WO2009042402A2 - Composition and method for treating rosacea - Google Patents

Abstract

A composition for the treatment of skin exhibiting the symptoms of rosacea, and a method of treating the skin of an individual suffering from rosacea, are disclosed. The composition comprises a hydroxycinnamic acid and/or a methoxycinnamic acid and a suitable carrier for topical application of the composition to mammalian skin. The composition and method reduces skin redness, flushing, pimples, pustules, and skin bumps associated with rosacea.

Description

COMPOSITION AND METHOD FOR TREATING ROSACEA

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. provisional patent application No.

60/975,558, filed September 27, 2007, incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to a method and to cosmetic and dermatological compositions useful in the treatment of rosacea. More particularly, the present invention relates to a method of treating rosacea, and to compositions having an enhanced ability to improve the appearance and condition of skin exhibiting the symptoms of rosacea. The compositions comprise a hydroxycinnamic acid and/or a methoxycinnamic acid in a suitable carrier for topical application to mammalian skin. The hydroxycinnamic acid and methoxycinnamic acid can be incorporated into various cosmetic formulations, for example, skin lotions, creams, body rinses, bath gels, skin-cleansing agents, skin-coloring compositions, foundation liquids and powders (compressed or loose), topical medicaments, and skin- treatment products.

BACKGROUND OF THE INVENTION

[0003] Rosacea is a common, but often misunderstood, skin disease that affects over

45 million people worldwide. Rosacea can cause redness and pimples on the nose, cheeks, chin and forehead of an individual, and also can cause burning and soreness in the eyes and eyelids. Rosacea often is termed "adult acne" because outbreaks, or flare-ups, can resemble acne. Rosacea therefore is embarrassing, and left untreated, can worsen. Rosacea sufferers also often report periods of depression stemming from cosmetic disfigurement, painful burning sensations, and decreases in quality of life.

[0004] The exact cause of rosacea is unknown. One causal theory is oversensitive blood vessels in the face. Because rosacea causes increased skin warmth, bacteria can grow, causing the pimples and bumps. Tiny mites (Demodex folliculorum) that normally live on our skin may also play a role in the rosacea. Individuals suffering from rosacea have more of these mites on their faces than individuals free of the disease. There also can be a relationship between rosacea and Helicobacter pylori bacteria, which causes an infection in the gastrointestinal tract, although studies are unclear. [0005] Rosacea tends to affect people having fair skin or that blush easily, e.g., individuals of northwestern European descent, and appears to run in families. Rosacea is not caused by alcohol abuse, as originally thought. However, drinking alcohol can cause rosacea symptoms to flare. Rosacea also flares when an event causes the blood vessels in the face to expand, i.e., dilate, which causes redness. Common triggers for rosacea flaring include exercise, sun and wind exposure, hot weather, stress, caffeine, spicy foods, alcohol, and hot baths. Swings in temperature from hot to cold, or cold to hot, also can cause a flare of rosacea.

[0006] Individuals may notice that their skin has become very sensitive, or that they blush easily, before they notice other symptoms of rosacea. Facial products, for example, may burn their skin. As rosacea develops, redness on the cheeks lingers, like a slight sunburn. This redness and other symptoms of rosacea are intermittent, punctuated by periods of exacerbation and relative remission.

[0007] The main symptoms of rosacea include:

[0008] (a) facial redness/flushing. Triggers, such as sun exposure or alcohol, stimulate increased blood flow, which causes blood vessels to expand and facial redness to appear. In women, the redness usually appears on the cheeks, nose, chin, and forehead. The redness may appear in a "butterfly" pattern across the cheeks and nose. Facial redness in men typically appears on the nose, although symptoms can appear on other areas on the face. In some cases, redness also can occur on the neck and upper chest.

[0009] (b) pimples on the face. Small pimples may occur on the red areas of skin or on the edges. These pimples are red, round bumps in the skin, and are different from acne pimples, which have blackheads or whiteheads.

[0010] (c) red lines on the face (telangiectasia). These small, thin, red lines, which are tiny blood vessels having a spiderweb appearance, usually appear on the cheeks.

[0011] (d) swollen bumps on the nose and cheeks. Without treatment, rosacea can cause knobby bumps on the nose and cheeks that can multiply. In severe cases, mostly in men, the nose appears enlarged, bulbous, waxy, and red, which is a condition called rhinophyma.

[0012] (e) eye irritation. Symptoms include redness, dryness, burning, crusted mucus, tearing, a gritty sensation like that of sand in the eye, pinkeye (conjunctivitis), and swelling in the eyelid. The eyes may not tolerate contact lenses, and styes can develop. In some cases, vision may be blurry, but vision is damaged only in severe cases. About one-half of individuals suffering from rosacea have some eye irritation or symptoms. If untreated, rosacea can lead to serious eye problems.

[0013] Rosacea develops in phases. The first signs may be a tendency to readily blush, wherein rosy cheeks or patches of red appear on the face. Facial skin also may be more sensitive and may react to skin products, such as lotions or soaps. Some individuals notice eye irritation before any skin symptoms are noted. As rosacea progresses, facial redness comes and goes on the cheeks, forehead, or chin. Facial flushing occurs when there is a sudden increase of blood flowing through the blood vessels under the skin. This causes the blood vessels to dilate, and results in skin redness. In time, ongoing dilation can cause blood vessels to enlarge and appear as small red lines on the skin. Tiny pimples can appear on and around the area of redness. As flare-ups continue, the redness increases, and flare-ups occur more often. Later, if the rosacea is untreated, the redness and red lines can become permanent.

[0014] Rosacea can be successfully treated symptomatically, but no cure exists for rosacea. If untreated, rosacea symptoms can worsen, recur more often, and eventually become permanent. For example, rosacea can lead to rhinophyma, in which long-term (chronic) inflammation causes the nose to appear enlarged and bulbous, red, and with thick bumps. This condition is attributed to the oil-producing (sebaceous) glands and the tissues of the nose enlarging. Rhinophyma is more common in men than women, and often takes years to develop.

[0015] Drugs and other treatments can be prescribed for treating rosacea. Treatment can help control rosacea symptoms and prevent the condition from worsening. For example, antibiotic creams or pills can be used to treat redness and pimples. Antibiotic pills also can help treat eye problems. Typically, weeks of treatment are required before improvement is observed. Stronger drugs can be used when antibiotics do not control the rosacea. Examples include isotretinoin (Accutane) or tretinoin cream (Retin-A). Surgery and other treatments also can improve skin appearance in cases of advanced rosacea. Such treatments include dermabrasion, cyosurgery, and laser surgery.

[0016] Individuals can suffer from one or more forms of rosacea. Treatment for the four main forms of rosacea vary depending on the symptoms. The four main forms of rosacea are:

[0017] (a) Erythematotelangiectatic. Symptoms include flushing and often thin, red lines (telangiectasias) on the face. Some individuals report stinging or burning of the face. Treatment can include oral antibiotics, because the skin may be too sensitive for use of ointments on the face. In mild cases, a gentle anti-inflammatory product and sunscreen in the morning can be used. If medication does not clear up the thin, red lines, which are tiny blood vessels, a form of laser surgery, i.e., pulsed dye laser therapy, may help.

[0018] (b) Papulopustular. Symptoms include small pimples or pustules. Facial flushing and tiny, red lines on the cheeks also can appear. Ointments for the face and/or antibiotic medication can be prescribed. The skin tends to be less sensitive with this form of rosacea.

[0019] (c) Phymatous. Symptoms include thick, bumpy skin and large pores. The most common type affects the nose i.e.. rhinophyma. Other types affect the chin, forehead, ears, and eyelids. Flushing, pimples, and visible blood veins also are symptoms. Isotretinoin may be prescribed for phymatous rosacea in its early stages. Surgery or laser resurfacing can reshape the nose in severe cases of rhinophyma.

