Abstract:
The invention relates to a coloured plaster cover that can be used, e.g., with children, in the case of irritations (formications, burns and itches) resulting from contact with stinging nettles or similar irritations.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This is a continuation application of PCT/EP01/05603, filed May 16, 2001, which is incorporated herein by reference in its entirety, and also claims the benefit of German Priority Application No. 100 24 396.7, filed May 17, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The invention relates to plaster preparations that can be used in the case of irritations (formications, burns and itches) resulting from contact with stinging nettles or similar irritations.  
         BACKGROUND OF THE INVENTION  
         [0003]    Skin irritations such as those caused by mosquito bites or contact with stinging nettles or jellyfish are invariably found to be unpleasant and troublesome. The skin irritations described in the present patent specification are all reactions involving slight reddening, weals, blisters but not pathological states such as high-degree sensitisation resulting in anaphylactic shock or the secondary formation of granulomas in the clinical picture of prurigo. The skin irritations referred to here, which are to be treated with the product according to the invention, chiefly occur after time spent outdoors, for example as occurring during children&#39;s play in woods, fields or at the edge of water but also during summer holidays or in hot resorts, or while playing sports although they may also be acquired otherwise. The skin irritations described above should be interpreted as follows in medical terms.  
           [0004]    According to textbooks (e.g., Jung, Dermatologie, 1991), minor irritation at the nociceptors of the skin produces itching while more serious irritation causes pain. Itching may also be a reaction to chemical, mechanical or thermal stimuli. This results in weals and/or urticaria through the effect of chemical substances such as from insect bites (e.g., histamine from mosquito bites, apamin from bee stings, stinging nettles etc.), allergic immune reactions to chemical substances; the effect of pressure and/or rubbing (e.g. with a paper clip or a wooden spatula, the rubbing of fine hairs), from heat (sport, heated pads) and from light (sunburn). An itchy weal and/or urticaria shows all the signs of irritation such as reddening, swelling, heat, “pain” or itching and is due to the cutaneous release of histamine. Itching has not been fully explained in medical terms and always involves a subjective, in some cases psychological, element.  
           [0005]    There have been a number of reliable remedies for itching on the market for some years. Here use is generally made of cooling gels and sticks which contain antihistamines in addition to cooling through the evaporation of alcohol or water. Use is also made of isoprenaline in powder or cream form, something which like the counter-irritant crotamiton is not recommended in the long term due to skin irritation, apart from the fact that the effect cannot be verified or explained in rational terms. The disadvantage of these topical formulations is their brief action, something which means that the application has to be constantly renewed. In addition, the insufficient length of action may result in the bites or stings becoming infected due to scratching. Skin that has become infected or damaged through scratching is much slower to heal and may scar. Then there are treatments involving oral antihistamines but they are not the preferred choice for such discomfort, which cannot be described as being pathological in nature, and have the side effect of impairing the ability to react due to sedation.  
           [0006]    The patent specification DE 19833177 A1 describes how the application of a plaster can be very effective against the consequences of insect bites or contact with stinging nettles if a certain composition is used for the base and inactive ingredients and if it is ensured that the substances used have prolonged contact with the part of the skin injured and/or concerned and scratching is simultaneously prevented. The plaster described therein contains a combination of menthol and a local anaesthetic of the ester type (benzocaine).  
         SUMMARY OF THE INVENTION  
         [0007]    The invention relates to plaster preparations that can be used in the case of irritations (formications, burns and itches) resulting from contact with stinging nettles or similar irritations. In particular, the plaster preparations include the substances menthol, thesit and tincture of plantain. The preparation diminishes the irritant effect, which manifests itself particularly in formications, itches and burns, following contact with stinging nettles and insect bites.  
         DETAILED DESCRIPTION OF THE INVENTION  
         [0008]    Surprisingly, a biological double-blind placebo-controlled laboratory study, which tested various formulations using standardised mosquito bites ( Aedes aegypti ), has shown that the existence of the local anaesthetic of the ester type (benzocaine base) is not necessary. It has been discovered that the local anaesthetic of the ester type can be replaced by adding 1% tincture of plantain to achieve the same effect. In the biological test involving  Aedes aegypti  mosquitoes (bred pathogen-free by the University of Bonn/Parasitology) 2-4 insects were positioned per subject on the lower arm of 4 volunteers using a glass cylinder until at least 1-2 bites had occurred on each underarm. As soon as the subject experienced itching, the bites were measured and covered with plasters on both lower arms (blind randomised test). The subjects were then questioned about their perceptions 10, 20 and 30 minutes after application. Two hours after application the plaster was removed and the size of the bite measured. The following formulations were tested.  
                                   Formulation   Active ingredients (level in adhesive matrix)                   A   Menthol (5%), benzocaine (8%), polidocanol (8%)       B   Menthol (5%), extract of plantain (1%), polidocanol (8%)       C   Menthol (5%)       D   Placebo                  
 
