the present invention is based at least in part on the clinical observation that the topical application of a therapeutically effective amount of a composition comprising at least one α 1 - adrenoceptor agonist to the skin is effective in significantly reducing or preventing the redness ( erythema ), flushing and sensation of warmth and discomfort which are hallmarks of rosacea and other conditions causing discreet erythema of the skin ( e . g . acne , sunburn ), and thus provides both subjective and objective relief of signs and symptoms of these conditions . prototypical α 1 - adrenoceptor agonists include phenylepherine and oxymetazoline , but other α 1 - adrenoceptor agonist agents include , but are not limited to naturally occurring and synthetically derived compounds based on or derived from pharmacologically similarly acting chemicals , drugs or prodrugs and derivatives thereof . examples of preferred compounds which are specifically contemplated as α 1 - adrenoceptor agonists suitable for use in accordance with the present invention include , but are not limit to e . g ., the α 1 - adrenoceptor agonists oxymetazoline , tetrahydrozoline , nephazoline , xylometazoline and the α 1 - adrenoceptor agonists discussed in chapters 6 and 10 of goodman and gilman &# 39 ; s the pharmacological basis of therapeutics , tenth edition , edited by hardman j and limbird l . new york , n . y ., mcgraw - hill , 2001 , which is hereby incorporated by reference as though set forth in full herein , and in particular phenylepherine methoxamine , mephentermine , metaraminol , desglymidodrine , and its prodrug midodrine . as no prior consideration of the application of α 1 - adrenoceptor agonist to the skin has been contemplated or reported , for any indication , little is known of the cutaneous absorption or toxicology of oxymetazoline used in this fashion . the manufacturers report no significant organ damage or general toxicity in dog , cat , rabbit or mouse about dosages close to those used in man . when administered by injection subcutaneously , in rabbits , no drug related abnormalities or effects on the offspring were found . in a retrospective study in man , no association was found between the drug and congenital disorders . no carcinogenicity tests have been reported . but oxymetazoline has been used intranasaly and ophthalmicaly for decades for reducing blood flow and diminishing of swelling of the mucosa and has not been reported to effect any systemic side effects . there is no formal data on the subject , however . the excellent safety and efficacy profile of oxymetazoline when used intranasaly or ophthalmicaly to effect local vasoconstriction suggested its potential use as a topically applied vasoconstrictor to the skin for the treatment of the erythema and telangiectasias of rosacea and other erythematous conditions of the skin and has been observed clinically by one of the applicants in his clinical practice of dermatology . the local anti - erythema effect is thus observed when topically applying an effective amount of an α 1 - adrenoceptor agonist , admixed with a skin - specific penetration enhancer and a pharmacologically acceptable vehicle for topical administration without causing any noticeable systemic effects . the clinical efficacy of the applied α 1 - adrenoceptor agonist compound is predicated not only upon the agent reaching the receptors , which are located within the skin on vascular smooth muscle , but also on the pharmacokinetics of each particular receptor agonist . thus the choice and concentration of the active agent , or combination of active agents , the topical delivery system and vehicle for the active agent ( s ) are significant considerations . specifically , prototypical α 1 - adrenoceptor agonists in the present invention are tetrahydrozoline and oxymetazoline , and when included in the typical embodiment as the sole active ingredient ( sole α 1 - adrenoceptor agonist ) are preferably used in amounts of about 0 . 05 % up to about 30 %, and preferably about 0 . 