Assessment of in vitro dermal absorption of the kaurenic acid from Coespeletia moriziana extracts.

Espeletiinae are plants which grow above 3000 m of altitude in the Northern Andes and kaurenic acid was extracted from the leaves of Coespeletia moritziana. This compound has shown a wide range of biological activities, including cytotoxicity which is efficient in cancer therapy. The percutaneous penetration of this compound was measured in vitro using Franz cells. At appropriate intervals for up to 24h, diffusion samples were analyzed using HPLC. At the end of the test period, the amount of kaurenic acid was determined in each compartment and approximately 10% of kaurenic acid had been absorbed and was found in the skin layers.

Benzophenone-3 entrapped in solid lipid microspheres: formulation and in vitro skin evaluation.

Solid lipid microspheres (SLM), lipid-in-water formulations made from oil-and-wax mixtures, were studied concerning feasibility. SLMs were then loaded with a benzophenone-3, water insoluble UVAB-filter intended for dermal application. Microspheres were prepared by dispersion with homogenisers and investigated by polarizing micrography and scanning electron micrography. For the selected formulations, investigations on percutaneous penetration of B-3 capacity were performed "in vitro" using Franz cells. Microspheres, 5-50 µm in size, and a spherical shape were obtained from several mixtures. B-3 was added and the loading capacity of this drug in the SLM was obtained for a maximum of 5% when the lipophilic phase was 18%. The lipophilic mixture with non-ionic surfactants in the selected formulation of lipid microspheres has a favorable effect on size. The selected formulation is also cosmetically adapted and it is composed of physiological and biodegradable lipids. B-3 was released and penetrated into skin more quickly and in greater quantity than in SLM form, from vehicles containing free B-3. This work has shown that SLM is an excellent carrier for lipophilic sunscreens like B-3 in order to decrease the release and penetration rate of this UV absorber compared with B-3 in oily solution.

The "in vitro" percutaneous penetration of three antioxidant compounds.

Caffeic acid, chlorogenic acid and oraposide, a natural glycoside, are phenyl-propanoid compounds. These natural products have been reported to have antioxidant activities such as the scavenging of superoxide anions and hydroxyl radicals. These compounds could be used in the dermocosmetic field to protect the skin from oxidative stress induced by UV radiation. To this end, the permeation of caffeic acid, chlorogenic acid, and oraposide, through pig-ear skin was evaluated in vitro. The percutaneous permeation of these three compounds through pig skin was measured and compared using Franz diffusion cells. At appropriate intervals, up to 72 h, diffusion samples were analyzed using an HPLC assay. After 48 h of drug contact the permeation was also evaluated with a fluorescent microscope on vertical microtomed pig skin sections. In this study on excised pig skin, the flux value was found to be equal to 0.32 and 0.48 microgcm(-2)h(-1) for caffeic and chlorogenic acids, respectively; for oraposide the levels were below the limit of detection and the flux was not evaluated. These results were corroborated by fluorescent microscopy. Caffeic and chlorogenic acids were found in all skin sections, and these might represent a systemic activity, whereas oraposide remained in the upper superficial layer of the skin. This latter phenomenon seems to be interesting for dermocosmetic applications.

Evaluation expérimentale de l'hydratation et du pouvoir occlusif in vivo et in vitro d'excipients lipophiles et de leurs émulsions phase huile continue.

Synopsis A study was carried out on three water in oil emulsions and their respective oil-phases, petrolatum, liquid paraffin and sweet almond oil, in order to compare their occlusive properties and thus their influence on cutaneous hydration. An in vitro method using 'Patel'cells in a water-saturated atmosphere at controlled temperature enabled, in the first instance, the various emulsions and their oil-phases to be classified according to their permeability to water vapour. The results are in order of increasing degree of occlusion: sweet almond oil, liquid paraffin and petrolatum. In in vivo studies on human volunteers, the influence of the application of the same substances on transepidermal water loss (TEWL) and cutaneous hydration was measured with an evaporimeter and a corneometer, in a temperature and humidity-controlled room. Measurements were performed on the flexor side of the forearm after sodium lauryl sulphate 5% insult on six subjects at times of 0, 30, 120 and 270 min. The different oils, used pure, increased the hydration by an occlusive effect, and this was described by measurements of TEWL. On the other hand, after using the emulsions, the increase in hydration noted does not appear to involve an occlusive mechanism.