DE10026571A1 - Compositions used for preventing the damaging effects of sunlight, especially on the skin, comprise astringent substances in a specified amount - Google Patents

Abstract

Sunscreen compositions contain 2-5 wt.% of astringent substances (I).

Description

The invention relates to the use of astringent substances as Sunscreen. Sunscreens in general are used for protection the human skin against the pathological effects of Sunbeams. As a pathological sun reflection of the human skin are understood, the reddening of the skin (erythema solare), the sunburn (the second degree burn = microscopic or macroscopic Blistering), premature skin aging (presenile skin atrophy), Cornifications (light keratoses) and skin cancer (basalioma, spinalioma, Melanoma). Since the studies by Fitzpatrick (Fitzpatrick, T. B., et al. "Sunlight and Man", Univ. of Tokyo Press, Japan 1974) generally becomes the Take the view that such pathological skin changes different by type due to the short-term or long-term exposure to UV Radiation from the sun is caused by the skin type of people decisive for the ability to react, d. H. Response time and type of response, is to be held responsible.

As an argument for the alleged predisposition of the white race (Caucasians) their light, pigment-poor skin is mentioned, because of their Melanin deficiency defenseless against sunlight in contrast to the dark pigmented skin and its sun tolerance. There will be six skin types differentiated. To prevent such skin damage from sunlight So-called sunscreens and sunscreens were developed around the world and put on the market. A distinction is made between physically effective and chemical sunscreens. Physical consist mainly of Minerals, they reflect the sun's rays and are said to be the Prevent radiation penetration into human skin. They derive from the painting of the Australian Aborigines, but have practically none Market importance, since the achievement of an effective cosmetic protective layer is not justifiable. Chemical sunscreens are derived from the p- Aminobenzoic acid, its derivatives, but also cinnamic acid derivatives and Benzophenone are used. The market volume of the chemical Sunblocker has been in the hundreds of millions in Germany for years, which indicates their distribution in the population.

Nevertheless, in medical statistics, in dermatological Specialized publications and in the general press with emphasis and steadily Repetition not only called the dangers of exposure to sunlight, but especially noted that the number of those caused by the sun Skin cancers have repeatedly doubled.

The "sunscreens" have in common the absorption of UVA and / or UVB in different intensities. Their protective effect is with the Standard term "protection factor" or SPF determined and specified (Colipa, "SPF Test Method", The Europe Cosm. Toilt. a. Perfume Ass., Brussels, Belgium 1989; Rohr, M., Schrader, K., "The determination of the sun protection factor according to COLIPA, Parfum und Kosmetik, 1998, 5: 5-12). After initially used Protection factors "2" or "3" in the fifties and sixties of the past century, today "sunscreens" are with the factor "30" to "50" marketable, which proves that the so-called Sun protection effect of these products for a real sun protection human skin is insufficient. Further facts emerge from these facts contradicting findings: the "lighter" or more colorless the surface of one The medium with a liquid or solid consistency, the less it absorbs radiation longer than 300 nm, the darker, more colored it is (for example black), the more its surface absorbs the radiation. It follows from this in contrast to Fitzpatrick's thesis (Fitzpatrick, ibid.) that the bright, because Skin poor in pigment absorbs less radiation from the sun than that of the sun Black.

In an investigation of the sun behavior of rural African Schwarzer has been proven (Weber, G., "The skin color does not matter more ", TW Dermatologie, 1994, 24, 78-83) that this is just as sun-intolerant at the end of winter are like Caucasians that only the erythema solar at The former because of the basic color of their skin is not the same as Reddening of the skin is recognizable but the systemic reaction of the "sunstroke" (Intracranial pressure symptoms) manifests itself more strongly in black than in Caucasian. The consumption of "sunscreens" by colored people corresponds (in South Africa) quantitatively that of the Caucasians.