           [0009]    The following result was observed:  
                                       Formulation   Itching   Reddening                   A   Abated after 10 min, no itching   Reduction in diameter by           after 20 min   approx. 0.5 cm       B   No itching after 20 min   Reduction in diameter by               approx. 0.5 cm       C   Abated after 30 min   Partial reduction in               diameter by approx. 0.5               cm       D   Unchanged after 30 min   Reduction in diameter by               approx. 0.5 cm                  
 
           [0010]    As local anaesthetics are also known to be capable of causing contact allergies and the addition of benzocaine is not permitted for subsequent distribution as a cosmetic product, the formulation was developed further without a local anaesthetic specifically for use with children.  
           [0011]    In children, covering the irritation with a plaster has a pronounced psychological effect. For this purpose the cover must appeal to children in terms of appearance. This can be achieved for example by printing on popular cartoon figures (Sesame Street, Pooh Bear, Teletubbies, etc.) that can be applied to the backing foil using the scatter printing process. Another option is plain-colour inking. As this would necessitate ordering from the foil supplier, checking and stocking several backing foils in different colours, a logistically and economically more favourable variant was developed whereby the plaster formulation itself can be coloured by adding non-toxic and cosmetically suitable dyes. The use of a transparent backing foil then produces coloured plaster covers which appeal to children and can be used to treat skin irritations after insect bites, contact with stinging nettles etc. Here it is important to use dyes that are physiologically harmless, dissolve in the plaster formulation and do not leave any discolouration on the skin when in contact with it. Specialists can then produce plasters in virtually any colour desired (yellow, orange, red, turquoise, green, etc.). Amaranth is, for example, not suitable as it does not dissolve in solvent-based acrylate adhesive bases, or methylene blue as it dyes the skin blue when in contact with it. It may be useful to also add titanium dioxide besides the dye to intensify the colour of the transparent plaster.  
           [0012]    The present invention will be further described by the following non-limiting examples that demonstrate formulations according to the invention. 
       
    
    
     EXAMPLE 1  
       [0013]    To produce 1800 cm 2  of a yellow plaster laminate according to the invention on a laboratory scale 1.385 g menthol, 1.440 g thesit and 4.5 g tincture of plantain 4%, 43.927 g Durotak® 87-2852 and 2.3 ml ethanol 96% are mixed and added, followed by 323.5 mg beta-carotene, and then homogenised by stirring. The paste is spread with a scraper on a siliconised polyester foil in a wet layer of 400 μm to produce a surface weight of 100 g/m 2  after drying. After laminating with Cotran # 9720 a bright yellow plaster 4.0 cm 2  in size contains 1.5 mg menthol.  
       EXAMPLE 2  
       [0014]    To produce 1800 cm 2  of a red plaster laminate according to the invention on a laboratory scale 1.385 g menthol, 1.440 g thesit and 4.5 g tincture of plantain 4%, 43.927 g Durotak® 87-2852 and 2.3 ml ethanol 96% are mixed and added, followed by 212.5 mg iron (III) oxide, and then homogenised by stirring. The paste is spread with a scraper on a siliconised polyester foil in a wet layer of 400 μm to produce a surface weight of 100 g/m 2  after drying. After laminating with Cotran # 9720 a bright red plaster 4.0 cm 2  in size contains 1.5 mg menthol.  
         [0015]    The above examples can of course also be produced without dyes to permit usage by adults, who can then directly see the soothing therapeutic effect of the plaster on the skin irritation through the transparent plaster, and to also offer relief for skin irritations in the facial area as discretely and inconspicuously as possible in cosmetically acceptable terms.  
         [0016]    There are also other plaster bases known to the specialist such as hot-melt adhesives, silicones, rubbers and water-based systems although it is necessary to re-adjust the dyes to them in each case.