Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
2000-07-27
2002-07-23
Dees, Jose G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S059000, C424S400000, C514S847000, C514S873000, C514S937000, C516S021000, C516S028000
Reexamination Certificate
active
06423326
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to stable cold-mix water-in-oil emulsions and methods for preparing such emulsions. More specifically, the invention relates to cold-mix water-in-oil emulsions comprising oil (i.e., an emollient), water and an emulsification system comprising a quaternary ammonium-based low HLB emulsifier and optional co-emulsifiers. The present invention relates to cosmetic compositions which contain the inventive cold-mix oil and water emulsions. These cosmetic compositions are typically in the form of lotions, gels, or sprays, which provide improved moisturization, skin feel, skin care, and appearance benefits and reduced greasiness, together with excellent rub-in and absorption characteristics. The instant invention also relates to cold-mix water-in-oil sunscreen emulsions and methods for preparing such sunscreen emulsions. The emulsions of the instant invention generally display excellent extended duration stability characteristics at both normal and elevated temperatures.
DESCRIPTION OF RELATED ART
Conventional cosmetic cream and lotion compositions, for example those in Sagarin,
Cosmetics Science and Technology,
2nd Ed., Vol.1, Wiley Interscience (1972) and
Encyclopedia of Chemical Technology,
3rd Ed., Vol. 7 are known to provide varying degrees of emolliency, barrier and water-retention (moisturizing) benefits. However, these conventional compositions are often lacking in desirable skin feel properties (i.e., they often feel very greasy when applied to the skin), as well as having poor rub-in, absorption and residue characteristics. Additional oil-in-water emulsion disclosures include for example those found in U.S. Pat. No. 5,759,558 (to Epstein, issued Jun. 2, 1998), U.S. Pat. No. 5,656,280 (to Helene Curtis, issued Aug. 12, 1997), U.S. Pat. No. 5,589,117 (to Helene Curtis, issued Dec. 31, 1996), U.S. Pat. No. 5,756,108 (to L'Oreal, issued May 26, 1998), U.S. Pat. No. 5,759,557 (to Epstein, issued Jun. 2, 1998), U.S. Pat. No. 5,543,136 (to NuSkin International, issued Aug. 6, 1996), U.S. Pat. No. 4,389,418 (to S. C. Johnson & Sons, issued Jun. 21, 1983), EP 0715842 A2 (Helene Curtis, filed Nov. 10, 1995), and WO 98/55086 (Stewart, filed Jun. 4, 1998).
While water-in-oil compositions are well known, they are difficult to prepare as they normally require heating to high temperatures (i.e., greater than 50° C.) and generally have not enjoyed commercial success and/or consumer popularity due to unacceptable greasiness. The disadvantages of preparing water-in-oil emulsions at higher temperatures include promotion of unacceptable water loss through evaporation, time-consummation, inefficient processing, and the added processing expense of heating the emulsion.
The foregoing description of the related art indicates that a variety of water-in-oil emulsions are known, along with a variety of processes to produce such emulsions, all of which have various end-use property limitations and/or undesirable processing limitations. A need exists for a superior processable water-in-oil emulsion which can be prepared at relatively low temperatures, i.e., at about 25° C. Additionally there is a need for such processable emulsions which do not impart a greasy feel to skin upon application, while at the same time such emulsion possess acceptable rub-in, absorption and residue characteristics.
Surprisingly, compositions of the instant invention can be prepared with little to no heat, i.e., they are prepared as a water-in-oil emulsion which is capable of being substantially completely emulsified and stable at about 25° C. In additional to highly desirable low temperature preparation, these emulsions are stable, light and have a non-greasy feel when applied to the skin. The present invention provides skin-care cosmetic compositions which provide improved moisturization, absorption, skin feel, skin care and appearance characteristics and, which in particular, provide improved short and longer term moisturizing effectiveness, while at the same time reducing stickiness and avoiding a greasy feel on the skin. The compositions also display excellent stability characteristics at both normal and elevated temperatures.
It is therefore an object of the present invention to provide cold-mix water-in-oil emulsions comprising oil (i.e., an emollient), water and an emulsification system comprising a quaternary ammonium-based low HLB emulsifier and optional co-emulsifiers. Another object of the invention is to provide cold-mix water-in-oil sunscreen emulsions comprising oil (i.e., an emollient), water, an emulsification system comprising a quaternary ammonium-based low HLB emulsifier and optional co-emulsifiers, and a sun screen agent. Another objection of the invention relates to bulk and finished cosmetic compositions (lotions, gels, sprays) which contain the inventive cold-mix water-in-oil emulsions and cold-mix water-in-oil sunscreen emulsions. The invention further relates to cold-mix methods of preparing the cold-mix water-in-oil emulsions disclosed, including the cold-mix water-in-oil sunscreen emulsions described herein.
It is another object of the present invention to provide methods for moisturizing and/or providing sun protection to human skin, comprising applying to the skin the cold-mix water-in-oil emulsions and/or the cold-mix water-in-oil sunscreen emulsions described herein.
These and other objects and advantages are achieved by the invention description below.
SUMMARY OF THE INVENTION
It has been surprisingly discovered that highly stable water-in-oil emulsions can be prepared as a cold mix water-in-oil emulsions at about 25° C. The present invention also encompasses cold mix water-in-oil sunscreen emulsions.
Accordingly, the present invention encompasses a cold-mix water-in-oil emulsion comprising:
(a) from about 10% to about 50% by weight of an emollient;
(b) from about 0.5% to about 30% by weight of an emulsification system comprising a low HLB emulsifier of the formula:
where R is substantially linear nor-oleyl;
(c) from about 0% to about 35% of a co-emulsifier; and
(d) water;
the emulsification system and co-emulsifier substantially permanently maintaining the water and emollient as an emulsion, the emulsion capable of being substantially completely emulsified and stable at about 25° C.
The present invention encompasses a cold-mix water-in-oil sunscreen emulsion comprising:
(a) from about 10% to about 30% by weight of an emollient; and
(b) from about 0.5% to about 30% by weight of an emulsification system comprising a low HLB emulsifier of the formula:
where R is substantially linear nor-oleyl;
(c) from about 0% to about 35% a co-emulsifier;
(d) a sunscreen agent; and
(e) water;
wherein the emulsification system and the co-emulsifier substantially permanently maintain the water and emollient as a sunscreen emulsion, the sunscreen emulsion capable of being substantially completely emulsified and stable at about 25° C.
The invention also includes methods for making and using such emulsions. The emulsions described herein are primarily useful in finished sun screening formulations for application to human skin and in finished moisturizing creams, lotions, gels, and sprays for application to human skin. The inventive emulsions may be topically applied to human skin to moisturize the skin and/or may also be applied to human skin before prolonged exposure to light radiation to prevent the erythema normally observed after such exposure, i.e. the prevention of sun burn.
DETAILED DESCRIPTION OF THE INVENTION
The present invention encompasses novel cold-mix water-in-oil emulsions utilizing quaternary ammonium-based low HLB emulsifiers. The emulsions are readily prepared at low temperatures, i.e. at about 25° C. Further, the emulsification system and the co-emulsifier substantially permanently maintain the water and emollient as a water-in-oil emulsion, where such emulsion is substantially completely emulsified and stable at about 25° C.; by this it is meant that the water-in-oil emulsion and/or water-in-oil sunscreen
Dees Jos,e G.
Lamm Marina
McDonnell & Boehnen Hulbert & Berghoff
Stepan Company
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