The doctrine of the carcinogenic effects of UVA and / or -B will invalidated by: 1. There is no experimental study on that human skin developed a carcinoma through exposure to UVA or -B alone or UVAB arises; 2. the worldwide therapeutic use of UVA, even using light sensitizers like 8-methoxypsoralen, since about 40 years, 3. has just as little led to the development of carcinoma as that Use of the sunbeds that have existed for just as long; 4. you The proportion of UVB radiation is 4%, in sunlight 2%; 5. although the essential higher UV radiation intensity with the use of equipment not proven Carcinogenicity is the 2% UVB radiation component of sunlight not only carcinogenicity but also provocation of malignant melanoma charged; 6. in a ten-year study by the U.S. Navy (Garland, F. et al., "Occupational Sunlight Exposure on Melanoma in the US Navy," Arch. Environ. Health, 1990, 45, 5, 261-266) suffered (for every 100,000) 10.6% of the Melanoma on the lower deck, but from the upper and lower deck employed 7%.

Overall, these arguments show that neither the sun's UV radiation nor the UV-blocking sunscreens have a pathogenic or preventive effect for human skin. Still, the causation is from Sun damage to the skin through to carcinoma undisputed.

Infrared (IR) together with the heat-transporting colors have the largest share of global radiation with approx. 70%. In contrast to UV radiation, evidence and arguments for the carcinogenic effect of IR have long been available (Weber, ibid; Weber, G., Sun protection factor increases the risk of skin cancer, hautnah derm, 1995, 11, 139-144; Weber, G ... "Tanning - Not Burning", close derm, 1997, 2, 2-5, Wiskemann, a et al, "Connective tissue and Carcinogenesis by radiant heat", 2 ^nd Congress Europ Soc Photobiol, in September 1987... , Padova, Italy). The fact that none of the UV blockers available on the market has a protective effect against thermal radiation explains their failure as a prevention of long-term sun damage. Therefore, the rapid increase in carcinomas and melanomas - despite the intensive use of sun protection agents and education of the population - is also due to the erroneous assumption that sun protection factor X enables X times longer exposure to the sun without risk. The de facto result is that the exposure to facultative carcinogenic thermal radiation is increased by this factor X (Weber, ibid.).

The invention is therefore based on the object of providing light protection create effective local prophylaxis against exposure to light and the pathogenic effect of light on the human skin unfolds and on Place of its application a preventive protection against the pathological Solar radiation supplies.

This task is accomplished through the use of astringent substances solved according to the attached claim 1. More, preferred Refinements are the subject of the subclaims.

It has been known since the 1920s that the human skin thickens when exposed to tanning (Guillaume, A., "Lichtschwiele", Bull. Soc. Med. Hop. Paris, 1926, 42, 1133), because the cells of the horny layer, the top layer of skin, increase, what is referred to as "light callus". The normal, i.e. not thickened The horny layer of the skin (approx. 25 µm) absorbs 20% UVA, 55% UVB and 70% IR (Raab, W. Lichtfiebel, ". Edition 1990, Gustav Fischer, Stuttgart, New York), from which it can be seen that their thickening, the light callus, is largely the Solar radiation prevents penetration into deeper, germinative skin cells. That also explains why the skin's sun tolerance with the Getting used to the sun (i.e. callosity) increases.

In the animal kingdom, too, the light callosity serves to protect against thermal radiation. The invention proposes the use of astringent substances in order to artificially create a callosity as protection against the action of the heat rays of the sun on the human skin. "Astringents are substances which, when they act on mucous membranes (and wounds), cause the superficial layers of protein to precipitate to seal and slightly shrink the tissue. They are indicated for the local treatment of inflammatory mucous membranes" (Kuschinsky, G. et al., Pharmakologie und Toxikologie , Georg Thieme Verlag, Stuttgatr, New York, 1981). A distinction must be made between two groups: 1. vegetable extracts containing tannins and 2. dilute solutions of metal salts (e.g. AgNO ₃ ).

The use of astringent substances according to the invention relates to neither the mucous membrane nor wounds and is not a therapeutic agent. the inventive application of astringent copies has the Task, the penetration z. B. the heat radiation of the sun in the The horny layer of the human skin is reduced in such a way that it becomes one Sunscreen against the penetration of solar radiation into the germinative epidermis. Evidence of heat radiation inhibiting Effect of astringent copies as an object of the invention described below.

Brief description of the figures

Fig. 1 shows a schematic representation of processes on the skin surface that occur when irradiated with electromagnetic waves;

FIG. 2 shows reflectance spectra of the skin;

FIG. 3 remission spectra similar to FIG. 2; FIG.

