Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-12-11
2003-11-18
Lovering, Richard D. (Department: 1712)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C424S059000, C424S060000, C510S130000, C510S136000, C510S417000, C514S845000, C514S846000, C514S943000, C516S029000, C516S030000
Reexamination Certificate
active
06649577
ABSTRACT:
This application is a 371 of PCT/EP99/04164, which was filed on Jun. 16, 1999.
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 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 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. However, there are only a few formulations in the prior art which are of sufficiently low-viscosity that they would, for example, be sprayable.
In addition, low-viscosity preparations of the prior art frequently have the disadvantage that they are unstable, and are limited to a narrow field of application or a limited choice of feed materials. Low-viscosity products in which, for example, strongly polar oils—such as the plant oils otherwise frequently used in commercially available products—are sufficiently stabilized are therefore currently not on the market.
W/O emulsions with a high water content and a low viscosity which moreover have storage stability, as is required for marketable products, can only be formulated in accordance with the prior art in a very complex manner. Accordingly, the supply of formulations of this type is extremely low. Nevertheless, formulations of this type could offer the consumer hitherto unknown cosmetic performances.
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.
Another object of the present invention was to provide preparations which can be charged with a high content of water-soluble and/or water-miscible substances having cosmetic or dermatological activity, without impairing the galenical quality-or other properties of the preparations.
According to K. J. Lissant: The Geometry of High-Internal-Phase-Ratio Emulsions; Journal of Colloid and Interface Science 22, 462-468 (1966), emulsions with an internal phase of more than 70% are defined as so-called high internal phase emulsions. The preparation of stable, flowable water-in-oil emulsions with a water content of more than 70% is very difficult. In particular, “high internal phase” W/O emulsions with a very high water content of more than 85% (“very high internal phase” W/O emulsions) are not accessible.
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. Therefore, only water-in-oil emulsions with a solid to semisolid consistency are obtainable. Even the use of polar lipids, by virtue of which lower-viscosity water-in-oil emulsions are usually obtained, does not lead to the desired success.
Surprisingly, it has been found that water-in-oil emulsions
(a) with a viscosity of at most 5000 mPa·s
(b) with a content of water and optionally water-soluble substances totalling at least 75% by weight, and with a content of lipids, emulsifiers and lipophilic constituents totalling at most 15%, based in each case on the total weight of the preparations,
(c) the oil phase of which comprises at least 75% of one or more substances chosen from the groups of
nonpolar lipids which are liquid at room temperature and have a polarity of greater than 30 mN/m, and/or
silicones of any polarity this weight proportion being based on the total weight of the oil phase,
(d) comprising at least one interface-active substance chosen from the group of substances of the general formula (I)
where A and A′ are identical or different organic radicals chosen from the group of branched and unbranched, saturated and unsaturated alkyl and acyl radicals and hydroxyacyl radicals having 10-30 carbon atoms, and also from the group of hydroxyacyl groups connected to one another via ester functions, in accordance with the scheme
where R′ is chosen from the group of branched and unbranched alkyl groups having 1 to 20 carbon atoms and R″ is chosen from the group of branched and unbranched alkylene groups having 1 to 20 carbon atoms, and b can assume numbers from 0 to 200,
a is a number from 1 to 100, preferably 2 to 60, in particular 5 to 40,
X is a single bond or the group
R
1
and R
2
independently of one another are chosen from the group consisting of H and methyl,
R
3
is chosen from the group consisting of H, and the branched and unbranched, saturated and unsaturated alkyl and acyl radicals having 1 to 20 carbon atoms overcome the disadvantages of the prior art.
The structural formula must not be interpreted as meaning that because of the index a, all of the radicals R
1
, R
2
and R
3
represented in the brackets must in each case be identical throughout the entire molecule. Instead, these radicals can be freely chosen in each of the a fragments
It is possible and advantageous to choose the total content of water and water-soluble substances of the W/O emulsions according to the invention to be greater than 80% by weight, in particular greater than 85% by weight, in each case based on the total weight of the preparations.
An example of interface-active substances which can be used particularly advantageously for the purposes of the present invention is polyethylene glycol-30 dipolyhydroxystearate (PEG-30 dipolyhydroxystearate), which is sold by ICI Surfactants under the trade name ARLACEL®
Bleckmann Andreas
Kröpke Rainer
Schneider Günther
Beiersdorf AG
Lovering Richard D.
Norris & McLaughlin & Marcus
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