Reduced lipid flowable preparations

Details Reduced lipid flowable preparations Reduced lipid flowable preparations

2000-06-12

2003-01-07

Travers, Russell (Department: 1619)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Cosmetic, antiperspirant, dentifrice

C424S060000, C424S065000, C424S070900, C424S070190, C514S938000

Reexamination Certificate

active

06503518

ABSTRACT:

The present invention relates to cosmetic and dermatological preparations, in particular those of the oil-in-water 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).
The term emulsion generally means 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 O/W 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 O/W 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. However, the prior art recognizes only a few formulations which are of such low viscosity that they would, for example, be sprayable.
In addition, low-viscosity preparations of the prior art often have the disadvantage that they are unstable and are limited to a narrow range of application or to a restricted choice of starting materials. Low-viscosity products in which, for example, strong polar oils—such as the vegetable oils frequently used in commercially available products—are sufficiently stabilized cannot therefore be currently found on the market.
O/W emulsions with a low viscosity and which have a storage stability which is required for marketable products can only be formulated according to the prior art in a very complex manner. Accordingly, the supply of such formulations is extremely low. Nevertheless, such formulations could offer the consumer cosmetic effects which are hitherto unknown.
An object of the present invention was to provide preparations which have a very low viscosity and do not have the disadvantages of the prior art.
Surprisingly, these objects are achieved by low-viscosity cosmetic or dermatological preparations comprising
(I) one or more partially neutralized esters of monoglycerides and/or diglycerides of saturated fatty acids with citric acid,
(II) one or more fatty alcohols chosen from the group of branched and unbranched alkyl alcohols having 12 to 40 carbon atoms,
(III) a water phase,
(IV) from 0 to 10% by weight of a lipid phase, based on the total weight of the preparations,
where the weight ratio of the sum of the constituents from (I) and (II): (IV) is chosen from the range from 20:1 to 1:5.
It had therefore not been foreseen by the person skilled in the art that the preparations according to the invention
would be more effective as moisture-donating preparations,
would be easier to formulate,
would better promote skin smoothing,
would be characterized by a better care action,
would be better vehicles for cosmetic and medicinal-dermatological active ingredients,
would have better sensory properties, such as, for example, the dispersibility on the skin or absorption into the skin,
have higher stability against splitting into oil and water phases, and
would exhibit better biocompatibility than the preparations of the prior art.
The preparations according to the invention therefore represent an enrichment of the prior art with regard to flowable O/W emulsions.
The invention further relates to the use of
(I) one or more partially neutralized esters of monoglycerides and/or diglycerides of saturated fatty acids with citric acid,
(II) one or more fatty alcohols chosen from the group of branched and unbranched alkyl alcohols having 12 to 40 carbon atoms,
(III) a water phase,
(IV) from 0 to 10% by weight of a lipid phase, based on the total weight of the preparations,
where the weight ratio of the sum of the constituents from (I) and (II): (IV) is chosen from the range of from 20:1 to 1:5, for the preparation of low-viscosity preparations, in particular of O/W emulsions.
The lipid content of the preparations obtainable according to the invention can advantageously be varied from 0% by weight up to 10% by weight, with equally favourable results being achieved. In cases where no lipid is present, the system is not an emulsion, but a system which is most appropriately referred to as an emulsifier gel.
Preparations according to the invention preferably comprise up to 7.5% by weight of a lipid phase and are then O/M emulsions. Preparations according to the invention particularly advantageously comprise up to 6% by weight of a lipid phase. Preparations according to the invention particularly preferably comprise 2 to 4% by weight of a lipid phase, in particular about 3% by weight, in each case based on the total weight of the preparations.
According to the teaching presented herein, O/M emulsions are obtainable whose viscosity at 25° C. is less than 2500 mPa·s (=millipascal seconds), in particular less than 2000 mPa·s (measured using a Viscotester VT-02, Haake).
A particularly advantageous citric ester is glyceryl stearate citrate. Such citric esters are obtainable, for example, under the product name “IMWITOR® 370” from Hüls AG.
The total amount of one or more glycerol esters of &agr;-hydroxycarboxylic acids and saturated fatty acids used according to the invention in the finished cosmetic or dermatological preparations is advantageously chosen from the range 0.1-10.0% by weight, preferably 0.5-6.0% by weight, based on the total weight of the preparations.
The preferred fatty alcohol used according to the invention is cetylstearyl alcohol (a mixture of 1-hexadecanol and 1-octadecanol in equal amounts).
The total amount of one or more fatty alcohols used according to the invention in the finished cosmetic or dermatological preparations is advantageously chosen from the range 0.1-10.0% by weight, preferably 0.5-6.0% by weight, based on the total weight of the preparations.
According to the invention, it is advantageous to choose weight ratios of one or more partially neutralized esters of monoglycerides and/or diglycerides of saturated fatty acids with citric acid on the one hand and fatty alcohols on

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