of 0 (arachidis oil), 100, 300 and 1000mg/kg body weight/day were administered by gavage. Dams tolerated the applied dose levels without any toxic effects. Pre- and post-implantation loss and mean numbers of resorptions were unaffected by treatment. All parameters were comparable with the animals of the control group. Skeletal and visceral investigations revealed no treatment-related malformations. For embryo-/foetotoxicity, teratogenicity and maternal toxicity a NOAEL of 1000mg/kg was deduced.

Bioactives are a major focus of the recent developments in cosmetics. Most of these ingredients will work only if they penetrate the stratum corneum and reach the living epidermis. The extent and race of penetration of bioactive ingredients from cosmetic products is of paramount interest. A systematic in vitro study of penetration into stratum corneum and viable skin was performed using the isolated perfused bovine udder skin (BUS) model.As bioactive ingredients, oil-soluble vitamin E, vitamin E acetate, and water-soluble D-panthenol were incorporated into different cream formulations and a shower gel. Under leave-on conditions (exposure periods of one hour and five hours), the changes in phase behavior and viscosity have a strong impact on the penetration pattern. Generally, the water-soluble D-panthenol penetrates faster and in a higher amount into the stratum corneum than the oil-soluble vitamin E, Regarding the choice of the galenic vehicles, the penetration of both the oil-soluble and water-soluble Vitamin is faster and much higher from w/o-cream than from lamellar o/w-cream due to changes in phase behavior. In contrast to the lamellar o/w-emulsion, for the w/o-emulsion there is no difference in the penetration of vitamin E between one hour and five hours (e.g., a steady state is already reached after an exposure period of 1 h). The top ten skin layers (200 mu m depth) again reflect the influence of the emulsion formulation on the vitamin E absorption. From the w/o-cream the penetration is faster and more efficient than from the lamellar o/w-cream.Under rinse-off conditions (3*2 minutes), the water-soluble D-panthenol penetrates in a higher amount than the oil-soluble vitamin. However, the penetration effect is detectable even after the extremely short period of exposure. Due to the fact that the shower gel will nor change the phase behavior, different routes of penetration may be considered for water- and oil-soluble vitamins.

Bedingt durch die 6. Änderung der EG-Kosmetik-Richtlinie sind Konzepte gefordert, die dem höheren Qualitäts- und Sicherheitsniveau der Erzeugnisse und ihrer Inhaltsstoffe sowie dem Schutz der Versuchstiere gleichermaßen Rechnung tragen. Neben dem Nachweis der Hautver-träglichkeit gewinnen daher Fragen der Hautpenetration und -resorption vorrangige Bedeutung. Das „isoliert perfundierten Rindereuter“ (= Bovine Udder Skin - BUS Modell) erfüllt als umfaßende in vitro-Methode (Kietzmann M. et al., 1993) die Voraussetzungen für die Bearbeitung von Fragen zur Hautirritation und -penetration/-resorption. Das Modell macht es quasi unter in vivo-Bedingungen möglich, die Penetrationskinetik von Inhaltsstoffen oder Erzeugnissen in der gesamten Haut zu verfolgen und auf einer im Genotypus identischen Applikationsfläche direkt zu vergleichen. Im einzelnen sind es die Penetration in die Haut durch die Hornschichten des stratum corneum (Tesa®-Filmabrißmethode), das Eindringen in die Ober- und Unterhaut (Methode der Dermatomschnitte) oder die mögliche aber bei kosmetischen Mitteln nicht erwünschte Aufnahme in den Kreislauf des Organismus (Untersuchung des Perfusats/Lymphknotens). Studien zur möglichen Hautirritation (Firm Chamber®), in denen die Induktion zellulärer Mediatorsubstanzen (Prostaglandin E2-Spiegel) sowie die Zytotoxizität (MTT-Test) biochemisch erfaßt werden, lassen den neuen Typus eines innovativen in vitro-Hautmodells mit hoher Vorhersagekraft entstehen. Verschiedenartige Probenentnahmen, histologische Methoden und moderne Analysentechnik vervollständigen die universelle Einsetzbarkeit des Modells in Hautforschung und toxikologischer Absicherung. Beispielhaft für kosmetische Stoffe wurden Ergebnisse mit Vitamin A-palmitat, RRR-alpha Tocopherol, Cetearyl alcohol, Sodium lauryl sulfate, Alkyl polyglycoside und Ocenole (Handelsname) aufgezeigt.

The fungus Paecilomyces has not yet been considered a health problem in laboratory animals. However, this agent known as a 'spoiler' of fruit beverages and other foodstuffs is an opportunistic pathogen especially in immunocompromised humans. Since 1985, we have isolated Paecilomyces, most probably P. variotti, from six laboratory animal species, mainly rats. In about 90% of cases the organism was localized in the respiratory tract and there are some other findings favouring the hypothesis of an airborne infection. During this long observation period no consequences for the health of rats in one closed 'infected' SPF breeding unit (A) could be observed. In a controlled histological study on five infected rats, no lesions attributable to this mycotic agent could be detected. However, a self-limiting spontaneous outbreak of papular skin lesions associated with Paecilomyces was observed in a breeding colony (F) of hairless mice. The role of this fungus in an acute outbreak of respiratory signs in another colony of conventional rats (B) was considered to be secondary. Bearing in mind its occasionally harmful role in humans, relatively high resistance to disinfectants and toxigenicity, this new agent should be monitored and considered a potential health risk for laboratory animals.

The isolated perfused bovine udder skin (BUS) model was developed for studies concerning percutaneous absorption of pharmaceutical substances (Kietzmann et al., 1993). Additionally this in vitro method provides new possibilities for the assessment of the skin irritation potential. The comparison of the prostaglandin E-2-concentrations and MTT values of untreated. control sites obtained simultaneously to treated skirt sites showed the unimpaired vitality during the perfusion period of 20 individual bovine udder studies for assessment of skin irritation. Furthermore the results reveal no seasonal influences on the suitability of the organs perfused.Out of a number of tests concerning body care ingredients and formulations the results of two surfactants widely used were selected. Sodium lauryl sulfate (SLS) and alkyl polyglycoside (APG) were applied on the udder skin with low concentrations of 3% and 10% active substance, respectively, under occlusive conditions for 1 h and 5 h. The biological effects in the epidermal and dermal layers were characterized by means of prostaglandin E-2 assay and methyl tetrazolium salt dye conversion. The two surfactants could be clearly differentiated. The skin mildness of APG concerning cytotoxicity and synthesis of eicosanoids (e.g. irritancy after exposure up to 5 h) was proven in conformity with human studies.

Tests on Zeolithe A, a sodium aluminium silicate developed as a substitute for phosphates in detergents, were designed to investigate the safety of exposure to the material, or to detergents containing it, either under industrial conditions encountered during manufacturing processes or as a consequence of domestic use. The test programme included oral studies (acute, subchronic and long-term carcinogenicity tests and absorption measurements), and dermal, ocular and inhalation studies on the silicate alone and on appropriate detergent formulations, as well as studies of possible silicogenic activity and metal-complexing potential and measurements of dust generation and particle-size distribution. These studies did not produce any evidence to suggest that levels of domestic and industrial exposure resulting from the projected use of Zeolithe A in detergents would present any hazard to health. Zeolithe A did not induce silicotic tissue reactions and when incorporated into detergent formulations did not increase the liberation of fine dusts.