[0020] (d) Ocular. Symptoms include red, dry, and irritated eyes. Individuals may feel like something is in the eye. The eyelids can swell or feel dry and flaky, and in severe cases, the individual can feel pain or have blurred vision. Ocular complications occur in a small but significant number of rosacea patients; these include blepharitis, chalazion, conjunctivitis, and keratinitis. Progressive keratinitis can lead to scarring and blindness. Artificial tears can be used for dry eyes, and ointments work well for mild cases. Antibiotic pills also can be prescribed.

[0021] Treating rosacea varies from patient to patient depending on severity and subtypes of the disease. It is important to recognize the early signs of rosacea for an accurate diagnosis and proper therapy and counseling. Dermatologists are recommended to take a subtype-directed approach to treating rosacea patients. Trigger avoidance is an integral part of the rosacea treatment, and can help reduce the onset of rosacea, but alone normally will not cause remission for all but mild cases. With treatment, rosacea symptoms usually improve in 2 to 4 weeks. The best results typically are seen after about two months of treatment.

[0022] When suffering from rosacea, it is important to adhere to a gentle skin cleansing regimen using non-irritating cleansers. Protection from the sun also is important, and daily use of a sunscreen of at least SPF 15 containing a physical blocker, such as zinc oxide or titanium dioxide, is advised although chemical sunscreens, if non-irritating to the skin, also can be used. Oral tetracycline antibiotics (tetracycline, doxycycline, minocycline) and topical antibiotics, such as metronidazole, usually are the first line of defense prescribed by doctors to relieve papules, pustules, inflammation, and redness. Oral antibiotics also can help to relieve symptoms of ocular rosacea. However, the antibiotic must be continued for life at the lowest dose that suppresses the condition, because rosacea recurs when therapy is interrupted.

[0023] In addition to the undesirability of a constant use of antibiotics in general, a disadvantage of such treatments is the possible side effects associated with long-term use of oral antibiotics, such as nausea, gastrointestinal upset, phototoxicity, enhanced susceptibility to yeast infection, and interactions with other medications. Oral antibiotics also may reduce the effectiveness of oral contraceptives. High-potency topical corticosteroid preparations may induce or aggravate pre-existing rosacea, and should not be used for long periods of time on the face. Instead, topical metronidazole sometimes is prescribed for reducing skin redness and the number of pimples on the face of patients with rosacea. If papules and pustules persist, isotretinoin can be prescribed. Isotretinoin has many side effects and is normally used to treat severe acne, but in low dosages is effective against papulopustular and phymatous rosacea.

[0024J The treatment of flushing and blushing using clonidine, a centrally acting α-2 agonist, has been attempted, but there is no evidence that this of any benefit. The same is true of the beta-blockers nadolol and propanolol. There also is no evidence that antihistamines are of any benefit in treating rosacea.

[0025] Dermatological vascular laser or Intense Pulsed Light machines offer one of the best treatments for rosacea, in particular the erythema (redness) of the skin. These treatments use light to penetrate the epidermis to target the capillaries in the dermis layer of the skin. The light is absorbed by oxyhemoglobin which heats causing the capillary walls to heat to 70⁰C, damaging them, and causing them to be absorbed by the body's natural defense mechanism.

[0026] Carbon dioxide lasers can be used to remove excess tissue caused by phymatous rosacea. Carbon dioxide lasers emit a wavelength that is absorbed directly by the skin. The laser beam can be focused into a thin beam and used as a scalpel or defocused and used to vaporize tissue. Low level light therapies have also been used to treat rosacea.

[0027] To date, all methods of treating rosacea have demonstrated disadvantages.

Accordingly, a need remains in the art for skin care compositions and methods capable of treating the symptoms of rosacea, and improving the condition and appearance of the skin exhibiting the signs of rosacea. The compositions and method of the present invention meet this need by effectively treating rosacea symptoms with a hydroxycinnamic acid and/or a methoxycinnamic acid, via topical application.

SUMMARY OF THE INVENTION

[0028J The present invention is directed to a cosmetic or dermatological composition used in a method of treating and inhibiting rosacea symptoms. More particularly, the present invention is directed to a composition that demonstrates an ability to treat rosacea symptoms, and that improves the appearance and condition of skin exhibiting signs of rosacea. The compositions maintain and improve skin tone, and reduce the incidence of rosacea symptoms, such as redness and telangiectasias. By controlling redness and telangiectasias, it is expected that the incidence of pimples and pustules associated with rosacea also will be reduced. [0029] In accordance with the present invention, a hydroxycinnamic acid or a methoxycinnamic acid, i.e., collectively termed an HCA, is used in a method of treating rosacea. Typically, an HCA is incorporated into a cosmetic or dermatological composition for topical application to skin exhibiting signs of rosacea. In one embodiment, the HCA is dissolved in an organic compound having one or more hydroxy groups, a silicone fluid, or a mixture thereof. The organic compound having a hydroxy group can be an organic solvent or a surfactant, e.g., a polyethylene glycol (PEG) or a monoCi^alkyl ether of an ethylene glycol oligomer or a propylene glycol oligomer.

[0030] Therefore, one embodiment of the present invention is to provide a method of treating rosacea symptoms comprising contacting skin of a mammal in need of such treatment with a sufficient amount of a hydroxycinnamic acid, a methoxycinnamic acid, or mixtures thereof, to maintain or improve at least the visible indicia of rosacea. [0031] Another embodiment of the present invention is to provide a composition comprising about 0.01% to about 30%, by weight, of an HCA, preferably dissolved in a solvent that enhances delivery to and availability of an HCA at an active skin site. Such solvents include, but are not limited to, an organic compound having one or more hydroxy group, a silicone fluid, or a mixture thereof. The composition is applied directly to the skin, and is in the form of a cosmetic or dermatological formulation, for example, an oil-in- water emulsion, a water-in-oil emulsion, or a gel.

[0032] The amount of HCA necessary to treat rosacea symptoms is not fixed per se, and is dependent upon the identity of HCA employed, the amount and type of any additional ingredients used, skin type, and the severity and extent of the rosacea. [0033] Another embodiment of the present invention is to provide a method of treating rosacea symptoms in humans comprising applying a composition comprising an

HCA, preferably dissolved in an organic compound having one or more hydroxy group, a silicone fluid, or a mixture thereof, to a skin surface of a mammal in need of such treatment.

The method is capable of improving visible indicia of rosacea, e.g. reduces telangiectasias, and maintaining a normal, healthful skin appearance and condition. The method and composition also help prevent and reduce the occurrence of pimples and pustules associated with rosacea.

[0034] In accordance with the present invention, an HCA is incorporated into a composition suitable for application to the skin of a mammal. The composition can further contain additional formulation ingredients for an efficient and efficacious application of the

HCA to the skin.

[0035] Another embodiment of the present invention is to provide a method of treating rosacea symptoms comprising a topical application to skin exhibiting the signs of rosacea of a composition containing an HCA having skin-beneficial properties, including maintaining a healthy skin and reducing visual signs of rosacea.

[0036] Still another embodiment of the present invention is to provide a method of treating rosacea symptoms comprising a topical application of an HCA having skin-beneficial properties at least one time per 24-hour period, and/or in accordance with a treatment regimen of at least four weeks in duration.

[0037] The topically applied compositions include skin lotions, creams, body rinses, skin-cleansing agents, skin-coloring compositions, foundation liquids and powders

(compressed or loose), topical medicaments, and skin-treatment products.

[0038] Yet another embodiment of the present invention is to provide a composition containing an HCA dissolved in an organic compound having one or more hydroxy group and/or a silicone fluid, and use of the composition as a skin-care product, a topical drug product, or a cosmetic product to treat visual indicia of rosacea.

[0039] These and other aspects and novel features of the present invention will become apparent from the following detailed description of the preferred embodiments.