FIG. 4 shows reflectance spectra similar to FIG. 2 and 3;

Fig. 5 comparative reflectance spectra; and

Fig. 6 is a schematic view about the regression of a Bestrahlungserythems.

Investigation method

When electromagnetic radiation hits the surface of the skin, various physical processes take place , as shown in FIG. 1. The radiation that has penetrated the epidermis can be measured as remission, provided that it is not required by the human (hypothermic) organism. The less heat a person needs, the more he radiates the absorbed heat. Every solar radiation, including UVA and -B, is processed as heat in the organism. With the measurement of their remission, the reflection is determined at the same time. The measurements are carried out with a reflectance spectrophotometer. These are divided into two areas, that of stimulating the sample to remission and that of registering the remitted radiation. Two xenon short-arc lamps (model LPS 220) for excitation and irradiation with UV, visible and IR radiation (800-2500 nm) with a maximum output of 75 watts generate a continuous spectrum from UV to visible light and IR. The radiation from one xenon lamp is spectrally broken down in the double-grating monochromator (model 102). The radiation from the second xenon lamp is split into two beams by means of an Indo-1-dichroic (mirror 455 nm, bandpass filter 485/10 nm and 405/10). _{A BaSO 4} spectrum is registered as a measure of 100% skin remission, with which all remission spectra are corrected. The remission effect consists of absorption and remission of the incident radiation. The SFP is determined according to Colipa (ibid.). The subjects were selected according to Fitzpatrick (ibid.). In addition to the UV evaluation customary in the Colipa test, the task of determining the IR according to the invention using the second xenon arc lamp was compared to the irradiation effect of UV, visible light and IR.

Testing, application and results of the invention Investigation of astringent substances

The investigation of astringent substances according to the invention had the task of showing which light-protecting properties these on Example of tannin, Tamol (Synthetic tannins), for comparison with Have aluminum lactate, aluminum chlorohydrate and Colipa standard.

The remission measurements were carried out on the back of 10 test persons and averaged twice per measurement. FIG. 2 shows the remission spectra of the skin before and after application of the standard and 5% tannin solution. FIGS. 3 and 4 show that the tannin tannin alone causes an increase in absorption at around 320 nm and in the IR. In contrast to placebo and tamol, the use of a tannin solution for 14 days shows a constant increase in absorption, but no increase ( FIG. 5).

The investigation of the regression of the radiation erythema in 20 test persons due to tannin in comparison with the placebo revealed a significantly faster resolution of the erythema due to tannin, which shows the preventive protective effect of tannin ( FIG. 6).

Examples of other astringent substances and model formulation

The following composition was used as the basic formulation of an emulsion, as it is basically known to the person skilled in the art, in the investigations described above:

Paraffinum perliquidum 15.0% by weight Pentylene glycol 5.0% by weight Cetearyl alcohol 3.3% by weight DEA cetyl phosphate 2.0 wt% Disodium EDTA 0.1 wt% water rest

This basic formula was used as a placebo while making comparisons with Model recipes were carried out, which additionally 3 or 5 wt .-% tannin contained as an astringent substance.

As examples of other astringent substances used in the context of present invention can be used, aluminum lactate, Aluminum chlorohydrate and tamol are mentioned, but none of them Restriction to these connections is provided.

Claims (7)

1. Use of astringent substances for the preparation of a Composition for the prevention of exposure to sunlight or Harmful wavelengths caused by sunlight Effects. 2. Use according to claim 1 as a sunscreen for the human skin. 3. Use according to claim 1 or 2, characterized in that the composition in the form of solutions, creams, ointments, Lotions, sprays, powders or emulsions. 4. Use according to any one of claims 1 to 3, characterized in that the composition as astringent substance tannin, tamol, Contains aluminum lactate or aluminum chlorohydrate. 5. Use according to one of the preceding claims, characterized in that the content of astringent substance is more than 1% by weight, preferably 2 to 5% by weight. 6. Use of astringent substances for the preparation of a Composition for the artificial creation or thickening of a Callosity. 7. Use of astringent substances according to claim 1, whereby the wavelengths of sunlight transport heat Rays, UVA, UVB or IR rays are.