CH699552B1 - Dermatologically effective topical composition, in particular for the prevention and treatment of skin diseases. - Google Patents

Abstract

A dermatologically active topical composition, in particular for the prevention and treatment of skin diseases, comprises a textile carrier of cellulosic fibers which are provided with an acidic surface layer. The wash-resistant acidic coating can be prepared by esterification with a polycarboxylic acid, in particular citric acid.

Description

Technical area

The invention relates to a dermatologically active topical composition according to the preamble of claim 1, a garment according to claim 5 and the use of a polycarboxylic acid according to claim 6.

State of the art

Diseases such as atopic dermatitis, aging skin, diabetes and occupational eczema (because of heavy sweating or moisture exposure), various causes such as a reduced pH buffering capacity of the skin, impaired or destroyed water vapor barrier of the skin, infections by penetrating contact allergens or a have altered microbiology of the skin (colonization by staphylococci). Typical symptoms or manifestations include itching, redness, eczema and psoriasis. In the Swiss population, for example, around 16% of young children suffer from atopic dermatitis and about 0.5% of the total population from psoriasis.

The influence of textiles as a cause of skin irritation or the ability to preventive and therapeutic by targeted adaptation of clothing, has long been studied (Elsner P. et al., Textile and the Skin, Current Problems in Dermatology, Vol 31, Karger, 2003). So far, studies on fiber morphology, dyes, pesticides, auxiliary textile chemicals (e.g., plasticizers, optical brighteners) and detergent ingredients (enzymes, surfactants) have been in the foreground. On the other hand, a parameter hardly considered until now is the pH value of textiles. Compared to the physiological pH of the skin (about 5.5 to 6.5, depending on age, sex and body zones), textiles usually have a significantly higher pH of about 7 to 9, which is also strongly influenced by the nature of the skin Care (washing) is affected.

Furthermore, it is known that healthy skin is hardly influenced by fluctuating pH values of the clothing in the range between 4.6 and 10.1 (Matthies W., Influence of the pH on the Skin Compatibility of Cotton Textiles, Dermatoses, 1993, 41, 97- 100). By contrast, the influence on diseased skin is unknown. On the other hand, the stimulating effect of slightly acidic substances, e.g. Lactic Acid and Various Amino Acids in Healing of Diseased Skin (Schmid-Grendelmeier P. et al., Basic / Concomitant Therapy and Prevention of Dermatoses, Consensus Statement, International Journal of Medical Education, No. 38, Nov 2005). In a double-blind, placebo-controlled study, pH-low latex gloves were found to be significantly better at maintaining skin barrier than biophysical measurements compared to regular latex gloves (Mirza R. et al., A randomized, controlled double-blind study ofthe effect of wearing coated pH 5.5 latex gloves as compared to standard powder-free latex gloves on skin pH, transepidermal water loss and skin irritation, contact dermatitis, 2006, 55, 20-25).

EP 0 138 179 A2 describes pH-regulating materials which are formed from a uniformly acidic, chemically modified viscose fiber and are provided in particular for the production of welding pads or shoe inserts. The disadvantage here is that materials that are chemically modified holistically as in the viscose, change their material properties emphatically. Thus, there is usually a greatly increased hydrophilicity, which is undesirable for clothing textiles because of increased absorption of perspiration, as well as a reduced durability as a result of damage to the cotton fiber by the strongly acidic substances used.

The also already proposed purely physical adsorption of acidic substances on textile fibers has the disadvantage that the residence time on the fiber is sufficient at most for a disposable product. In particular, such products can not be washed.

Presentation of the invention

The object of the invention is to provide a new means for the prevention and treatment of skin diseases.

This object is achieved by the defined in claim 1 dermatologically effective topical composition. This comprises a textile carrier of cellulose-containing fibers, wherein the fibers are provided with an acid-acting surface layer which can be prepared by esterification with a polycarboxylic acid, wherein the polycarboxylic acid is selected from malic acid, tartaric acid and citric acid. Preferably, the composition according to the invention has, after up to 20 washes with a pH-neutral detergent, a pH of at most 6.5 measured on its surface.

The composition of the invention is suitable for skin-contacting or hanging up and allows to set or maintain a physiologically advantageous pH at the skin surface with a textile part. The composition is particularly suitable for preventive and / or therapeutic use in patients with pathologically altered water vapor barriers of the skin. As an important application eczema, psoriasis or dermatoses in endangered persons should be avoided or their healing should be supported.

By suitable choice of the reaction conditions can be achieved that the individual Polycarbonsäuremoleküle are esterified via one (or optionally more) of its carboxyl groups with the cellulose, but next at least one free carboxyl group. Accordingly, in the context of the present invention cellulose-containing fibers of a textile carrier are provided by treatment with a polycarboxylic acid with a superficial coating which still has free acid groups. Due to the covalent attachment of the Polycarbonsäuremoleküle to the cellulose framework, the acidic coating is very durable and durable.