DETAILED DESCRIPTION QF THE PREFERRED EMBODIMENT

[0040] Rosacea is a common chronic dermatosis. Individuals suffering from rosacea suffer from embarrassment and depression due to the cosmetic disfigurement and burning sensations associated with the condition. Therefore, a reduction in the visual indicia of rosacea symptoms, e.g., skin redness, red lines, pimples, and pustules, occupies great consumer emphasis. As discussed above, various treatments are available, but each has a distinct disadvantage.

[0041] Compositions of the present invention maintain and improve the appearance and condition of the skin of rosacea sufferers, and reduce the effects of rosacea on the skin, such as redness, telangiectasias, and other visual indicia of rosacea. For example, the present cosmetic compositions reduce the appearance of redness, pimples, and telangiectasias, particularly, but not limited to, on the face area.

|0042] The present invention also is directed to providing compositions that overcome problems associated with prior compositions and methods used to treat rosacea symptoms. In particular, the present compositions contain an HCA and maintain and improve skin tone and appearance.

[0043] As used herein, the terms "maintain" and "inhibit" means that a visual indicia of rosacea does not worsen over time, e.g., the incidence of redness, telangiectasias, and/or pimples does not increase over time, but rather remains relatively constant. The terms

"improve" and "treat" mean that a visual indicia of rosacea is ameliorated, palliated, or reversed after treatment in accordance with the present invention.

[0044] Symptoms and signs of rosacea treated by the present composition and method include, but are not limited to, visible indicia attributed to rosacea. Visual symptoms that result from rosacea include, but are not limited to, skin flushing and redness, pustules, pimples, and telangiectasias.

[0045] In accordance with the present invention, the visual indicia of rosacea are significantly reduced by treatment with an HCA. In particular, an 8-week study conducted on humans of differing ethnicities demonstrated the effects of hydroxycinnamic acid (HCA) in treating the symptoms of rosacea. HCA therefore is highly efficacious in its ability to improve the skin condition of individuals suffering from rosacea by reversing the visual indicia of rosacea, both in terms of skin feel and appearance.

[0046] More particularly, p-hydroxycinnamic acid is a phenolic cinnamic acid derivative that inhibits the development of cancer, and is found in various plants such as tomatoes, green peppers, carrots, strawberries, and pineapples, as well as herbal plants, like basil and turmeric. HCAs are nontoxic and nonirritating and are potent tyrosinase inhibitors.

Some HCAs, like p-hydroxycinnamic acid (p-HCA), can be found in fruits and vegetables, and presently are being used in the food industry as antioxidants. p-Hydroxycinnamic acid is activated during digestion and interferes with the development of cancer-causing nitrosamines. p-Hydroxycinnamic acid also is used in the cosmetic industry as a bacteriostat. [0047] Irrespective of these positive attributes, no commercial cosmetic composition including an HCA in general, or p-HCA in particular, has been introduced. The reasons for this lack of commercial products containing an HCA are two-fold. First, HCAs have poor skin permeability. Second, HCAs are highly insoluble in solvents and carriers typically used in skin care and dermatological compositions. A preferred embodiment of the present invention incorporates an HCA into a cosmetic composition and permits the use of an HCA in treating the symptoms and indicia of rosacea.

[0048] A composition utilized in the present invention typically contains about 0.01% to about 30%, by weight, of one or more HCA. In other embodiments, the composition contains about 0.1% to about 20%, or about 0.5% to about 15%, by weight, of one or more HCA, and all ranges and subranges therein, for example about 0.2, 0.4, 0.6, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15%, by weight, of one or more HCA. The composition can be used as is, diluted, or admixed with other composition ingredients known in the cosmetic and dermatologic arts to provide an efficacious and esthetic composition for topical application to the skin.

[0049] The HCA can be, but is not limited to, 2-, 3-, or 4-hydroxycinnamic acids;

2,3-, 2,4-, or 3-4-dihydroxycinnamic acid; 2-, 3-, or 4-methoxycinnamic acid; 3-hydroxy-4- methoxycinnamic acid; 4-hydroxy-3-methoxycinnamic acid; or mixtures thereof. As used herein, an HCA also can be ferulic acid, caffeic acid, cinnamic acid, gallic acid, rosmarinic acid, vanillic acid, and mixtures thereof. In some embodiments, the HCA comprises 2-, 3-, or 4-hydroxycinnamic acid. An especially useful HCA is 4-hydroxycinnamic acid. [0050] For the sake of brevity, the following disclosure is particularly directed to 4- hydroxycinnamic acid, also known as p-hydroxycinnamic acid or p-coumaric acid, and referred to herein as "p-HCA." It should be understood that other HCAs can be substituted for p-HCA in a composition and method of the present invention.

[0051] The compositions and methods of the present invention are useful in treating a variety of symptoms and indicia related to rosacea, for example, skin redness, pimples, swollen bumps, and telangiectasias. The present invention is directed to a method of treating skin comprising topically applying an HCA to the skin of an individual suffering from rosacea, typically wherein the HCA is present in a composition comprising an HCA dissolved dispersed, or suspended in a suitable carrier, for example, a silicone fluid or a hydroxy- containing compound, e.g., a PEG or a monoCi^alkyl ether of an ethylene glycol oligomer or a propylene glycol oligomer, to skin to help maintain a normal, healthy skin appearance or improve the appearance and condition of the skin of an individual suffering from rosacea. [0052] In one embodiment, an HCA is dissolved in an organic compound having one or more hydroxy group, a silicone fluid, or a mixture thereof. The organic compound containing one or more hydroxy group can be a surfactant or an organic solvent. The compound containing one or more hydroxy group can contain one to six hydroxy groups, and typically contains one to three hydroxy groups. The HCA also can be dissolved or dispersed in other solvents and surfactants typically used in cosmetic and dermatologic compositions. [0053] In one embodiment, the HCA is dissolved in a

ether of an ethylene glycol oligomer or a propylene glycol oligomer, also termed herein as a "monoCi_₄alkyl ether." In other embodiments, the HCA is dissolved in a C₂-C₄ alcohol, a C₃- C₅ glycol, a polyethylene glycol (e.g., PEG-4), a polypropylene glycol, a triol, a polyol, an ethoxylated glycerin, an ethylene oxide-propylene oxide block copolymer, or mixtures thereof. Nonlimiting examples of useful compounds include propylene glycol, butylene glycol, pentylene glycol, glycereth-7 through glycereth-31 , PEG-4 through PEG-800, PPG-3 through PPG-69, ethanol, isopropyl alcohol, n-propanol, n-butanol, sec-butanol, t-butyl alcohol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, hexylene glycol, 1 ,2,6-hexanetriol, sorbitol, and mixtures thereof.

[0054] Examples of preferred compounds having one or more hydroxy group include, but are not limited to, ethoxydiglycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, PEG-4 through PEG-20, PPG-3 through PPG-15, an ethylene oxide-propylene oxide block copolymer containing about 4 to about 20 total ethylene oxide and propylene oxide units. Nonlimiting examples include PEG-4, PEG-6, PEG-8, PEG-9, PEG-10, PEG-12, PEG-16, PEG-18, PEG-20, PPG-3, PPG-9, PPG-12, PPG-15, poloxamer 101, and mixtures thereof.

[0055] Useful surfactants having one or more hydroxy groups include nonionic surfactants, not limited to, ethoxylated octyl phenols, ethoxylated nonyl phenols, ethoxylated linear C₈-C₂₂ alcohols, propoxylated linear C₈-C₂₂ alcohols, ethoxylated and propoxylated Q- C₂₂ alcohols, polyethylene glycol ethers of sorbitol, or mixtures thereof. [0056] Useful silicone fluids include linear and cyclic, volatile and nonvolatile, dimethyl siloxane fluids, including siloxane fluids having phenyl substituents. Useful silicone fluids are disclosed in U.S. Patent No. 5,456,863, incorporated herein by reference. [0057] An HCA solution or dispersion can be applied directly to skin. In this case, the amount of HCA in the solution or dispersion typically is about 0.01% to about 10%, by weight of the solution or dispersion. The HCA solution or dispersion also can be diluted with a solvent or other carrier prior to application to the skin. The diluting solvent can be the same or different from the organic compound used to dissolve or disperse the HCA. In preferred embodiments, the HCA is stabilized to permit penetration of the skin surface and treating of the skin, and particularly skin exhibiting the symptoms of rosacea.

