Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Wearing apparel – fabric – or cloth
Reexamination Certificate
2000-05-01
2001-09-11
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Wearing apparel, fabric, or cloth
C424S400000, C424S401000, C424S404000
Reexamination Certificate
active
06287582
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns single use towelettes for cosmetically delivering alpha-hydroxycarboxylic acids.
THE RELATED ART
Alpha-hydroxycarboxylic acids and their derivatives have widely been advertised as treatment for maintaining a youthful look. These substances are said to control development of facial fine lines and wrinkles. Formulation of these substances have been difficult. Among the problems have been compatibility with carrier systems, physical stability and skin irritation. Particularly difficult to formulate are low pH systems.
U.S. Pat. No. 5,091,171 (Yu et al.) was one of the first documents describing the use of alpha-hydroxycarboxylic acids as being effective against the appearance of fine lines and wrinkles. Subsequent thereto a vast literature and many commercial products were generated based on the efficacy of these materials. Most often the formulations were of the cream or lotion type. One problem with these formulations is that they do not always evenly distribute over the applied surfaces. Secondly, any time an active treated surface is followed by a cleansing, the active washes away. Methods to maintain alpha-hydroxycarboxylic acids on a skin surface are needed which are not as susceptible to subsequent cleansing actions. Irritation has also been of great concern because the formulations are generally of low pH.
WO 96/11572 (Moberg) has utilized a variety of acids including the alpha-hydroxy substance known as lactic acid in an aqueous hexylene glycol formula impregnated onto textiles or refreshing napkins. These were employed to overcome the problem of microbial growth on skin and served as a disinfection treatment.
U.S. Pat. No. 4,828,912 (Hossain et al.) and U.S. Pat. No. 4,764,418 (Kuenn et al.) describe virucidal tissue products directed at controlling disease inducing organisms such as viruses and the common cold. Carboxylic acids such as citric, malic, succinic and benzoic acids are formulated with surfactants and a carrier for impregnation into facial tissues or other non-woven materials.
None of the above disclosures have been concerned with the issue of stickiness of the alpha-hydroxycarboxylic acids once they have been deposited by the towelette onto the skin. Neither has there been any discussion with respect to odor control which may arise in low pH systems.
Accordingly, it is an object of the present invention to provide a product and method for both cleansing skin and reducing the signs of aging.
Another object of the present invention is to provide a product and method which deposited alpha-hydroxycarboxylic acids in a manner that avoids formation of sticky residues on the skin.
Still another object of the present invention is to provide a product delivering alpha-hydroxycarboxylic acids in a formulation that avoids formation of foul odors.
These and other objects of the present invention will become more apparent from the following summary and detailed discussion which follow.
SUMMARY OF THE INVENTION
A towelette product is provided which includes:
(a) a water-insoluble substrate;
(b) a cosmetic composition impregnated into the substrate including:
(i) an alpha or beta-hydroxycarboxylic acid;
(ii) a silicone microemulsion;
(iii) the composition in water having a pH no higher than about 6.5.
Silicone microemulsions of the present invention operate to provide both stability to the composition and counteract any stickiness which may occur when the alpha-hydroxycarboxylic acids are deposited onto the skin.
Surfactants, especially mild surfactants such as those of the amphoteric type may in the presence of low pH decompose thereby emitting foul odors. Silicone microemulsions of the present invention have also found youthfulness in counteracting generation of the foul odors.
DETAILED DESCRIPTION OF THE INVENTION
Now it has been found that towelettes impregnated with alpha-hydroxycarboxylic acids can be delivered to the skin without imparting any stickiness. Silicone microemulsions solve this problem. Normally creams, lotions and other types of cosmetic vehicles containing the alpha-hydroxycarboxylic acids contain emollients. For instance these emollients may be esters, hydrocarbons or dimethicone oils. These emollients deposit on the skin along with the actives. The presence of the emollients obscures any stickiness which may result from water or carrier evaporation leaving dried active behind. Unfortunately towelette products cannot be impregnated with fluids of too high viscosity. Towelettes will not adequately wet out where the fluid to be impregnated is too thick. Low viscosity fluids which must be used with towelettes are susceptible to poor emulsion stability. Large amounts of emollients are difficult to formulate into these systems. Consequently, actives such as alpha-hydroxycarboxylic acids deposit in a sticky manner onto skin from the low viscosity fluids spread thereon by the towelettes.
A first necessary aspect of the present invention is that of a substrate. Preferably the substrate is a water insoluble substance. By “water insoluble” is meant the substrate does not dissolve in or readily break apart upon immersion in water. Another advantage of the substrate in combination with the active is that the former helps the active penetrate. The substrate is also much better than a mere liquid or gel formulation in the accurate application to the skin and avoidance of sensitive areas such as inadvertently directing the astringent composition to areas of the eye thereby irritating same.
A wide variety of materials can be used as the substrate. The following nonlimiting characteristics are desirable: (I) sufficient wet strength for use, (ii) sufficient abrasivity, (iii) sufficient loft and porosity, (iv) sufficient thickness, (v) appropriate size, and (vi) non-reactive with components of the impregnating composition.
Nonlimiting examples of suitable substrates which meet the above criteria include nonwoven substrates, woven substrates, hydroentangled substrates, air entangled substrates and the like. Preferred embodiments employ nonwoven substrates since they are economical and readily available in a variety of materials. By nonwoven is meant that the layer is comprised of fibers which are not woven into a fabric but rather are formed into a sheet, particularly a tissue. The fibers can either be random (i.e., randomly aligned) or they can be carded (i.e. combed to be oriented in primarily one direction). Furthermore, the nonwoven substrate can be composed of a combination of layers of random and carded fibers.
Nonwoven substrates may be comprised of a variety of materials both natural and synthetic. By natural is meant that the materials are derived from plants, animals, insects or byproducts. By synthetic is meant that the materials are obtained primarily from various man-made materials or from material that is usually a fibrous web comprising any of the common synthetic or natural textile-length fibers, or mixtures thereof.
Nonlimiting examples of natural materials useful in the present invention are silk fibers, keratin fibers and cellulosic fibers. Nonlimiting examples of keratin fibers include those selected from the group consisting of wool fibers, camel hair fibers, and the like. Nonlimiting examples of cellulosic fibers include those selected from the group consisting of wood pulp fibers, cotton fibers, hemp fibers, jute fibers, flax fibers, and mixtures thereof. Wood pulp fibers are preferred while all cotton fibers (e.g. cotton pads) are normally avoided.
Nonlimiting examples of synthetic materials useful in the present invention include those selected from the group consisting of acetate fibers, acrylic fibers, cellulose ester fibers, modacrylic fibers, polyamide fibers, polyester fibers, polyolefin fibers, polyvinyl alcohol fibers, rayon fibers and mixtures thereof. Examples of some of these synthetic materials include acrylics such as Acrilan®, Creslan®, and the acrylonitrile-based fiber, Orlon®; cellulose ester fibers such as cellulose acetate, Arnel®, and Acele®; polyamides such as Nylons (e.g., Nylon
Gott Robert Edward
Slavtcheff Craig Stephen
Znaiden Alexander Paul
Evans Charesse L.
Honig Milton L.
Page Thurman K.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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