WO2009071251A2

WO2009071251A2 - Skin model

Info

Publication number: WO2009071251A2
Application number: PCT/EP2008/010146
Authority: WO
Inventors: Daniela Prinz; Gerd Kutz; Christiane Bruns
Original assignee: Cognis Ip Management Gmbh
Priority date: 2007-12-08
Filing date: 2008-11-29
Publication date: 2009-06-11
Also published as: DE102007059199A1; WO2009071251A3

Abstract

The invention relates to a device for testing cosmetic and pharmaceutical raw materials, comprising a membrane that is streched over a container that comprises a hydrogel as supporting base for the membrane.

Description

skin model

Field of the invention

The invention is in the field of devices for testing cosmetic raw materials and final formulations.

State of the art

Before cosmetic raw materials or final formulations are introduced to the market, they are subjected to sensor technology tests as part of the development process. The raw materials or formulations are tested after toxicological release to volunteers. Trained subjects evaluate the sensory properties on the basis of a profile, which must be created for each substance to be tested. By way of example, reference should be made here to the methodology for determining spreadability. The area that a cosmetic oil spreads on the skin is correlated to the consumer's perceived smoothness. However, such in-vivo tests have the disadvantage that only substances that have already been evaluated as toxicologically harmless can be tested. In addition, some measurements are not technically feasible in vivo apparatus. Artificial test surfaces, z.T. also of natural origin, e.g. Pigskin, have different properties in terms of spreading behavior than human skin, and due to natural variations in material properties due to e.g. Weathering or injury to animal skin does not give reproducible test conditions.

The object of the present invention was therefore to provide a skin substitute which reproducibly simulates human skin and in which various methods for testing raw materials on the skin can be simulated.

Description of the invention

The present invention is an apparatus for testing cosmetic and pharmaceutical raw materials comprising a membrane which is stretched over a container containing a hydrogel as a supporting substrate for the membrane.

membrane

As a membrane, which is stretched over the hydrogel as a supporting substrate, are preferably collagen membranes as they are used in the food industry. These are preferably collagen membranes which can be used as sausage pelts. By way of example, mention may be made here of membranes made by Naturin, which are marketed under the names EWD-Casing, COFFI-foil or Classic Casing.

If the surface tests carried out on the membranes are to have different surface conditions, such as e.g. Lipophilicity, surface roughness, surface tension, these can be achieved by selecting the membrane, by the choice and concentration of the gelling agent, by the use of humectants in various concentrations or by applying sebum lipids to the membrane surface.

hydrogel

As hydrogel gels can be used, which were prepared with a variety of gelling agents. In a preferred embodiment, it is hydrogels based on agar-agar, gelatin, hydroxyethyl cellulose or mixtures thereof. Particularly preferred are the hydrogels based on agar-agar, since they can be conditioned at 32 ° C, since they do not melt.

container

Suitable containers for the skin substitute are all inert containers, preferably glass containers.

Due to their dimensions, Petri dishes are used in particular.

Humectants

In order to keep the gels and the membranes attached thereto moist and usable during the test series, humectants can be added to the hydrogels. These prevent premature drying of the measuring device. Furthermore, the surface properties of the membrane can be deliberately influenced by the humectants. As a preferred humectant glycerol is considered. With respect to the hydrogels, the humectants are used in amounts of from 0.1 to 25% by weight.

test methods

Using the skin model, cosmetic and pharmaceutical raw materials can be tested before the dermatological or toxicological safety has been established. Thus, the water vapor diffusion on the surface of the skin model can be determined with the aid of a Tewameter TM210 from Courage & Khazaka, Cologne before and after treatment with a raw material or a composition, but also corneometric (determination of the hydration of the surface of the skin model, eg with the aid of a corneometer CM820 from Courage & Khazaka, Cologne) and frictiometric measurements (eg with a Fritiometer® FR 700) are possible. The spreading behavior of oils on the skin model (according to Zeidler, Fette Seifen Anstrichmittel, Vol. 87, no. 10, Dusseldorf, 1985) can also be tested and quantified. It is also possible to determine the surface energy before and after treatment with various raw materials or compositions (eg with the aid of a contact angle measuring system OCAH200 from DataPhysics Instruments GmbH, Filderstadt).

Depending on the test method, certain combinations of membranes and hydrogels have proven particularly useful. To measure the transdermal water loss (TEWL) and in the corneometry especially the skin models based on an agar gelatin or agar-agar hydrogel with EWD-Casing were suitable.

Examples

Example 1: Composition and Preparation of the Skin Substitute

Water and glycerin were heated. Gelatin was swollen for 5-10 minutes with 50g of the glycerol-water mixture.

Once the mixture had reached a temperature of 50 to 6O ⁰ C, the swollen gelatin was added, and stirred using a magnetic stirrer until the gelatin was completely dissolved.

Phenoxyethanol was added and the gelatin mass cooled. Once the mass had reached a temperature of about 40 to 50 ° C, it was filled in petri dishes, which were filled to the brim.

Gelatinization of the gelatin takes about 30 minutes to 120 minutes, depending on the temperature and relative humidity in the environment.

In the meantime, the collagen membrane for about 15min. moistened in water. As soon as the gelatin mass had sufficient gel strength, the moistened collagen membrane was freed from excess water and then stretched tightly over the gelatin surface. Below-surface air bubbles have been removed.

The conditioning was achieved in a climate chamber at 20 ° C and 80 to 90% relative humidity over 15-2Oh.

Claims

claims

1. Apparatus for testing cosmetic and pharmaceutical raw materials comprising a

Membrane that is stretched over a container containing a hydrogel as a supporting substrate for the membrane.

2. Device according to claim 1, characterized in that it is the membrane is a collagen membrane.

3. Device according to one of claims 1 or 2, characterized in that a sausage pel is used as a collagen membrane.

4. Device according to one of claims 1 to 3, characterized in that the membrane has been modified with humectants or sebum lipids.

5. Device according to one of claims 1 to 4, characterized in that a hydrogel from the group formed by agar-agar. Gelatin, hydroxyethyl cellulose or mixtures thereof.

6. The device according to claim 4, characterized in that is used as a humectant glycerol.