[0058] The HCA solution or dispersion can be formulated into various product forms, such as emulsions or gels, by the addition of formulation ingredients to the HCA, or addition of the HCA to the formulation ingredients. Nonlimiting formulation ingredients and product forms are discussed below, and do not adversely affect the ability of the HCA to treat aging skin. The topical, cosmetic or pharmaceutical compositions can be in any convenient form, such as a clear liquid, lotion, cream, gel, mask, spray, cleanser, or shower gel. In addition, the HCA solution or dispersion also can be added to already formulated products. For example, the HCA solution or dispersion can be added to a skin lotion that has already been made to provide added benefits from such lotion product.

[0059] In a preferred embodiment, HCA is dissolved in an organic compound having one or more hydroxy group and/or a silicone fluid, like a PEG or a monoCi-₄alkyl ether of an ethylene glycol oligomer or a propylene glycol oligomer. As discussed below, dissolving the HCA in a suitable hydroxy-containing compound improves penetration of the HCA through the skin surface and facilitates the treatment of skin exhibiting the signs of rosacea, which improves the symptoms and indicia of rosacea to a degree that previously could not be attained.

[0060] A monoCi-₄alkyl ether of an ethylene glycol oligomer or a propylene glycol oligomer used to dissolve HCA has a general formula:

R² _R2

R¹ -O-f CH₂-CH-O -V-H or R^x-O-f CH-CH₂-O -V H

wherein R¹ is R² is hydrogen or methyl, and n is 2 or 3. For example, R¹ is methyl, ethyl, isopropyl, n-propyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

[0061] Nonlimiting examples of a monoCi^alkyl ether of an ethylene glycol or propylene glycol oligomer include, but are not limited to, ethoxydiglycol, methoxydiglycol, butoxydiglycol, methoxytriglycol, ethoxytriglycol, and mixtures thereof. Preferred monoethers include ethoxydiglycol and methoxydiglycol. In a more preferred embodiment, the monoether comprises ethoxydiglycol.

[0062] In other preferred embodiments, the organic compound having one or more hydroxy group comprises diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol. PEG-4 through PEG-20, PPG-3 through PPG-15, an ethylene oxide- propylene oxide block copolymer containing about 4 to about 20 total ethylene oxide and propylene oxide units, and mixtures thereof.

[0063] As previously stated, an HCA solution or dispersion can be applied as is, after dilution, or after incorporation into a cosmetic or dermatological formulation. The final composition also can contain an optional second active agent known as useful in the treatment of rosacea. Useful second active agents useful in the treatment of rosacea include, but are not limited to, antibiotics, isotretinoin, tretinoin, antiinflammatory compounds, sunscreen actives, and mixtures thereof.

[0064] Specifically, second active agents useful in the treatment of rosacea include, but are not limited to, steroidal antiinflammatory agent of the hydrocortisone-type and the like; a nonsteroidal antiinflammatory agent selected from the group consisting of acetylsalicylic acid, acetaminophen, naproxen, and fenamic acid derivatives, such as the sodium salt; antiinflammatory agents, such as alpha-bisabolol, beta-glycyrrhetinic acid, allantoin, aloe extract, rosmarinic acid, azulene or a derivative thereof, asiaticoside, sericoside, ruscogenin, escin, escolin, quercetin, rutin, betulinic acid or a derivative thereof, catechin or a derivative thereof; an antioxidant such as a polyphenol, a carotenoid, and a flavonoid, for example, hesperidin, diosmin, mangiferin, mangostin, cyanidin, astaxanthin, xanthophyll, lycopene, carotene, resveratrol, tetrahydrocurcumin, rosmarinic acid, ellagic acid, hypericin, chlorogenic acid, oleuropein, lipoic acid, glutathione-oxidized, cystine, N- acetyl-cystine, glutathione-reduced, cystein, and N-acetyl-cysteine; collagen and fibrin boosting compounds, such as cosamine, N-acetyl-glucosamine, chondroitin, algae extracts, chitosan, niacinamide, niacinamide derivatives, glutathione, carnosine, vitamin C, vitamin E, vitamin A, Coenzyme QlO, dimethylaminoethanol, ascorbic acid, ascorbic acid derivatives, glucosamine ascorbate, arginine ascorbate, lysine ascorbate, glutathione ascorbate, nicotinamide ascorbate, niacin ascorbate, allantoin ascorbate, creatine ascorbate, creatinine ascorbate, chondroitin ascorbate, chitosan ascorbate, DNA ascorbate, carnosine ascorbate, tocotrienol, lutein, niacinamide lipoate, glutathione, andrographolide, carnosine, Potentilla erecta extract, grapeseed extract, pycnogenol (Pine Bark extract), copper nucleotide, zinc nucleotide, manganese nucleotide, copper glucoside, zinc glucoside, manganese glucoside, and mixtures thereof.

[0065] Preferred second active agents useful in the treatment of rosacea include erythromycin, clindamycin, tetracycline, metronidazole, azelaic acid, adapalene, isotretinoin, sulfacetamide-sulfur, doxycycline, minocycline, sunscreens, and mixtures thereof. [0066] Because symptoms and indicia attributed to rosacea are very similar to symptoms and indicia related to sunburn, the compositions and methods of the present invention also are useful for treating the skin for sunburn.

[0067] An HCA-containing composition is useful in personal care, cosmetic, and pharmaceutical compositions. The compositions provide an effective delivery of an HCA to treat the skin of an individual suffering from rosacea and reduce or eliminate the indicia of rosacea, e.g., skin redness and telangiectasias. The resulting compositions for treating skin exhibiting signs of rosacea can be formulated with other topically-applied active compounds, in addition to or in lieu of an optional second active useful in the treatment of rosacea, to achieve both a reduction in the symptoms of rosacea and a second cosmetic or therapeutic effect different from treating rosacea.

[0068] In accordance with an important feature of the present invention, a topically- applied compound for providing a second cosmetic or therapeutic effect can be any of a wide variety of compounds, either water soluble or oil soluble.

[0069] Additional topically-applied active compounds, such as hormones, analgesics, anesthetics, sun screens, skin whiteners, antiacne agents, antibacterial agents, antifungal agents, botanical extracts, pharmaceuticals, minerals, plant extracts, concentrates of plant extracts, exfoliants, emollients, moisturizers, skin protectants, humectants, silicones, skin soothing ingredients, colorants, perfumes, and like can be added to the composition. The quantities of such active compounds present in the composition are sufficient to perform their intended function, without adversely affecting the rosacea-treating benefits of the composition.

[0070] More particularly, such a topically applied active compound can be one of, or a mixture of, a cosmetic compound, a medicinally active compound, a compound used in cosmetics or personal care, or any other compound that is useful upon topical application to the skin. Such topically active agents include, but are not limited to, skin-care compounds, plant extracts, antioxidants, insect repellants, counterirritants, vitamins, steroids, antibacterial compounds, antifungal compounds, antiinflammatory compounds, topical anesthetics, sunscreens, optical brighteners, and other cosmetic and medicinal topically effective compounds.

