United States Patent:  6,086,856

Assignee:  OralCare Systems, Inc. (Virginia Beach, VA)

Filed:  September 19, 1995

Oral hygiene formulations comprising foaming surfactants are dispensed in the form of foams by means of an air-driven propellantless dispenser. The formulations comprise mouthwashes, rinses and dentifrices containing one or more antimicrobial anti-plaque and anti-cariogenic agents.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an oral hygiene system useful in the treatment and prevention of tooth decay, gingivitis and periodontal disease comprising a gas-driven foam dispenser housing a foamable aqueous oral hygiene formulation and a foam-producing gas comprising molecular oxygen, said gas being substantially free of CFC and hydrocarbon propellants.

In one aspect, the invention provides a personal self-administrable mouth care system wherein the foam dispenser is air-driven, that is, the foam-producing gas consists essentially of air and the foam produced is an aerated foam. Preferably, in this embodiment, the foam dispenser comprises a reversibly compressible and decompressible container housing, at substantially atmospheric pressure, said air and a foamable aqueous (including aqueous alcoholic) mouthcare formulation comprising one or more oral components and an orally-acceptable (hereinafter oral) surfactant as a foaming aid.

In another aspect, the invention provides an oral hygiene system for professional use wherein the foam dispenser is driven by a molecular oxygen-containing gas comprising from about 50 to 100 volume percent of molecular oxygen and from about 50 to 0 volume percent of an inert environmentally-acceptable and nonflammable gas, such as nitrogen, helium, argon, neon, carbon dioxide and mixtures of any two or more thereof.

In yet another aspect, the invention provides new, foamable mouthcare formulations, including mouthwashes, rinses and dentrifices as new compositions of matter that are foamable with air or other molecular-oxygen-containing gas.

In a further aspect, the invention comprises a process for treating the oral cavity with a mouthcare formulation, which comprises:

1. Bringing together, in foam-producing proportions, in a mixing zone,

a. an aqueous mouthcare formulation containing a compatible oral surfactant in an effective foam-producing amount, and

b. an oxygen-containing gas essentially free of environmentally-objectionable CFCs and flammable hydrocarbons;

2. causing said (a) and (b) components to mix such that they form an oxygenated (e.g. aerated) foam; and

3. Allowing the foam to be dispensed from the mixing zone, preferably directly into the oral cavity to be treated.

The mixing zone is conveniently the mixing chamber of a propellantless dispenser, more preferably such a device as described hereinafter.

Preferably, the formulation is non-ingestible and meant to be expectorated, the foaming gas is air, the surfactant is anionic, more preferably sodium lauryl sulfate (SLS).

It has been found that the delivery of oral hygiene components to the oral cavity in the form of a flowable foam improves the effervescence of the formulation and, in turn, improves the removal of tissue and other debris. The formulation is particularly well suited to suspend and foam away food particles and other debris, and then itself be rinsed away quickly.

The system of the present invention is capable of producing dramatic and rapid detergent action in order to instantly provide voluminous quantities of microbubbles from relatively small initial volumes of formulation. This detergent action, in turn, greatly facilitates the effectiveness of the formulation as an oral rinse. The invention system, for instance, can rapidly provide a volume of bubbles from about 2 grams of formulation that is as great or greater than the volume obtained by swirling up to an ounce (e.g., about 25-30 grams) of a commercial mouthwash in the mouth for 30 seconds, as recommended by the manufacturer.

The invention delivery system for mouthcare formulations may be a propellantless dispenser of the squeeze bottle variety. Such dispenser provides numerous advantages over the art, including simplicity, safety, efficiency and economy of operation. The foams are flowable and readily generated; for example, in the personal mouthcare embodiment, simply by squeezing the container and directing the resulting foam into the oral cavity as it is being dispensed for intimate contact with the oral target surfaces. The foam's effectiveness is aided by swishing the foam around in the mouth so that it can penetrate the interproximal spaces between adjacent teeth and between teeth and gums. In being foamed, the liquid formulation is transformed into an aerated low density mass comprising a multitude of bubbles comprising gas-supported thin-walled liquid films having a high surface area to liquid volume ratio. The foam thus presents a high concentration of actives at (or close to) the surface of the film for direct surface-to-surface contact with the target areas of the oral cavity. It is conjectured that actives leaving the surface of the film and adhering to the surface of the oral target are readily replaced at the surface, in view of the high surface area available, by diffusion of actives from within the liquid film to the surface thereof. Thus, the total amount of the liquid formulation needed for effective treatment may be greatly reduced, providing thereby economy at operation.

Further, since the aerated foams present a smaller total quantity of ingredients in the mouth at any one time during a given treatment period, and since many of the ingredients are harmful if ingested, the treatment with foam is inherently more safe than treatment with slugs of bulk liquid, in the event some of the material is inadvertently swallowed and ingested. It is recognized that swirling bulk liquid around in the mouth for 30 to 60 seconds may, in some cases, result in some foaming, however, the extent of such foaming is substantially less than that produced and provided in accordance with the compositional requirements and the method of this invention.

Also, in utilizing air or other molecular oxygen-containing gas, the invention treatment avoids the hazards, environmental objections and costs entailed in aerosol use of flammable hydrocarbons and environmentally-objectionable halocarbon propellants.

A further advantage is that the molecular oxygen-containing gas (supporting the liquid film of active ingredients of the foam) is also in position to contact the target surfaces of the oral cavity, in particular the gums. For example, by diffusion into and through the film or by breakdown of the bubbles under the swirling action of the mouth, the gas is available as a bactericide, alone or in conjunction with other antimicrobials normally present in the formulation.

The ratio of gas to liquid in the foams as dispensed can vary widely depending largely on (a) the surface tension of the liquid, which is a function of the surfactant it contains and its concentration (b) the actives and their concentrations in the liquid and (c) the desired effect. The gas/liquid ratio is conveniently expressed in terms of the relative densities of the foam (foamed liquid) and the bulk (unfoamed) liquid since the density of the foam is essentially determined by the weight of the liquid therein. In other words, the gas-liquid composition of the foam can be controlled by means of the surfactant to produce oral dosages that contain relatively small weight fractions of the liquid. Taking the density of the liquid equal to 1, typical such relative density fractions are in the range of from about 1/3 to 1/20 preferably 1/4 to 1/10. With such low usage of liquid in the foam, dosing the oral cavity may be repeated one or more times as needed to achieve a desired effect and still maintain a savings in liquid (i.e. actives) usage.

Claim 1 of 24 Claims

1. A self-administrable oral hygiene system comprising an air-driven foam dispenser comprising a reversibly compressible and decompressible container housing separate volumes of

(i) a foamable aqueous mouthwash comprising one or more compatible foam-promoting oral surfactants and, in effective hygienic amounts, at least one agent selected from the group consisting of an oral antimicrobial agent, an anti-plaque agent, an anticariogenic agent and mixtures thereof, said agent being soluble or dispersible in water or water containing up to about 25% of ethanol and,

(ii) a foam-producing amount of air.

____________________________________________
If you want to learn more about this patent, please go directly to the U.S. Patent and Trademark Office Web site to access the full patent.