PREPARATIONS OF THE W/O EMULSION TYPE WITH AN INCREASED...

Details PREPARATIONS OF THE W/O EMULSION TYPE WITH AN INCREASED... PREPARATIONS OF THE W/O EMULSION TYPE WITH AN INCREASED...

2000-05-23

2002-05-07

Dudash, Diana (Department: 1619)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Cosmetic, antiperspirant, dentifrice

C424S078030, C424S070210, C424S070120, C424S063000, C424S069000

Reexamination Certificate

active

06383503

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to cosmetic and dermatological preparations, in particular those of the water-in-oil type, to processes for their preparation and to their use for cosmetic and medicinal purposes.
The human skin is man's largest organ and performs a number of vital functions. Having an average area of about 2 m
2
in adults, it has a prominent role as a protective and sensory organ. The purpose of this organ is to transmit and avert mechanical, thermal, actinic, chemical and biological stimuli. In addition, it has an important role as a regulatory and target organ in human metabolism.
The main aim of skin care in the cosmetics sense is to strengthen or rebuild the skin's natural function as a barrier against environmental influences (e.g. dirt, chemicals, microorganisms) and against the loss of endogenous substances (e.g. water, natural fats, electrolytes), and also to assist its horny layer in its natural regeneration ability where damage has occurred.
If the barrier properties of the skin are impaired, increased resorption of toxic or allergenic substances or infection by microorganisms may result, leading to toxic or allergic skin reactions.
Another aim of skin care is to compensate for the loss by the skin of sebum and water caused by daily washing. This is particularly important if the natural regeneration ability is inadequate. Furthermore, skin care products should protect against environmental influences, in particular against sun and wind, and delay skin ageing.
Medicinal topical compositions usually comprise one or more medicaments in an effective concentration. For the sake of simplicity, in order to clearly distinguish between cosmetic and medicinal use and corresponding products, reference is made to the legal provisions in the Federal Republic of Germany (e.g. Cosmetics Directive, Foods and Drugs Act).
Emulsions are generally taken to mean heterogeneous systems which consist of two liquids which are immiscible or miscible with one another only to a limited extent, which are usually referred to as phases. In an emulsion, one of the two liquids is dispersed in the form of very fine droplets in the other liquid.
If the two liquids are water and oil and oil droplets are very finely dispersed in water, this is an oil-in-water emulsion (O/W emulsion, e.g. milk). The basic character of an OIW emulsion is determined by the water. In the case of a water-in-oil emulsion (W/O emulsion, e.g. butter), the principle is reversed, the basic structure being determined here by the oil.
The person skilled in the art is of course aware of a large number of ways to formulate stable W/O preparations for cosmetic or dermatological use, for example in the form of creams and ointments which can be spread in the range from room temperature to skin temperature, or as lotions and milks, which are more likely flowable in this temperature range.
SUMMARY OF THE INVENTION
The object of the present invention was to provide preparations which can be formulated with a high or very high content of water-soluble and/or water-miscible substances, without impairing the galenical quality or other properties of the preparations.
According to K. J. Lissant:
The Geometry of High
-
Intemal
-
Phase
-
Ratio Emulsions;
Journal of Colloid and Interface Science 22, 462-468 (1966), emulsions with an internal phase of >70% are defined as high internal phase emulsions. The preparation of stable, solid to semi-solid high internal phase water-in-oil emulsions, in particular those with a relatively high water content of 85% (“very high internal phase water-in-oil emulsions”) and nevertheless with very good sensory properties is an unsolved problem. As a result of this very high water content in the emulsions, the latter “break” on the skin particularly rapidly (sensorily unpleasant) into their main constituents (hydrophilic and lipophilic components). Furthermore, the lipophilic components also separate into their individual constituents, meaning that the lipids “slide away” from one another on the skin (sensorily unpleasant).
The technique of varying the phase volume ratio (i.e. incorporating higher amounts of liquid lipids) which is usually used for water-in-oil emulsions can, because of the low lipid content, be used only to a limited extent in the case of high internal phase W/O emulsions, or not at all in the case of very high internal phase W/O emulsions.
DETAILED DESCRIPTION
Surprisingly, it has been found that water-in-oil emulsions
(a) with a content of water and optionally water-soluble substances totalling at least 80% by weight, and with a content of lipids, emulsifiers and lipophilic constituents totalling at most 20% by weight, based in each case on the total weight of the preparations,
(b) comprising at least one surface-active substance chosen from the group of alkylmethicone copolyols and/or alkyldimethicone copolyols,
(c) comprising one or more lipid components which include the lipid phase of the emulsion,
(d) where the weight ratio of (b) to (c) is chosen from the range 0.05 to 0.30, preferably 0.06 to 0.14,
(e) if the water content is between 75 and 80% by weight, comprising one or more cationic polymers
(f) if the water content is more than 80% by weight, not comprising a cationic polymer overcome the disadvantages of the prior art.
Surprisingly, the preparations according to the invention are extremely pleasant to use on the skin and are characterized by very high cosmetic elegance. Use of the compositions, which are familiar to persons skilled in the art without further inventive activity, makes it possible to achieve virtually any desired viscosities, meaning that the present invention can, for example, be formed as a flowable application form (for example a lotion) or as a semi-solid to solid preparation (for example as a cream).
One example of surface-active substances which are to be used particularly advantageously for the purposes of the present invention is cetyldimethicone copolyol, which is sold by Th. Goldschmidt AG under the trade name ABIL® EM 90.
Furthermore, the emulsifier laurylmethicone copolyol has been found to be particularly advantageous, which is obtainable under the trade name Dow Corning® 5200 Formulation Aid from Dow Corning Ltd.
The total amount of the surface-active substances used according to the invention in the finished cosmetic or dermatological preparations is advantageously chosen from the range 0.075-7.5% by weight, preferably 0.1-5.0% by weight, in particular 1.0-3.0% by weight, based on the total weight of the preparations.
The preparations according to the invention particularly advantageously comprise more than 85% by weight, in particular more than 88% by weight, of water and optionally water-soluble substances, based on the total weight of the preparations.
Surprisingly, it has in particular been found that the addition of from 0.01 to 10% (preferably 0.25-1.25%) of suitable cationic polymers makes it possible to prepare stable, solid to semisolid and/or flowable very high internal phase emulsions, which have excellent sensory properties.
Suitable cationic polymers are, for example, cationic cellulose derivatives (e.g. Polymer JR 400® from Amerchol), cationic starch, copolymers of diallyl-ammonium salts and acrylamides, quaternized vinypyrrolidone/vinylimidazole polymers (e.g. Luviquat® from BASF), condensation products of polyglycols and amines, quaternized collagen polypeptides (e.g. Lamequat® L from Grünau-Henkel), quaternized wheat polypeptides, polyethyleneimine, cationic silicone polymers, copolymers of adipic acid with dimethylaminohydroxy-propyidiethylenetriamine, copolymers of acrylic acid with dimethyidiallyl-ammonium chloride (e.g. Merquate® 550 from Chemviron), polyaminopolyamides, cationic chitin derivatives, cationic guar gum (e.g. Jaguar® CBS from Hoechst Celanese), quaternized ammonium salt polymers (e.g. Mirapol® AD-1 from Miranol), and cationic biopolymers, such as, for example, chitosan (average molecular weight of from 50,000 to 2,000,000 g/mol [determined by means of gel p

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