001 % up to about 3 % by weight based on the total weight of the composition . where both , or an additional or different α 1 - adrenoceptor agonist is admixed , lower amounts of the active compound ( s ) might be included . additionally , the carrier or vehicle of the invention will have dramatic effects on the concentrations of the active ingredients selected . the preferred embodiments employ active ingredients in amounts effective to achieve clinical efficacy without causing systemic side effects . the compositions according to the invention may comprise all pharmaceutical forms normally utilized for the topical route of administration and known to practitioners of this art including solutions , gels , lotions creams , ointments , foams , mousses , emulsions , microemulsions , milks , serums , aerosols , sprays , dispersions , microcapsules , vesicles and microparticles thereof . the subject compositions may also be formulated as solid preparations constituting soaps or cleansing bars . these compositions are formulated according to conventional techniques . the term “ pharmacologically / dermatologically acceptable carriers ”, as used herein , means that the carrier is suitable for topical application to the keratinous tissue , has good aesthetic properties , is compatible with the active agents of the present invention and any other components , and will not cause any untoward safety or toxicity concerns . the carrier can be in a wide variety of forms . for example , emulsion carriers , including , but not limited to , oil - in - water , water - in - oil , water - in - oil - in - water , and oil - in - water - in - silicon emulsions , are useful herein . as will be understood by the skilled artisan , a given component will distribute primarily into either the water or oil / silicon phase , depending on the water solubility / dispersibility of the component in the composition . a safe and effective amount of carrier is from about 50 % to about 99 . 999 %, more preferably from about 70 % to about 99 . 99 %. the composition , if desired , can contain various known bases such as excipients , binders , lubricants , and disintegrants . if desired , it can also contain oily materials such as various fats , oils , waxes , hydrocarbons , fatty acids , higher alcohols , ester oils , metallic soaps , animal or vegetable extracts , hydrophilic or lipophilic gelling agents , hydrophilic or lipophilic active agents , pharmaceutically effective components such as vitamins , hormones , amino acids , surfactants , colorants , dyes , pigments , fragrances , odor absorbers , antiseptics , preservatives , bactericides , humectants , thickeners , solvents , fillers , antioxidants , sequestering agents , sunscreens , or any other known components and additives as long as the effects of the present invention are not impaired . examples of suitable oils includes mineral oils , plant oils such as peanut oil , sesame oil , soybean oil , safflower oil , sunflower oil , animal oils such as lanolin or perhydrosqualene , synthetic oils such as purcellin oil , silicone oils such as cyclomethicome among others . fatty alcohols , fatty acids such as stearic acid and waxes such as paraffin wax , carnauba wax or beeswax may also be used as fats . the composition may also contain emulsifying agents such as glyceryl stearate , solvents such as lower alcohols including ethanol , isopropanol , and propylene glycol , hydrophilic gelling agents including carboxyvinyl polymers or acrylic copolymers , polyacrylamides , polysaccharides , lipophilic gelling agents or fatty acid metal salts among others , hydrophilic acting agents such as amino acids , sugars , starch or urea , lipophilic active agents such as retinol or tocopherol . in some embodiments , the compositions contain one or more α 1 - adrenoceptor agonists , to act specifically on the erythematous component of the condition to be treated , admixed with another agent known to be effective in treating another manifestation of the disease state . for example , compositions consisting of anti - rosacea agents such as metronidazole , precipitated sulfur , sodium sulfacetamide , or azelaic acid , which are commonly used to treat the papular and pustular components of rosacea are combined with a dermatologically / pharmacologically acceptable form of the subject α 1 - adrenoceptor agonist to effect treatment of both the inflammatory ( papular and pustular ) and erythematous manifestations of the condition . there is currently no known composition available that succeeds in this goal . other embodiments combine one or more α 1 - adrenoceptor agonist with active agents destined , in particular , for preventing and / or treating the erythema associated with numerous other skin complaints , conditions and afflictions . examples of these agents include : 2 . antibacterial agents ( antibiotics ) such as clindamycin phosphate , erythromycin , or antibiotics from the tetracycline family . 3 . antimycobacterial agents such as dapsone . 4 . other antiacne agents such as retinoids , or benzoyl peroxide . 5 . antiparasitic agents such as metronidazole , permethrin , crotamiton or pyrethroids . 6 . antifungal agents such as compounds of the imidazole family such as miconazole , clotrimazole , econazole , ketoconazole , or salts thereof , polyene compounds such as amphotericin b , compound of the allylamine family such as terbinafine . 