[0071] For example, a skin conditioner can be the topically applied compound. Skin conditioning agents include, but are not limited to, humectants, such a fructose, glucose, glycerin, propylene glycol, glycereth-26, mannitol, pyrrolidone carboxylic acid, hydrolyzed lecithin, coco-betaine, cysteine hydrochloride, glucamine, sodium gluconate, potassium aspartate, oleyl betaine, thiamine hydrochloride, sodium laureth sulfate, sodium hyaluronate, hydrolyzed proteins, hydrolyzed keratin, amino acids, amine oxides, water-soluble derivatives of vitamins A, E, and D, selenium and derivatives thereof, amino-functional silicones, ethoxylated glycerin, alpha-hydroxy acids and salts thereof, fatty oil derivatives, such as PEG-24 hydrogenated lanolin, beta-hydroxy acids and salts thereof (e.g., glycolic acid, lactic acid, and salicylic acid), and mixtures thereof. Numerous other skin conditioners are listed in the CTFA Cosmetic Ingredient Handbook, First Ed., J. Nikotakis, ed., The Cosmetic, Toiletry and Fragrance Association (1988), (hereafter CTFA Handbook), pages 79- 84, incorporated herein by reference.

[0072] The skin conditioner also can be a water-insoluble ester having at least 10 carbon atoms, and preferably 10 to about 32 carbon atoms. Suitable esters include those comprising an aliphatic alcohol having about eight to about twenty carbon atoms and an aliphatic or aromatic carboxylic acid including from two to about twelve carbon atoms, or conversely, an aliphatic alcohol having two to about twelve carbon atoms with an aliphatic or aromatic carboxylic acid including about eight to about twenty carbon atoms. The ester is either straight-chained or branched. Suitable esters, therefore, include, for example, but are not limited to:

[0073] (a) aliphatic monohydric alcohol esters, including, but not limited to: myristyl propionate, isopropyl isostearate, isopropyl myristate, isopropyl palmitate, cetyl acetate, cetyl propionate, cetyl stearate, isodecyl neopentanoate, cetyl octanoate, isocetyl stearate;

[0074] (b) aliphatic di- and tri-esters of polycarboxylic acid, including, but not limited to: diisopropyl adipate, diisostearyl fumarate, dioctyl adipate, and triisostearyl citrate; [0075] (c) aliphatic polyhydric alcohol esters, including, but not limited to: propylene glycol dipelargonate;

[0076] (d) aliphatic esters of aromatic acids, including, but not limited to: C]₂-Ci₅ alcohol esters of benzoic acid, octyl salicylate, sucrose benzoate, and dioctyl phthalate. [0077] Numerous other esters are listed in the CTFA Handbook, at pages 24 through

26, incorporated herein by reference.

[0078] The topically applied compound also can be retinoic acid or a retinol derivative.

[0079] The topically applied compound further can be an antioxidant or an optical brightener, like a distyrylbiphenyl derivative, stilbene or a stilbene derivative, a pyralozine derivative, or a coumarin derivative. Optical brighteners useful as the topically applied compound can be any compound capable of absorbing an invisible UV portion of the daylight spectrum, and converting this energy into the longer visible wavelength portion of the spectrum. The optical brightener is colorless on the substrate, and does not absorb energy in the visible part of the spectrum. The optical brightener typically is a derivative of stilbene or 4,4'-diaminostilbene, biphenyl, a 5-membered heterocycle, e.g., triazole, oxazole, or imidazole, or a 6-membered heterocycle, e.g., a coumarin, a naphthalamide, or an s-triazine. [0080] The optical brighteners are available under a variety of tradenames, such as

TINOPAL*¹, LEUCOPHOR^®, and CALCOFLUOR^®. Specific fluorescent compounds include, but are not limited to, TINOPAL* 5BM, CALCOFLUOR^® CG, and LEUCOPHOR^® BSB.

[0081] In addition, other compounds can be included in a present composition as the topically active compound in an amount sufficient to perform their intended function. For example, sunscreen compounds such as benzophenone-3, tannic acid, uric acids, quinine salts, dihydroxy naphtholic acid, an anthranilate, p-aminobenzoic acid, phenylbenzimidazole sulfonic acid, PEG-25, or p-aminobenzoic acid can be used as the topically applied compound. Further, sunscreen compounds such as dioxybenzone, ethyl 4- [bis(hydroxypropyl)] aminobenzoate, glyceryl aminobenzoate, homosalate, methyl anthranilate, octocrylene, octyl methoxycinnamate, octyl salicylate, oxybenzone, padimate O, red petrolatum, titanium dioxide, 4-menthylbenzylidene camphor, benzophenone-1, benzophenone-2, benzophenone-6, benzophenone-12, isopropyl dibenzoyl methane, butyl methoxydibenzoylmethane, zotocrylene, or zinc oxide can be used as the topically applied compound. Other sunscreen compounds are listed in CTFA Handbook, pages 86 and 87, incorporated herein by reference.

[0082] Similarly, topically applied drugs, like antifungal compounds, antibacterial compounds, antiinflammatory compounds, topical anesthetics, skin rash, skin disease, and dermatitis medications, and antiitch and irritation-reducing compounds can be used as the active agent in the compositions of the present invention. For example, analgesics such as benzocaine, dyclonine hydrochloride, aloe vera, and the like; anesthetics such as butamben picrate, lidocaine hydrochloride, xylocaine, and the like; antibacterial s and antiseptics, such as povidone-iodine, polymyxin b sulfate-bacitracin, zinc -neomycin sulfate-hydrocortisone, chloramphenicol, ethylbenzethonium chloride, erythromycin, and the like; antiparasitics, such as lindane; essentially all dermatologicals, like acne preparations, such as benzoyl peroxide, erythromycin benzoyl peroxide, clindamycin phosphate, 5,7-dichloro-8-hydroxyquinoline, and the like; antiinflammatory agents, such as alclometasone dipropionate, betamethasone valerate, and the like; burn relief ointments, such as o-amino-p-toluenesulfonamide monoacetate, and the like; depigmenting agents, such as monobenzone; dermatitis relief agents, such as the active steroid amcinonide, diflorasone diacetate, hydrocortisone, and the like; emollients and moisturizers, such as mineral oil, PEG-4 dilaurate, lanolin oil. petrolatum, mineral wax, and the like; fungicides, such as butocouazole nitrate, haloprogin, clotrimazole, and the like; herpes treatment drugs, such as O-[(2-hydroxymethyl)- methyljguanine; pruritic medications, such as alclometasone dipropionate, betamethasone valerate, isopropyl myristate MSD, and the like; psoriasis, seborrhea, and scabicide agents, such as anthralin, methoxsalen, coal tar, and the like; steroids, such as 2-(aeetyloxy)-9-fluoro- r,2',3',4'-tetrahydro-l l-hydroxypregna-l ,4-dieno-[16,17-b]naphthalene-3,20-dione and 21- chloro-9-fluoro- 1 ',2',3 ',4'-tetrahydro- 1 1 b-hydroxypregna- 1 ,4-dieno-[ 16, 17-b]naphthalene- 3,20-dione. Any other medication capable of topical administration, like skin protectants, such as allantoin, also can be incorporated in a composition of the present invention in an amount sufficient to perform its intended function. Other topically applied compounds are listed in Remington's Pharmaceutical Sciences, 17th Ed. , Mack Publishing Co., Easton, PA (1985), pages 773-791 and pages 1054-1058 (hereinafter Remington's), incorporated herein by reference.

[0083] The topically active compound also can be a plant extract on a natural oil.

Numerous plant extracts are available from Lipo Chemicals, Inc. Paterson, New Jersey. Nonlimiting plant extracts are those obtained from alfalfa, aloe vera, amla fruit, angelica root, anise seed, apple, apricot, artichoke leaf, asparagus root, banana, barberry, barley sprout, bee pollen, beet leaf, bilberry fruit, birch leaf, bitter melon, black currant leaf, black pepper, black walnut, blueberry, blackberry, burdock, carrot, cayenne, celery seed, cherry, chickwood, cola nut, corn silk, cranberry, dandelion root, elderberry, eucalyptus leaf, flax oil powder, ginger root, gingko leaf, ginseng, goldenrod, goldenseal, grape, grapefruit, guava, hibiscus, juniper, kiwi, kudzu, lemon, licorice root, lime, malt, marigold, myrrh, olive leaf, orange fruit, orange peel, oregano, papaya fruit, papaya leaf, passion fruit, peach, pear, pine bark, plum, pomegranate, prune, raspberry, rhubarb root, rosemary leaf, sage leaf, spearmint leaf, St. John's wart, strawberry, sweet cloves, tangerine, violet herb, watercress, watermelon, willow bark, wintergreen leaf, witch hazel bark, yohimbe, and yucca root. An example of a natural oil is rice bran oil.