In contrast to the viscose process, in which substantially all of the cellulose material is permanently chemically modified, in the composition according to the invention only a near-surface layer of the cellulose-containing fibers is modified. Therefore, the textile handle is not affected, and there are no changes in tear strength, seam slip resistance, tear resistance and residual shrinkage. When used in garments, a similar behavior is to be expected in thermo-physiological terms as with cotton without acid coating.

The inventive composition can be produced by a simple method, which is particularly applicable to ready-finished cotton textiles.

Advantageous embodiments of the invention are defined in the dependent claims.

In principle, different types of cellulose-containing fibers come into consideration for the textile support, with cotton fibers being particularly preferred.

Polycarboxylic acids according to the invention are the dicarboxylic acids malic acid (2-hydroxyethane-1,2-dicarboxylic acid) and tartaric acid (2,3-dihydroxybutanedioic acid). However, a particularly preferred polycarboxylic acid is citric acid (2-hydroxypropane-1,2,3-tricarboxylic acid).

Although the composition according to the invention is suitable both for single use and for multiple use, its washing resistance in particular opens up various possible uses as articles for multiple use.

As expected, the pH immediately after application of the acidic coating depends on the dissociation constants or pKa values of the selected polycarboxylic acid. For example, after being supplied with citric acid, a pH of 2.0 to 3.0 was determined according to the procedure described below. Since such low pH values are unsuitable for topical application, prior to the first (or only) use, an increase in the pH must be raised to a physiologically acceptable range of about pH 5. This can be achieved, for example, by a washing operation carried out by the supplier. Alternatively, the acidic coating can be carried out with a weaker polycarboxylic acid, so that from the outset not so low pH values are achieved.

The inventive composition can be configured in various ways. For example, it can be used as bedding, hygiene products, wipes, baby diapers, incontinence products, but also for plasters, wound dressings and gauzes. In an advantageous embodiment, the inventive composition forms at least one skin-facing layer of a garment, which may be, for example: pants, T-shirt, underwear, shirt, blouse, glove, headgear and the like. Especially with such multiple-use articles, the above-mentioned wash resistance is particularly important.

According to a further aspect of the invention, a polycarboxylic acid, preferably citric acid, is used for the preparation of a dermatologically active topical composition according to the invention for the prevention and treatment of skin diseases.

Brief description of the drawings

Embodiments of the invention are described below with reference to the drawings, in which: <Tb> FIG. 1 <sep> the measured pH of two uncoated fabric samples A (comparative examples) and of two acid-coated fabric samples B (examples), either unsprayed (designation Aobzw Bo) or once rinsed with deionized water (designation As or Bs), in unwashed condition (open symbols) and after a standard wash (filled symbols); and <Tb> FIG. 2 <sep> the measured pH of the fabric sample Bo during 20 washes.

Detailed description of the invention

Production of textile carriers with acidic coating

The experiments described below were carried out with wrinkle-free cotton fabric samples of size DIN A3.

In order to have a basis of comparison, some of the samples were not provided with an acidic coating. These patterns are hereinafter referred to as "uncoated" and marked with the symbol "A".

The remaining samples were treated as follows: Each sample was placed in a 250 mL bottom flask and mixed with 80 mL of deionized water. To this was added 2.1 g (10 mmol) of citric acid monohydrate (C6H8O7⋅H2O, M = 210.14 g / mol) and 2.12 g (20 mmol) of sodium hypophosphite monohydrate (H2NaO2P⋅H2O, M = 105.99 g / mol), the mixture Boiled under reflux for 10 min and then left to cool. Then the fabric was taken out, pressed by hand and allowed to air dry. Subsequently, the samples were treated for 3 min at 130 ° C in a warming cabinet. The samples thus treated are hereinafter referred to as "coated" and marked with the symbol "B". The samples were rinsed briefly by hand with about 200 mL of deionized water three times, squeezed by hand and allowed to air dry.

To clarify the question of whether the quality of the acidic equipment depends on the cleanliness or the presence of flushable components in the delivered fabric samples, half of the fabric samples were pre-rinsed in a standard wash with no detergent and with deionized water. In the case of the fabric samples B, the acidic coating was then applied, in the case of the fabric samples A, no further treatment steps were carried out.

washing tests

All washing experiments were carried out with a pH neutral detergent and local tap water at the EMPA St. Gallen. The pH of the tap water ranged from 7.5 to 8; After admixing the pH neutral detergent, the pH was about 7. For all experiments, the same standardized washing procedure was used, here referred to simply as "standard washing". At the same time, the "Shirts" program was carried out on a Miele Softtronic W-35-21CH automatic washing machine. This is characterized by a total washing time of 56 minutes and a nominal temperature of 40 ° C. In each case, 40 ml of pH-neutral mild detergent (Oecoplan brand, COOP) were added to about 12 liters of water. At the end of the wash, 2 extra washings were performed to remove any residual detergent.

pH measurements

The pH values indicated below were carried out with a pH meter from Courage-Khazaka (cutometer MPA 580) and a Mettler-Toledo (Mettler-Toledo) pH electrode (flat glass membrane with ground diaphragm).

