High oil containing anhydrous foamable compositions

This invention relates to high oil containing anhydrous foamable compositions. It is based on the discovery that petroleum jelly (also known as white petrolatum) unmodified or modified with mineral oil may be formulated with a certain organic detergent into anhydrous, cosmetically elegant creams which are unique in that they present adequate foaming properties, cleanse exceptionally well and simultaneously deposit a film of petrolatum on the surface. Because of the anhydrous cleansing compositions, many active drugs which in general are incompatible in presence of water may be incorporated into a medicated cleansing product.

More particularly, the present invention relates to essentially anhydrous base compositions containing an oily component of non-modified petroleum jelly or petroleum jelly modified with mineral oil and a mild detergent component, which is sodium cocoyl isethionate, in a high amount in order to impart to the base foaming characteristics when subsequently combined with water in use. The base compositions in accordance with the present invention are useful not only in cosmetic and pharmaceutical compositions, but also in cleansing compositions in general household use.

EP-A-203750 describes a synthetic detergent bar which may include an acyl isethionate as a surfactant and petrolatum and mineral oil as potential moisturizers. To achieve optimal foaming properties and skin feel, this reference requires a mixture of surfactants with the addition of up to 5% soap, and the use of polymeric skin feel and skin mildness aids. This contrasts with the present invention which requires merely a single mild detergent, sodium cocyl isethionate, to achieve good foaming and skin feel properties. Moreover, EP-A-203750 teaches the addition of 20-70% water to form a cream, thus preventing the resulting composition from being anhydrous like the present composition.

Prior to the present invention there have been many attempts to obtain foamable preparations containing significant amounts of an oily component such a petroleum jelly and mineral oil. Such preparations are generally emulsions containing substantial amounts of water in addition to a detergent component. These prior art emulsion systems have the drawbacks of not only foaming poorly, but also of becoming unstable thus rendering them non-functional and cosmetically unacceptable. Some of the difficulties encountered with such prior art compositions is that high concentrations of oleaginous hydrocarbons, such as petroleum jelly and mineral oil, generally tend to suppress the foaming properties of detergents thus reducing the basic function of the detergent.

Another drawback of the above-mentioned prior art compositions is that because of the presence of water in such compositions some therapeutic agents would be rendered prematurely active in such aqueous systems so that the therapeutic potency thereof would be lost during storage.

An object of the present invention is to provide high oil containing anhydrous compositions capable of foaming when combined with water during use.

Another object of the present invention is to provide high oil containing anhydrous compositions containing a mild and gentle detergent and capable of foaming when combined with water during use so as to provide useful cosmetic, pharmaceutical and cleansing compositions.

A further object of the present invention is to provide high oil containing anhydrous compositions capable of foaming when combined with water, but which provide a useful base for agents which are normally incompatible in water-containing foaming systems.

Yet another object of the present invention is to provide cosmetically elegant anhydrous foaming cream compositions.

A still further object of the present invention is to provide high oil containing anhydrous compositions which provide a stable and functional environment for therapeutic and/or cosmetic active ingredients which are incompatible in water-containing base systems.

It is also an object of the present invention to provide therapeutic compositions employing such anhydrous base compositions

It has been found that the objects of the present invention may be realized by combining with an oily component of petroleum jelly non-modified or modified with mineral oil, a detergent which is capable of wetting out easily in high concentrations with the oily component so as to form highly useful anhydrous compositions capable of foaming when combined with water during use.

Preferably the compositions in accordance with the present invention comprise the oily component in an amount of from 20 to 50%, by weight, preferably from 30 to 50%, by weight, of the total composition, active ingredients in an amount of from 0 to 20%, by weight, additives (e.g. humectants, inert fillers and colouring agents) in an amount of from 0 to 10%, by weight, and the remainder a mild detergent, sodium cocoyl isethionate.

In accordance with the present invention, high oil systems, such as petroleum jelly or petroleum jelly modified with mineral oil, for example, may be blended with a gentle and mild detergent sodium cocoyl isethionate to produce cosmetically useful anhydrous foaming creams. When the petroleum jelly is modified with mineral oil, the mineral oil may be in an amount of up to 20%, by weight, preferably up to 15%, by weight, of the total composition.

White petrolatum which is known as petroleum jelly is a purified mixture of semi-solid hydrocarbons obtained from petroleum, chiefly of the methane series of the general formula CnH₂_n+². The white to faintly yellowish unctuous mass has a density of 0.820-0.865, a melting point of 38-54°C and a refractive index of 1.460-1.474

In the present compositions the wetting properties of sodium cocoyl isethionate with the oily component is an important factor in the results obtained. Most detergents commonly used in cleansing products, when used in high concentrations of from 30 to 50% in the oil base, do not wet out easily, but form a hard lumpy mass which is cosmetically unacceptable and non-functional when combined with water. Generally, high oil containing compositions tend to suppress the foaming properties of detergents. While the present invention is not limited to any theory of action, it appears that in the present case the combination of high amounts of oil and high amounts of the mild detergent (sodium cocoyl isethionate) overcome the foam suppressing properties of the oil so as to provide an extremely functional, stable, good foaming and cosmetically attractive product.

A most important attribute of the anhydrous composi­tions in accordance with the present invention is to provide a vehicle for active ingredients which are incompatible in aqueous systems. The present anhydrous compositions not only provide desired cleansing and foaming activity, but also allow the incorporation of active ingredients which are incompatible with water-containing cleansing composi­tions. Examples of such active ingredients include: <ul id="ul0001" list-style="none"><li>1. Benzoyl peroxide for treating acne;</li><li>2. Coal tar for treating psoriasis; and,</li><li>3. The anti-microbial combination of the magnesium sulfate adduct of 2,2ʹ-dithiobis­pyridine-1,1ʹ-dioxide and a water-soluble zinc salt (e.g. zinc chloride) disclosed in EP-A-216558 (86 306 932.4).</li></ul>

The following method may be used to produce the composition in accordance with the present invention: <ul id="ul0002" list-style="none"><li>1. Pre-melt petroleum jelly in a jacketed kettle at 70°C.</li><li>2. Add sodium cocoyl isethionate to the batch and start homogenizing at 70°C.</li><li>3. Cool the batch to 55°C and optionally add fragrance while continuing mixing.</li></ul>

Optionally, if the composition contains pigments like titanium dioxide, humectants like glycerine and/or surfac­tant foam boosters like sodium lauryl sulfoacetate, each of these components are added to the batch in step 1 before step 2 is carried out. For example, the titanium dioxide may be premixed with glycerine and added to the batch of step 1. The sodium lauryl sulfoacetate is then added to the resulting mixture with continued mixing while maintaining the temperature at 70°C. Step 2 is then carried out.

The following are specific examples of compositions formed in accordance with the present invention.

Examples 1 - 3 relate to foamable skin cleansing compositions where the remaining Examples relate to medicinal skin treating compositions.

Example 1

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Example 2

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Example 3

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Example 4

(Medicated Acne Scrub)

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Example 5

(Antimicrobial Cleanser)

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Example 6

(Psoriatic Skin Cleanser)

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