Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
2001-05-08
2002-05-21
Dees, Jose G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S059000, C424S400000, C514S844000, C514S938000
Reexamination Certificate
active
06391324
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to compositions comprising pulegone and methods of improving the cosmetic appearance of the skin by topically applying such compositions to the skin.
BACKGROUND OF THE INVENTION
The human skin consists of two major layers: the dermis, the bottom thicker layer, and the epidermis, the top thinner layer. The dermis is the layer that provides strength, elasticity, and thickness to the skin. With aging, the thickness of the dermal layer is reduced, thus, partially causing the formation of wrinkles in aging skin. The top layer of the skin, the epidermis, provides the resilience and the barrier properties of the skin. The epidermis is composed of many different cell types. Keratinocytes are the major cell type of the epidermis, consisting of nearly 75 to 80% of the total number of cells in the human epidermis.
The keratinocytes reside in four distinct stages of differentiation within the epidermis. Epidermal differentiation is important to providing essential functions of the skin. Namely, epidermal differentiation aids the formation of a barrier layer that protects the body against the harmful substances in the environment and prevents loss of water from the body. Proper formation of the barrier layer of the epidermis requires skin cells to develop correctly through space and time and demands the synchronized production of essential lipid materials such as ceramides, cholesterol and fatty acids. Such lipid materials are formed by cells in the granular layer of the epidermis and are used to compose lipid layers that in turn become the skin's essential protective barrier layer. The lipid layers act as a water barrier to prevent water loss from the skin, and consequently, prevent the appearance of aged, dry, or wrinkled skin. As such, disruption of the skin's barrier layer and impairment of its functioning are associated with skin conditions such as atopic dermatitis, psoriasis, irritation and dry skin.
In normal skin, if the barrier function is disturbed, the epidermis re-synthesizes the deficient lipids. However, under certain conditions, a reduced capacity for re-synthesis may occur. Such is the case in aging or dry skin where skin lipid levels are in any case sub-normal and cell metabolism is impaired. Decreased uptake and utilization of glucose can lead to decreased metabolism and skin cell turnover, thereby leading to the appearance of aged, dry and flaky skin. Materials that enhance keratinocyte differentiation, increase lipid expression, or stimulate cell metabolism, may be useful in reversing such conditions to promote healthy skin.
Pulegone (5-Methyl-2-(1-methylethylidene)cyclohexanone) is an essential oil which may be found in pennyroyal, a naturally occurring plant. Prior art teaches the use of pulegone in applications such as pest repellants or perfumes. For example, U.S. Pat. No. 5,106,622 issued to Sherwood et al. cites the use of pennyroyal oil (~85% pulegone) in an insect repellent composition. U.S. Pat. No. 4,193,986 issued to Trinh et al. refers to the use of oil of pennyroyal as a component of a pest repellent for pets and animals. JP 08143419 refers to the use of pulegone in a bath composition for the purpose of repelling mites. U.S. Pat. No. 5,466,452 issued to Whittle refers to the use of extracts of Chinese herbs, some of which contain pulegone, for the preparation of materials to be taken orally or applied topically for relief of skin problems.
U.S. Pat. No. 5,871,718 issued to Lucas et al. and U.S. Pat. No. 5,874,070 issued to Trinh et al. disclose odor-absorbing compositions which may be used on skin. The compositions contain cyclodextrin, a molecule capable of complexing odor molecules. The compositions also include a perfume, which may be pulegone. Both patents teach that perfumes in the compositions (such as pulegone) tend to complex with cyclodextrins to reduce the concentration of the perfume actually delivered to the skin.
The prior art cited above does not disclose cosmetic compositions that can deliver solubilized pulegone to provide the combined benefit of enhanced differentiation and enhanced expression of lipids essential to barrier function. Therefore, a need exists for cosmetic compositions that can deliver pulegone to effectively improve the cosmetic appearance of skin.
SUMMARY OF THE INVENTION
The present invention relates to an oil in water emulsion of a cosmetic skin care composition comprising:
(a) from about 0.001% to about 10% of solubilized pulegone of Formula I:
(b) a moisturizing agent; and
(c) a cosmetically acceptable vehicle.
DETAILED DESCRIPTION OF THE INVENTION
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts or ratios of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word “about.” All amounts are by weight of the final composition, unless otherwise specified.
The term “skin” as used herein includes the skin on the face, neck, chest, back, arms, legs, hands, and scalp.
The term “solubilized” as used herein means that at least 90% of pulegone present in the final composition is solubilized.
An increase in transglutaminase-1 expression and ceramide expression can reduce dry skin by improving barrier formation as well as improving cell function and metabolism. Consequently, the appearance of lines, wrinkles, and aged skin are significantly reduced. Moreover, enhanced keratinocyte differentiation and lipid production and improved glucose uptake result in improved skin color, radiance, finish, and an overall healthy and youthful appearance of the skin. It is to such improvements that the present invention is directed.
According to the present invention, solubilized pulegone increases transglutaminase-1 expression (a marker for differentiation), ceramide expression, and glucose uptake.
All amounts are by weight of an oil-in-water emulsion, unless otherwise indicated.
Pulegone (5-Methyl-2-(1-methylethylidene)cyclohexanone) is an essential oil which is found in pennyroyal. Pulegone may be obtained from Sigma. Pulegone has the following structural formula I:
Pulegone must be solubilized and uncomplexed in order to deliver benefits to the skin. Particularly, solubilizing pulegone avoids evaporation of the pulegone within the composition before delivery into the skin. Moreover, if the pulegone is complexed, it is difficult to ensure that at least a minimum amount of pulegone is available for skin benefit. In a preferred embodiment, pulegone is incorporated in the inventive compositions in an amount of from 0.001% to 10%, preferably from 1% to 7%, and most preferably from 2% to 5%.
One fundamentally important criterion by which many topical lotions/creams must be measured is their ability to act as efficient skin moisturizers. Skin moisturizing ability is of extreme importance for topical lotions/creams in that consumers regard scaly, dry skin as unsightly and undesirable. Topical lotions that have the added benefit of enhancing skin moisture retention capabilities have a significant added benefit above and beyond the utility of their active ingredient. Thus, the inventive composition also comprises a moisturizing agent for imparting moisturizing characteristics and sensory benefits to the skin without impeding the benefits of pulegone on the skin.
The moisturizing agent of the present invention is selected so that the moisturizing agent does not get emulsified in the oil phase of an emulsion and therefore effectively deposits on the skin. Thus, the moisturizing agent is preferably water soluble to prevent emulsification within the inventive composition prior to application onto the skin. In the preferred embodiment, the moisturizing agent is selected from the group consisting of: propylene glycol, sorbitol, butylene, glycerin, cetostearyl alcohol, cetyl palmitate, myristyl alcohol, and palmitic alcohol, and mixtures thereof, due to commercial availability and water solubility. Most preferably, the moisturizing agen
Carson Robert
Granger Stewart Paton
Patel Krupa
Pillai Sreekumar
Dees Jos,e G.
Lamm Marina
Plotkin Ellen
Unilever Home & Personal Care USA, Division of Conopco
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