7 . steroidal anti - inflammatory agents such as hydrocortisone triamcinolone , fluocinonide , betamethasone valerate or clobetasol propionate , or non - steroidal anti - inflammatory agents such as ibuprofen and salts thereof , naproxen and salts thereof , or acetaminophen . 8 . anesthetic agents such as lidocaine , prilocalne , tetracaine , hydrochloride and derivatives thereof . 9 . antipruriginous agents such as thenaldine , trimeprazine , or pramoxine . 10 . antiviral agents such as acyclovir . 11 . keratolytic agents such as alpha - and beta - hydroxy acids such as glycolic 12 . anti - free radical agents ( antioxidants ) such as vitamin e ( alpha tocopherol ) and its derivatives , vitamin c ( ascorbic acid ), vitamin a ( retinol ) and its derivatives , and superoxide dismutases . 13 . antiseborrheic agents such as zinc pyrithione and selenium sulfide . 14 . antihistamines such as cyproheptadine or hydroxyzine . 15 . tricyclic antidepressants such as doxepin hydrochloride . in order to further illustrate the present invention and the advantages thereof , the following specific examples are given , it being understood that the same are illustrative and in no ways limitative . the administration of compositions containing one or more alpha - 1 adrenoreceptor agonists elicits a marked decrease or even complete disappearance of skin redness , which is manifested both in rosacea and other discreet erythemas . specifically , according to the present invention , at least one alpha - 1 adrenoreceptor agonist is formulated into a cosmetic , pharmaceutical or dermatological composition for treating skin redness of vascular origin , evident in rosacea and / or other discreet erythemas including acne and sunburn . the compositions of the invention will be , preferably , administered topically . the subjective compositions for topical application comprise a cosmetically , pharmaceutically or dermatologically acceptable medium ( vehicle , diluent or carrier ), namely a medium which is compatible with application to the skin . the present invention is directed to the use of alpha 1 and 2 adrenoreceptor agonists for treat rosacea or erythema . in one embodiment , the invention is directed to the use alpha 1 agonists such oxymetazoline hydrochloride as a vasoconstrictor for use with or without an anti - acne compound . alternative alpha 1 agonists including phenylephrine are applicable to the teachings of the present invention . the principles of the present invention are also deemed to be applicable to alpha 2 adrenoreceptor agonists such as clonidine and clenbuterol . for the purposes of this disclosure , rosacea is characterized by erythema of the face , predominantly on the cheeks , the forehead and the nose , hyperseborrhoea of the face on the forehead , the nose and the cheeks , and an infectious component manifesting acne form pustules . moreover , these indications are associated with a neurogenic component , namely , a cutaneous hyperreactivity of the skin of the face and of the neck , characterized by the appearance of redness and subjective sensations of the itching or pruritus type , sensations of burning or of heating , sensations of stinging , tingling , discomfort , tightness , etc . the preferred alpha 1 or 2 agonist used as a vasoconstrictor in the present invention is preferably used in an amount of about 0 . 01 % up to about 20 %, and preferably about 0 . 1 % to about 10 %, by weight based on the total weight of the composition . in the most preferred embodiment , the vasoconstrictor comprises an alpha 1 or alpha 2 adrenoreceptor agonist . the vasoconstrictor used in the present invention may function to remove the redness from acne areas of the skin , including oxymetazoline hydrochloride , the preferred agonist in the present invention oxymetazoline hydrochloride : the chemical formula for oxymetazoline hydrochloride is as follows : the following table sets forth the characteristics of alpha 1 and alpa 2 adrenoreceptors as used in the present invention . the present invention has been described with reference to the enclosed preferred embodiment . the true nature and scope of the present invention is to be determined with reference to the claims appended hereto .
the present invention is directed to the treatment of skin erythema as exhibited in rosacea and other conditions characterized by increased erythema of the skin . these conditions exhibit dilation of blood vessels due to a cutaneous vascular hyper - reactivity . in particular , the present invention is directed to a novel composition and method for the treatment of skin erythema using α 1 - adrenergic receptor agonists incorporated into cosmetic , pharmacological or dermatological compositions for topical application to the skin .