[0084] A composition of the present invention is prepared by dissolving the HCA in an organic compound having one or more hydroxy groups, a silicone fluid, or a mixture thereof, like a monoCi^alkyl ether. The present compositions can be admixed with other ingredients traditionally included in cosmetic, dermatological, medicinal, and other such compositions. These ingredients include, but are not limited to, dyes, fragrances, preservatives, antioxidants, detackifying agents, and similar types of compounds. The ingredients are included in the composition in an amount sufficient to perform their intended function.

[0085] The following additional ingredients typically are included in a present composition. Each of these ingredients, and any other ingredient, is present in a sufficient amount to perform its intended function, without adversely affecting the efficacy of HCA with respect to treating skin of an individual suffering from rosacea.

[0086] For example, a present composition can contain a surfactant. The surfactant can be an anionic surfactant, a cationic surfactant, a nonionic surfactant, or a compatible mixture of surfactants. The surfactant also can be an ampholytic or amphoteric surfactant, which have anionic or cationic properties depending upon the pH of the composition. [0087] Examples of anionic surfactants include, without limitation, soaps, alkyl sulfates, anionic acyl sarcosinates, methyl acyl taurates, N-acyl glutamates. acyl isethionates, alkyl phosphate esters, ethoxylated alkyl phosphate esters, alkyl sulfosuccinates, trideceth sulfates, protein condensates, mixtures of ethoxylated alkyl sulfates, and the like. Examples of anionic nonsoap surfactants include, without limitation, the alkali metal salts of an organic sulfate having an alkyl radical containing about 8 to about 22 carbon atoms and a sulfonic acid or sulfuric acid ester radical. Examples of zwitterionic surfactants include, without limitation, derivatives of aliphatic quaternary ammonium, phosphonium, and sulfonium compounds, in which the aliphatic radicals can be straight chain or branched and wherein one of the aliphatic substituents contains an anionic water-solubilizing group, e.g., carboxyl, sulfonate, sulfate, phosphate, or phosphonate. Examples of amphoteric surfactants include, without limitation, derivatives of aliphatic secondary and tertiary amines in which the aliphatic radical can be straight chain or branched and wherein one of the aliphatic substituents contains about 8 to about 18 carbon atoms and one contains an anionic water solubilizing group, e.g., carboxyl, sulfonate, sulfate, phosphate, or phosphonate. Examples of cationic surfactants include, without limitation, stearyldimethylbenzyl ammonium chloride; dodecyltrimethyl ammonium chloride; nonylbenzylethyldimethyl ammonium nitrate; and tetradecylpyridinium bromide. Nonionic surfactants include, without limitation, compounds produced by the condensation of ethylene oxide groups with an organic hydrophobic compound, which may be aliphatic or alkyl aromatic in nature, for example, the polyethylene oxide condensates of alkyl phenols.

[0088] A present composition also can contain a hydro trope. A hydrotrope is a compound that has an ability to enhance the water solubility of other compounds. Specific examples of hydrotropes include, but are not limited to, sodium cumene sulfonate, ammonium cumene sulfonate, ammonium xylene sulfonate, potassium toluene sulfonate, sodium toluene sulfonate, sodium xylene sulfonate, toluene sulfonic acid, and xylene sulfonic acid. Other useful hydrotropes include sodium polynaphthalene sulfonate, sodium polystyrene sulfonate, sodium methyl naphthalene sulfonate, sodium camphor sulfonate, and disodium succinate.

[0089] A present composition also can contain an additional organic solvent. The solvent can be a water-soluble organic compound containing one to six, and typically one to three, hydroxyl groups, e.g., alcohols, diols, triols, and polyols. Specific examples of solvents include, but are not limited to, methanol, ethanol, isopropyl alcohol, n-butanol, n- propyl alcohol, ethylene glycol, propylene glycol, glycerol, diethylene glycol, dipropylene glycol, tripropylene glycol, hexylene glycol, butylene glycol, 1 ,2,6-hexanetriol, sorbitol, PEG-4, 1,5-pentanediol, similar hydroxyl-containing compounds, and mixtures thereof. The solvent also can be water or an aprotic solvent, e.g., dimethyl sulfoxide or tetrahydrofuran. [0090J A present composition also can contain a thickening or gelling agent. A thickening or gelling agent can be, for example, a polymer that is water soluble or that generates a colloidal solution in water. A thickening or gelling agent, therefore, can be, for example, polymers or copolymers unsaturated carboxylic acids or unsaturated esters, polysaccharide derivatives, gums, colloidal silicates, polyethylene glycols (PEG) and their derivatives, polyvinylpyrrolidones and their derivatives, polyacrylamides and their derivatives, polyacrylonitriles, hydrophilic silica gels, or mixtures thereof. [0091] Specific thickening or gelling agents can be, for example, acrylic and/or methacrylic polymers or copolymers, vinylcarboxylic polymers, polyglyceryl acrylates or methacrylates, polyacrylamides derivatives, cellulose or starch derivatives, chitin derivatives, alginates, amino acids, ceramides, fatty acids, cholesterol and derivatives thereof, and other natural moisturizing compounds, hyaluronic acid and its salts, chonodroitin sulphates, xanthan, gellan, Rhamsan, karaya or guar gum, carob flour, and colloidal aluminum magnesium silicates of the montmorillonite type.

[0092] Additional thickening or gelling agents include vinylcarboxylic polymers sold under the tradename CARBOPOL^® (Goodrich), acrylic acid/ethyl acrylate copolymers, acrylic acid/stearyl methacrylate copolymers, carboxymethylcellulose, hydroxymefhylcellulose, hydroxypropylcellulose, microcrystalline cellulose, hydroxypropyl guar, colloidal hectorites, bentonites, and the like.

[0093] Other classes of optional ingredients included in a present composition can be, but not limited to, pH adjusters, chelating agents, preservatives, buffering agents, foam stabilizers, opacifiers, and similar classes of ingredients known to persons skilled in the art. Specific optional ingredients include inorganic phosphates, sulfates, and carbonates as buffering agents; EDTA and phosphates as chelating agents; and acids and bases as pH adjusters.

[0094] Nonlimiting examples of basic pH adjusters are ammonia; mono-, di-, and tri- alkyl amines; mono-, di-, and tri-alkanolamines; alkali metal and alkaline earth metal hydroxides; and mixtures thereof. Specific, nonlimiting examples of basic pH adjusters are ammonia; sodium, potassium, and lithium hydroxide; monoethanolamine; triethylamine; isopropanolamine; diethanolamine; and triethanolamine. Examples of acidic pH adjusters are the mineral acids and organic carboxylic acids. Nonlimiting examples of mineral acids are citric acid, hydrochloric acid, nitric acid, phosphoric acid, and sulfuric acid. [0095] The HCA can be incorporated into compositions designed as cosmetic basecoats and undercoats, bath capsules, bath oils, bath tablets, bath salts, bath soaps, blushers, face, body, and hand creams and lotions, cosmetic foundations, hormone creams and lotions, leg and body paints, makeup bases, makeup fixatives, makeup products, moisturizing creams and lotions, night creams and lotions, paste masks, skin care products, skin fresheners, skin lighteners, tonics, dressings, and wrinkle smoothing creams and lotions. [0096] In particular embodiments, the HCA can be incorporated into lotions; makeup preparations, like makeup foundations; skin care preparations, like hand lotions, vanishing creams, night creams, sunscreens, body lotions, facial creams, clay masks, moisturizing lotions, makeup removers, antiacne preparations, antiaging preparations, and sebum control; analgesic and cortisonal steroid creams and preparations; insect repellants; and facial masks and revitalizers. The compositions also can be incorporated into plasters, bandages, dressings, gauze pads, and similar articles.