To prepare a pH-neutral measuring solution, 500 ml of deionized water were mixed with 1 ml of saturated KCl. This increases the conductivity, resulting in a fast and stable pH signal. During the actual measuring procedure, 0.1 ml of the pH-neutral measuring solution was added to the textile and then the pH value was determined immediately by placing the two-dimensional pH electrode (20 seconds waiting time until stable, 3 to 5 repetitions per textile sample). The absolute accuracy of the pH measurements was determined to be ± 0.2 pH units. In the following illustrations, only the mean value of a series of measurements is shown.

Results after a single standard wash.

In Fig. 1, the results of four different types of fabric types are shown, namely: <tb> Ao <sep> uncoated, not rinsed (= Comparative Example 1) <tb> As <sep> uncoated, rinsed (= Comparative Example 2) <tb> Bo <sep> coated, non-rinsed (= Example 1) <tb> Bs <sep> coated, pre-rinsed (before application of the coating) (= Example 2)

The lower set of dashes (open symbols) represents the measured pH of the unwashed patterns, the upper set of dashes (filled symbols) represents the pH after a single standard wash ("washed").

From Fig. 1 shows that the pre-rinsing of the pattern before equipping with the acidic layer has no significant effect on the pH. The uncoated samples had a slightly acidic pH in the range of about 6.3 to 6.8 before the first wash, but this increased to 7.0 even after a single wash. In contrast, the pH of the coated samples prior to the first wash in the highly acidic range was about 2.3 to 2.5 and increased to 5.8 to 6.0 after a single wash, which is in the desired physiologically acceptable and preventive or curative effective range.

Washable over 20 standard washes

A number of Bo type patterns, i. with an acidic surface layer applied to the non-pre-rinsed fabric swatch was subjected to an extended wash-resistance test. The samples were washed various times with the standard washing procedure described above (1, 5, 10 and 20 times), then their pH was determined. The following pH values were measured (see FIG. 2): immediately after application of the acidic layer: pH 2.5 Wash once: pH 6.0 5 times washing: pH 6.2 Wash 10 times: pH 6.3 Wash 20 times: pH 6.3.

Closing remarks

The wash series over a total of 20 standard washes has shown that the pH is still in the target range (5.5 to 6.5) even after 20 washes, but a slight and constant increase is measurable with each wash. Possible causes include hydrolyzing the acidic molecules (breaking the bond to the cotton) favored by the wash liquor, mechanical aging of the fabric (and associated detachment of wrinkle-free finish, fillers, dyes, etc.) or deposition of ingredients from the detergent Fragrances, fillers, surfactants, etc.).

Pre-rinsing the delivered cotton samples with deionized water (by EMPA Testmaterialien AG) did not have much impact on the quality of the following equipment with citric acid. Nevertheless, it must be ensured in an industrial process that no water-soluble residues from the production (finishing) or refining (wrinkle-free equipment) are present before equipment with acidic molecules. These would undoubtedly reduce the durability of further functionalization with acidic groups.

Basically, basic washing powder or detergent should be avoided because the acidic character of the textile is otherwise lost. It should also be noted that some detergents contain a variety of enzymes, fillers, optical brighteners, polymers, perfumes, antistatic agents, etc. Such detergents are unsuitable because the deposition of said additives on the surface of the fabric would result in an undesirable change in pH.

Claims (7)

1. A dermatologically active topical composition, in particular for the prevention and treatment of skin diseases, characterized in that it comprises a textile carrier of cellulose-containing fibers, wherein the fibers are provided with an acidic surface layer, which can be prepared by esterification with a polycarboxylic acid, wherein the Polycarboxylic acid is selected from malic acid, tartaric acid and citric acid. 2. Composition according to claim 1, characterized in that the textile carrier is formed from cotton. 3. Composition according to claim 2, characterized in that the textile carrier is equipped wrinkle-free. 4. Composition according to one of the preceding claims, characterized in that the polycarboxylic acid is citric acid. 5. Garment having a skin facing with a composition according to any one of claims 1 to 4. 6. Use of a selected from malic acid, tartaric acid and citric acid polycarboxylic acid for the preparation of a dermatologically active topical composition according to claim 1 for the prevention and treatment of skin diseases. Use according to claim 6, wherein the polycarboxylic acid is citric acid.