Drug – bio-affecting and body treating compositions – Dentifrices
Reexamination Certificate
2002-12-30
2003-12-30
Rose, Shep K. (Department: 1614)
Drug, bio-affecting and body treating compositions
Dentifrices
Reexamination Certificate
active
06669929
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a dentifrice and more particularly to a dentifrice containing rapidly water hydratable film flakes suspended in the dentifrice composition which impart to the dentifrice decorative, cosmetic and therapeutic benefits.
2. The Prior Art
Aesthetic effects have been acknowledged to play an important role in consumer acceptance of many products. In many cases ornamental effects have been used to distinguish particular products in the marketplace and identify products having particular distinct properties. In the dentifrice field, substantially clear dentifrice products such as toothpastes and gels which have incorporated therein contrasting colored flakes are known. Such flakes provide an aesthetic effect which the consumer finds pleasing and promotes the use of the dentifrice, particularly by children. Although such products have met with consumer approval, the art seeks to further improve the aesthetic effects as well as the cosmetic and therapeutic benefits of these products so as to encourage the use of dentifrices in practicing oral hygiene.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a dentifrice having suspended therein flakes of a water hydratable film (hereinafter film flakes) comprised of a homogeneous mixture of a water soluble hydroxyalkyl cellulose polymer and starch, the film matrix having entrained therein an agent selected from therapeutic, cosmetic and decorative agents.
In one embodiment of the invention there is provided an aesthetically decorative dentifrice having distributed throughout film flakes in which a decorative colorant is entrained in the film matrix, the dentifrice vehicle being substantially clear so that the aesthetically decorative effect can be viewed by the user.
In a second embodiment, therapeutic agents such as antibacterial agents and fluoride anticaries salts, are entrained in the film flake matrix.
In a third embodiment cosmetic agents such as sweetening agents, breath freshening agents, are entrained in the film flake matrix which flavorants are rapidly released as the flakes disintegrate during toothbrushing, delivering a pleasing burst of sweetness or breath freshening flavor into the oral cavity.
The entrainment of the therapeutic and cosmetic agents in the film flake matrix suspended in the dentifrice isolates these agents from interaction with reactive ingredients present in the dentifrice so that the agents are maintained substantially separate from the reactive dentifrice ingredients during manufacture and storage while subsequently being released from the film matrix when the dentifrice containing the film flakes is topically applied to the tooth surface as by tooth brushing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The term “substantially clear” when used in to describe the present invention shall mean translucent or transparent. The term “dentifrice” shall include toothpastes and gels.
The Film Flakes
The film flakes of the present invention are formed from a matrix comprised of hydroxyalkyl methylcellulose starch and starch film forming agents in which is entrained a colorant such a dye or pigment, a flavorant, sweetener and/or a therapeutic agent such as an antibacterial agent or a breath freshening agent. The film matrix can further comprise water, additional film forming agents, plasticizing agents, surfactants and emulsifying agents.
Preparation of Film Matrix
In preparing the film matrix according to the present invention the hydroxyalkylmethyl cellulose, a starch ingredient, a colorant, flavor, sweetener and/or therapeutic agents and other film forming ingredients are dissolved in a compatible solvent to form a film forming composition. The film forming composition is cast on a releasable carrier and dried to form a sheet of film matrix material. The carrier material must have a surface tension which allows the film solution to spread evenly across the intended carrier width without soaking to form a destructive bond between the film carrier substrates. Examples of suitable carrier materials include glass, stainless steel, Teflon and polyethylene-impregnated paper. Drying of the film may be carried out at high temperature using a drying oven, drying terminal, vacuum drier, or any other suitable drying equipment which does not adversely effect the ingredients of which the film is composed.
The film thickness ranges in size from 0.5 to 10 microns and preferably 2 to 3 microns. The dried film of the present invention is then cut or punched into shaped flakes having a particle size of 0.01 to 0.50 inches preferably 0.08 to 0.25 inches.
Additional stability can be provided to the shapes formed from the dried film, by applying to the film, before shaping into flakes, a protective barrier overcoat such as a food grade shellac or ethyl cellulose.
When the film is to be used for decorative effect, the film once formed is punched into various attractive shaped flakes such as hearts, stars, diamonds and circles. The film flakes are incorporated in the base dentifrice of the present invention at a concentration of about 0.05 to 1.0% by weight and preferably 0.1 to about 0.5% by weight.
Film Forming Agents
The major film forming agent used to prepare the film matrix of the present invention is an hydroxyalkyl cellulose such as hydroxypropyl methyl cellulose, hydroxyethylpropyl cellulose, hydroxybutyl methyl cellulose, hydroxy propyl methyl cellulose and carboxymethyl cellulose. Preferably the cellulose polymer is a low viscosity hydropropylmethyl cellulose polymer (HPMC). When HPMC is used as the film forming agent it is preferred that the HPMC have a viscosity in the range of about 1 to about 40 millipascal seconds (mPa.s) as determined as a 2% by weight aqueous solution of the HPMC at 20° C. using a Ubbelohde tube viscometer. Preferably the HPMC has a viscosity of about 3 to about 20 mPa.s at 20° C.
HPMC is available commercially from the Dow Chemical Company under the trade designation Methocel E5 LV. Methocel E5 LV is a USP grade, low viscosity HPMC having 29.1% methoxyl groups and 9% hydroxyproxyl group substitution. It is a white or off-white free-flowing dry powder. As a 2 wt. % solution in water as measured with a Ubbelohde tube viscometer it has a viscosity of 5.1 mPa.s at 20° C.
The hydroxyalkyl methyl cellulose is incorporated in the film matrix in amounts ranging from about 10 to about 60% by weight and preferably about 15 to about 40% by weight.
Cold water swellable, physically modified and pregelatenized starches are particularly useful as texture modifier to increase the stiffness of the hydroxyalkyl methyl cellulose film matrix of the present invention. In the preparation of such starch products, the granular starch is cooked in the presence of water and possibly an organic solvent at a temperature not higher than 10° C. higher than the gelatinization temperature. The obtained starch is then dried.
Pregelatinized corn starch is available commercially. A preferred starch is available under the trade designation Cerestar Polar Tex-Instant 12640 from the Cerestar Company. This Cerestar starch is a pregelaterized, stabilized and crosslinked waxy maize starch. It is readily dispersible and swellable in cold water. In its dry form, it is a white free flowing powder with an average flake size no greater than 180 micrometers and 85% of the flakes are smaller than 75 micrometers. It has a bulk density of 44 lbs/ft
3
.
The Cerestar starch has excellent cold storage and freeze-thaw stability. It has a rapid hydration rate and can reach extremely high viscosity without cooking. It has a smooth and creamy texture similar to cook-up starches. It also has excellent paste clarity and a bland flavor.
The pregelatinized starch is present in the film matrix of the present invention in an amount ranging from about 5 to about 50% by weight and preferably about 10 to about 35% by weight.
The hydroxyalkyl cellulose to starch ratio (by weight) may vary from about 1:3 to about 4:1 and preferably about 1:1.5 to about 2.5:1.
Dec
Boyd Thomas J.
Carale M. Teresa R.
Xu Guofeng
Colgate - Palmolive Company
Lieberman Bernard
Rose Shep K.
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