[0097] The final composition can be in the form of a solution, an oil-in- water emulsion, a water-in-oil emulsion, a gel, a microemulsion, a nanoemulsion, or other product form known in the skin care and dermatological arts. The HCA also can be delivered from an encapsulated or nonencapsulated delivery system, a liposome, or other vesicle or lamellar delivery system. The composition form can be, for example, a liquid form, e.g., a solution, a gelled solution, or a suspension in an aqueous or oily medium; or a semi-liquid formulation, e.g., a cream, a gel, a paste, an ointment, a salve, a liposome, an emulsion, or a microemulsion.

[0098] A composition of the present invention is topically applied to the skin as needed in order to reduce or eliminate the symptoms and indicia of rosacea to a desired degree. Typically, the composition is topically applied to the skin one to four times per day. However, application of a present composition can be more or less frequent as prescribed, required, or desired. The present compositions are applied to the skin by spraying or rubbing. The preferred route of administration is rubbing onto the skin with a soft massage to ensure intimate contact with the skin and full absorption by the skin.

[0099] To demonstrate the new and unexpected benefits provided by a composition and method of the present invention, the following tests were performed. First, to confirm in vivo activity of p-HCA, the metabolism of p-HCA in the skin was determined. In this test, human skin was homogenized in PBS-ethanolic solution, followed by dissolution of p-HCA. The solution was incubated at 37°C for 8 hours. Samples were taken after 0, 4, and 8 hours, and were centrifuged. The supernatant was filtered and analyzed by HPLC. It was found that after eight hours of incubation with skin enzymes, that only 3.6% of the p-HCA was metabolized. The amount of p-HCA that is metabolized was considered insignificant with respect to an efficacious treatment of rosacea.

[00100] Various solvents were tested for an ability to dissolve p-HCA and provide a suitable composition for topical application to efficaciously treat the skin of an individual suffering from rosacea. p-HCA was added to various solvents, then sonicated for two hours at 35⁰C until no further HCA was dissolved. The samples were cooled to room temperature (25°C) and allowed to stabilize for 15 hours. The undissolved p-HCA was allowed to settle, the supernatant liquid was filtered, and diluted with the HPLC mobile phase for assay. All samples were analyzed by HPLC on a Hypersil ODS Cl 8 column using water, methanol, glacial acetic acid (55:45: 1) as the mobile phase. The flow rate was 1 ml/min and the wavelength for detection was 270 nm. In this test, it was found that p-HCA had a relatively high solubility in PEG-4 and ethoxydiglycol at 25°C of 18.5% and 19.7%, by weight, respectively. It was further found that p-HCA had a relatively high solubility in PEG-2 (diethylene glycol), PEG-6, and PEG-8 at 25°C of 18.1%, 19.7%, and 19.7%, by weight, respectively.

[00101] Additional hydroxy-containing compounds were tested for an ability to solubilize an HCA and allow the HCA to permeate the surface of skin. In this test, solubility of HCA in the compounds was determined as described above. [00102] It was found that p-HCA had the following solubilities, in wt %: hydroethanolic solutions/gels: e.g., 30% hydroethanolic solution: 0.75%; ethanol: 14.8%; pentylene glycol: 1.75%; butylene glycol: 2.25%; glycereth-26: 7%; silicone fluid DC 193: 4.7%.

[00103] In another experiment, a 15% solution of p-HCA in PEG-4 first was prepared.

This solution was added to a skin care emulsion in a sufficient amount to provide either 0,3% or 0.9%, by weight, of p-HCA in the final composition. As a comparative example. 0.3%, by weight, of solid p-HCA was added to the same skin care emulsion. The skin care emulsion to which solid p-HCA or the p-HCA solution was added had the following formula (w/w%): 85.35 water, 0.20 methylparaben, 0.35 xanthan gum, 5.0 butylene glycol, 4.0 sesame oil, 2.50 glyceryl stearate, 0.50 PEG- 150 distearate, 1.25 neopentyl glycol, dicaprylate/dicaprate, 0.60 emulsifying wax, 0.25 imidazolidinyl urea.

[00104] The skin care emulsions containing p-HCA were applied to cadaver skin.

Skin penetration of p-HCA was studied using Franz diffusion cells, n=5 (Permegear, Bethlehem, PA). The receptor contained an isotonic phosphate buffer with 30% ethanol, and was stirred continuously at 600 rpm. Samples of dermatomed human cadaver skin (NDRA, Philadelphia) were placed on the cells and prehydrated for 1 hour prior to the experiment. One milliliter of each formulation was added to the donor compartment of each cell, which was covered tightly with PARAFlLM*. Samples (300 μl) were withdrawn from the receptor compartment every hour over 8 hours, and replaced with 300 μl of fresh receptor solution. After 8 hours, the skin was removed and cut into small pieces. The skin pieces were homogenized using a Kinematica POLYTRON^® homogenizer and centrifuged. The supernatant was filtered through 0.22 μ filters, and the p-HCA content was quantified. [00105] All samples were analyzed by HPLC on a Hypersil ODS Cl 8 column using water, methanol, glacial acetic acid (55:45:1) as the mobile phase at a flow rate of 1 ml/min and detection at 270 ran. Lag time and flux were obtained from permeation profiles and skin drug content also was recorded. It was found that PEG-4 significantly increased the deposition of p-HCA on the skin compared to a control.

[00106] More particularly, in the composition wherein solid p-HCA was added, the cumulative amount of p-HCA (μg/cm² of skin) at the end of 8 hours was 38.10 ± 3.43. The exposed area of the skin was 0.636 cm², therefore the cumulative amount of p-HCA in micrograms in the receptor at the end of 8 hours was 25.54 μg. It also was determined that the average skin content of p-HCA was 78.68 μg.

[00107] For the composition containing p-HCA dissolved in PEG-4, the cumulative amount of p-HCA (μg/cm² of skin) at the end of 8 hours was 58.80 ± 11.3. The exposed area of the skin was 0.636 cm², therefore the cumulative amount of p-HCA in micrograms in the receptor at the end of 8 hours was 37.39 μg. It also was determined that the average skin content of p-HCA was 87.27 μg.

[00108] Normalization of the amounts of p-HCA in the skin and the receptor phase was as follows:

[00109] Overall, the above data shows that a composition containing p-HCA predissolved in PEG-4 had an improved penetration through the skin and deposited more p- HCA in the skin compound than a composition wherein p-HCA is added as a solid. [00110] The following formula was tested for skin penetration: water: 28.10% (by wt); Carbopol 981 (2%): 17.0%; ethanol SDA 40b- 190: 53.0%; glycerin: 1.0%; triethanolamine 0.4%; p-hydroxycinnamic acid: 0.5%.

[00111] The method used to determine skin permeability was the Franz diffusion method disclosed above. The test results showed that the above formula deposited an amount of HCA in the skin that is four times greater than the amount transmitted through the skin, which demonstrates a targeted delivery of p-HCA to the site of melanin formation. In particular, 3.9 mcg/ml of p-HCA was found in the receptor compartment of the skin (i.e., permeated through the skin) as opposed to 16.3 mcg/ml p-HCA found within the skin. [00112] Generally, in practice of the method of the invention, the composition is topically applied to the affected skin areas in a predetermined or as-needed regimen. Generally, gradual improvement is noted with successive applications. [00113] The present composition, therefore, effectively treats the symptoms of rosacea when applied to the skin in accordance with an extended treatment regimen of at least four weeks, and preferably at least six weeks. The skin treatment can continue indefinitely because the HCA in a present composition is stable and nontoxic. One study applied p-HCA to facial skin and a VISIA study showed a reduction in skin redness associated with rosacea and sunburn.

