Cosmetic and pharmaceutical foam

Abstract

The invention relates to an alcohol-free cosmetic or pharmaceutical foam carrier comprising water, a hydrophobic solvent, a foam adjuvant agent, a surface-active agent and a water gelling agent. The cosmetic or pharmaceutical foam carrier does not contain aliphatic alcohols, making it non-irritating and non-drying. The alcohol-free foam carrier is suitable for inclusion of both water-soluble and oil soluble pharmaceutical and cosmetic agents.

Description

[0001] This application claims priority to Related Applications of Israeli patent application No. 152486 filed Oct. 25, 2002 entitled “Alcohol-free Cosmetic and Pharmaceutical Foam Carrier”, and to U.S. provisional patent application No. 60 / 495,546, filed Nov. 29, 2002, entitled “Cosmetic and Pharmaceutical Foam”, which are incorporated herein in their entirety.FIELD OF THE INVENTION [0002] The invention relates to an alcohol-free, cosmetic or pharmaceutical foam carrier and its use. More specifically, the invention relates to a cosmetic or pharmaceutical foam carrier suitable for inclusion of both water soluble and oil soluble pharmaceutical and cosmetic agents. BACKGROUND OF THE INVENTION [0003] External topical administration is an important route for the administration of drugs in disease treatment. In external topical administration, the drug is absorbed into and / or through skin, mucous membrane or wound tissue. Many groups of drugs, including, for example, antibiotic, anti-fun...

AI Technical Summary

Benefits of technology

[0025] In one or more embodiments of the present invention, the alcohol-free cosmetic or pharmaceutical foamable carrier composition includes water, a liquid, non-volatile hydrophobic solvent, a foam adjuvant agent selected from the group consisting of fatty acids and fatty alcohols, a surface-active agent and a water gelling agent. Such foamable carriers, when placed in an aerosol container and combined with a liquefied gas propellant, create an oil in water emulsion, which, upon release from the aerosol container, provides a therapeutically beneficial foam product. The foam retains its structure for a time sufficient for a user to apply and to rub the foam into the skin. The foam has a very low yield strength and, hence, it breaks upon touch and makes rubbing easy and efficient, and its application even.

[0065] (6) Due to its flow properties, it spreads effectively into folds and wrinkles, providing uniform distribution of the active agent without the need of extensive rubbing and absorbs into the skin.

Problems solved by technology

However, due to the undesirable consistency of these hydrophobic carriers, their use is limited.

For instance, ointments containing white petrolatum, e.g., Vaseline petroleum jelly, as the carrier often form an impermeable barrier, so that metabolic products and excreta from the wounds to which they are applied are not easily removed or drained away.

Furthermore, it is difficult for the active drug dissolved in the carrier to pass through the white petrolatum barrier layer into the wound tissue, so the efficacy of the drug is reduced.

In addition, ointments and creams often do not create an environment for promoting respiration of the wound tissue and it is not favorable to the normal respiration of the skin.

An additional disadvantage of petroleum jelly-based products relates to the greasy feeling left following their topical application onto the skin, mucosal membranes and wounds.

Besides petroleum jelly, hydrophobic pharmaceutical carriers now in use include liquid paraffin, lanolin, beeswax, vegetable oil, glycerin monostearate, higher alcohols, polyethylene glycol and some emulsifying agents, which also have undesirable flow properties and skin feel.

Several hydrophobic liquid and semi-solid oils, e.g., mono- and poly-unsaturated oils from vegetable and marine sources, mineral oils, silicone oils, and liquid hydrophobic plant-derived oils, are known for their therapeutic benefits when applied topically, yet, their application in liquid form is not practical.

Such therapeutic oils unfortunately, cannot be applied by users in amounts sufficient to exert therapeutic affects because of they typically are liquid at use temperatures.

However, such hydrophobic solvents are difficult to formulate into a lather-producing or foam-producing product because the hydrophobic solvents interfere with the lather forming ability of the surfactant.

Furthermore, addition of oils and other emollients to topical formulations can result in an unpleasant or annoying skin residue.

Foams and, in particular, foam emulsions are complicated systems which do not form under all circumstances.

Slight shifts in foam emulsion composition, such as by the addition of active ingredients, may destabilize the foam.

Furthermore, many emulsions do not provide the high foam capacity, foam stability and / or fast-breaking action under stress or temperatures that are desired in a topical foam composition.

However, it is not obvious to produce silicone oil-based foams, since many silicone oils possess anti-foaming properties.

The alcohol promotes fast drying and thereby attempts to address the sticky feeling left by many topical formulations after application; however, alcohols, and in particular the methyl, ethyl and isopropyl alcohols preferred in the '920 patent, are defatting agents and may cause skin to become dry and cracked.

Hence, the presence of aliphatic alcohol in a therapeutic foam for external topical administration as taught in U.S. Pat. No. 6,126,920 is undesirable.

The compositions include high levels of surfactants, including ionic surfactants, and co-emulsifiers resulting in thick emulsions which are not flowable, and thus providing products which are inefficient foamers (or non-foaming) and too thick for spreading over large skin areas.

Addition of high levels of co-emulsifiers such as fatty alcohols and fatty acids suggest that the foam is not stable.

The foaming is achieved by operating a manual pump, which is not convenient for operation.

However, the patent notes that emollients and humectants interfere with the lather forming ability of the surfactant.

Apparently the foam breaks spontaneously upon discharging from an aerosol container (with no need of any rubbing or sheer force application), thus, making is impractical for spreading over a skin surface.

However, the patent fails to specify the identity or concentration of the oil component of the emulsion; and none of the compositions presented in the examples contain any oil component.

Thus, foam compositions for topical treatment, containing higher concentrations of oils, and do not comprise alcohol are still desirable.

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