[00114] The application of a p-HC A-containing composition twice daily for 8 weeks yielded no observable skin irritation. It is theorized, but not relied upon, that p-HCA improves the appearance of skin exhibiting the signs of rosacea because of its antioxidant and radical scavenging properties, and the ability of a present composition to penetrate the skin and position the p-HCA where the skin-beneficial effects of the p-HCA can be realized. [00115] Obviously, many modifications and variations of the invention as hereinbefore set forth can be made without departing from the spirit and scope thereof and, therefore, only such limitations should be imposed as are indicated by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A method of treating mammalian skin exhibiting symptoms of rosacea comprising contacting the skin of a mammal in need of such treatment with a sufficient amount of a hydroxycinnamic acid, a methoxycinnamic acid, or mixtures thereof, to maintain or improve at least visible indicia of rosacea.

2. A method of treating mammalian skin exhibiting symptoms of rosacea comprising contacting the skin of a mammal in need of such treatment with a composition comprising (a) about 0.01% to about 30%, by weight, of a hydroxycinnamic acid, a methoxycinnamic acid, or mixtures thereof, and (b) a compound having one or more hydroxy groups, a silicone fluid, or mixtures thereof, in a sufficient amount to maintain or improve at least visible indicia of rosacea.

3. The method of claim 1 or 2 comprising about 0.1% to about 20% of the hydroxycinnamic acid, methoxycinnamic acid, or mixtures thereof.

4. The method of claim 1 or 2 comprising about 0.5% to about 15% of the hydroxycinnamic acid, methoxycinnamic acid, or mixtures thereof.

5. The method of claim 1 or 2 wherein the hydroxycinnamic acid or methoxycinnamic acid is selected from the group consisting of 2-hydroxycinnamic acid, 3- hydroxycinnamic acid, 4-hydroxycinnamic acid, 2,3-dihydroxycinnamic acid, 2,4- dihydroxycinnamic acid, 3,4-dihydroxycinnamic acid, methoxycinnamic acid, 3- methoxycinnamic acid, 4-methoxycinnamic acid, 3-hydroxy-4-methoxycinnamic acid, 3- methoxy-4-hydrocinnamic acid, and mixtures thereof.

6. The method of claim 1 or 2 wherein the hydroxycinnamic acid is selected form the group consisting of 2-hydroxycinnamic acid, 3 -hydroxycinnamic acid, 4- hydroxycinnamic acid, and mixtures thereof.

7. The method of claim 1 or 2 wherein the hydroxycinnamic acid comprises 4-hydroxycinnamic acid.

8. The method of claim 1 or 2 wherein the hydroxycinnamic acid comprises ferulic acid, caffeic acid, cinnamic acid, gallic acid, rosmarinic acid, vanillic acid, and mixtures thereof.

9. The method of claim 2 wherein the compound having one or more hydroxy groups comprises a

ether of an ethylene glycol oligomer, a propylene glycol oligomer, or mixtures thereof.

10. The method of claim 9 wherein the

ether of an ethylene glycol oligomer or a propylene glycol oligomer has a general formula

wherein R¹ is

R² is hydrogen or methyl, or n is 2 or 3.

11. The method of claim 9 wherein the monoCi-4alkyl ether of an ethylene glycol oligomer or a propylene glycol oligomer is selected from the group consisting of ethoxydiglycol, methoxydiglycol, butoxydiglycol, methoxytriglycol, ethoxytriglycol, and mixtures thereof.

12. The method of claim 9 wherein the monoCi-₄alkyl ether of an ethylene glycol oligomer or a propylene glycol oligomer comprises ethoxydiglycol.

13. The method of claim 2 wherein the compound having one or more hydroxy groups is selected from the group consisting of a C2-C4 alcohol, a C₃-C₅ glycol, a polyethylene glycol, a polypropylene glycol, an ethylene oxide-propylene oxide block copolymer, a triol, a polyol, an ethoxylated glycerin, and mixtures thereof.

14. The method of claim 13 wherein the compound having one or more hydroxy groups is selected from the group consisting of propylene glycol, butylene glycol, pentylene glycol, glycereth-7 through glycereth-31 , PEG-4 through PEG-800, PPG-3 through PPG-69, ethanol, isopropyl alcohol, n-propanol, n-butanol, sec-butanol, t-butyl alcohol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, hexylene glycol, 1 ,2,6-hexanetriol, sorbitol, and mixtures thereof.

15. The method of claim 14 wherein the compound having one or more hydroxy groups comprises diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, PEG-4 through PEG-20, PPG-3 through PPG- 15, an ethylene oxide- propylene oxide block copolymer containing about 4 to about 20 total ethylene oxide and propylene oxide groups, or mixtures thereof.

16. The method of claim 15 wherein the compound having one or more hydroxy groups comprises diethylene glycol, PEG-4, PEG-6, PEG-8, PEG-9,PEG-10, PEG- 12, PEG- 16, PEG-18, PEG-20, PPG-3, PPG-9, PPG- 12, PPG-15, poloxamer 101 , and mixtures thereof.

17. The method of claim 2 wherein the compound having one or more hydroxy groups comprises a nonionic surfactant.

18. The method or claim 17 wherein the nonionic surfactant is selected from the group consisting of an ethoxylated octyl phenol, an ethoxylated nonyl phenol, an ethoxylated linear C_8-22 alcohol, a propoxylated linear C_8-22 alcohol, an ethoxylated and propoxylated linear C_8-22 alcohol, a polyethylene glycol ether of sorbitol, and mixtures thereof.

19. The method of claim 2 wherein the silicone fluid comprises a cyclic polydimethyl-siloxane, a linear polydimethylsiloxane, or a mixture thereof.

20. The method of claim 2 wherein the composition is a form of a solution, an emulsion, a gel, a microemulsion, or a nanoemulsion.

21. The method of claim 2 wherein the composition further comprises a topically applied compound selected from the group consisting of an antibiotic, a drug, a therapeutic agent, a deodorant, a skin conditioner, an antioxidant, an insect repellant, a counterirritant, a vitamin, a plant extract, a steroid, an antibacterial compound, an antifungal compound, an antiinflammatory compound, a topical anesthetic, an epidermal lipid replacement, a sunscreen, an optical brightener, a dermatitis or skin disease medication, and mixtures thereof.

22. The method of claim 2 wherein the composition further comprises a second compound useful in treating the symptoms of rosacea, said second compound selected from the group consisting of erythromycin, clindamycin, tetracycline, metronidazole, azelaic acid, adapalene, isotretinoin, sulfacetamide-sulfur, doxycycline, minocycline, sunscreens, and mixtures thereof.

23. The method of claim 1 or 2 wherein the mammalian skin is human skin.

24. The method of claim 1 or 2 wherein the hydroxycinnamic acid or methoxycinnamic acid penetrates a surface of the skin to an epidermis or dermis.

25. The method of claim 1 or 2 wherein the visual indicia of rosacea comprises at least one of skin flushing, skin redness, telangiectasias, pimples, pustules, and skin bumps.

26. The method of claim 2 wherein the skin is contacted with the composition in accordance with a treatment regimen of at least four weeks in duration.

27. The method of claim 26 wherein the skin is contacted with the composition at least one time per 24-hour period.

28. The method of claim 2 wherein the composition is selected from the group consisting of a skin lotion, a cream, a body rinse, a bath gel, a skin cleansing agent, a hair conditioner, a skin coloring composition, a foundation liquid, a foundation powder, a topical medicament, and a skin treatment.

29. A method of treating sunburn comprising contacting the skin of a mammal in need of such treatment with a sufficient amount of a hydroxycinnamic acid, a methoxycinnamic acid, or mixtures thereof.

30. A method of treating sunburn comprising contacting the skin of a mammal in need of such treatment with a composition comprising (a) about 0.01% to about 30%, by weight, of a hydroxycinnamic acid, a methoxycinnamic acid, or mixtures thereof, and (b) a compound having one or more hydroxy groups, a silicone fluid, or mixtures thereof.