Drug – bio-affecting and body treating compositions – Dentifrices – Ammonia – amine – or derivative thereof
Reexamination Certificate
2002-07-29
2003-09-02
Rose, Shep K. (Department: 1614)
Drug, bio-affecting and body treating compositions
Dentifrices
Ammonia, amine, or derivative thereof
C424S049000
Reexamination Certificate
active
06613310
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an oral care composition which contains a bis-biguanide compound effective in the retardation of bacterial plaque accumulation on the teeth and gum diseases such as gingivitis and periodontitis. More particularly, the present invention relates to a dual component dentifrice composition of improved shelf-stability containing a bis-biguanide compound which achieves plaque and gimgivitis reduction with substantially less staining of teeth than normally occurs with bis-biguanide compound containing dentifrices and rinses.
2. The Prior Art
Dental plaque is a soft deposit which forms on teeth and is comprised of an accumulation of bacteria and bacterial by-products. Plaque adheres tenaciously at the points of irregularity or discontinuity, e.g., on rough calculus surfaces, at the gum line and the like. Besides being unsightly, plaque is implicated in the occurrence of gingivitis and other forms of periodontal disease.
A wide variety of antibacterial agents have been suggested in the art to retard plaque formation and the oral infection and dental disease associated with plaque formation. For example, bis-biguanide compounds such as chlorhexidine are well known to the art for their antibacterial activity and have been used in oral compositions to counter plaque formation by bacterial accumulation in the oral cavity. However, it is also well known that bis-biguanide compounds, when used as dental antiplaque agents cause unsightly staining of teeth. Many procedures have been proposed by the art to reduce such tooth staining: U.S. Pat. Nos. 3,925,543, 3,934,002, 3,937,807, 4,051,234, 4,080,441, 4,256,931, 4,273,759 and 4,886,658. However, the presence of bis-biguanide compounds in dentifrice compositions containing conventional ingredients such as abrasives, anionic surfactants and flavorants which are necessary for adequate cleaning and palatability of the dentifrice, these ingredients are normally incompatible with bis-biguanide compounds, and tend to diminish the bioavailability of such compounds necessary for antiplaque efficacy.
U.S. Pat. No. 5,958,381 discloses a dentifrice product capable of delivering a bis-biguanide antibacterial agent without bioavailability limitation and with limited tooth staining. U.S. Pat. No. 5,958,381 discloses a dual component bis-biguanide containing dentifrice composition in which the first component contains a bis-biguanide antibacterial agent and the second component contains an abrasive such as silica or alumina normally incompatible with the bis-biguanide. Undiminished antibacterial efficacy with minimal staining is achieved when the components which are physically separated prior to use are mixed upon tooth brushing application. However, subsequently a problem has been found to exist with the dual component composition in that the packaged dentifrice has been found to lack sufficient shelf stability for commercial acceptance.
SUMMARY OF THE INVENTION
The present invention encompasses a dual component dental composition having improved shelf stability which when applied to teeth contains a combination of a bis-biguanide compound, an abrasive and other ingredients normally incompatible with the bis-biguanide compound whereby reduction of plaque is accomplished during tooth brushing with substantially less staining of teeth that normally accompanies the use of dental compositions containing bis-biguanide compounds.
The present invention is based upon the discovery that when the separately maintained bis-biguanide compound containing dental gel component of U.S. Pat. No. 5,958,381 is prepared with a cellulose polymer thickener instead of polyoxyethylene/polyoxypropylene block copolymer as disclosed in U.S. Pat. No. 5,958,381, improved shelf stability is attained with undiminished antiplaque efficacy and limited staining when the teeth are brushed with the combined components.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the practice of the present invention the dental gel component containing the bis-biguanide ingredient is prepared using a vehicle containing a safe and effective amount of the bis-biguanide compound such as chlorhexidine in a suitable pharmaceutically acceptable vehicle in which a cellulose polymer is used as the thickening agent.
The bis-biguanide compounds useful in the practice of the present invention are known to the art and a disclosure of such compounds may be found in U.S. Pat. No. 4,886,650 (columns 2-3) which disclosure is herewith incorporated by reference. A bis-biguanide compound preferred for use in the present invention is di(N
1
,N
1
′-p-chlorophenyldiguanido-N
5
,N
5
′)hexane (chlorhexidine) and water soluble salts thereof, including the digluconate and the diacetate salts, especially the digluconate salts. Other salts include the diproponate, the diformate, the dilactate, the dihydrochloride, the dihydrofluoride, the dihydrobromide, the sulfate, the phosphate, the succinate, the pivalate, the citrate, the tartrate and the maleate. Other suitable bis-biguanide compounds include hexetidine, octenidine and alexidine.
The bis-biguanide compounds are incorporated in gel component of the present invention at about 0.001% to about 4% by weight of the gel and preferably about 2%.
The gel component prepared is using a vehicle which contains water, humectant, nonionic surfactant and thickener. The humectant is generally a mixture of humectants, such as glycerin, sorbitol and a polyethylene glycol of a molecular weight in the range of 200-1000, but other mixtures of humectants and single humectants may also be employed. The humectant content is in the range of about 10% to about 50% by weight and preferably about 10-30% by weight. The water content is in the range of about 10 to about 80% by weight.
Cellulose polymer thickeners useful in preparing a stable vehicle for the bis-biguanide containing gel component of the present invention includes hydroxyethylpropylcellulose, hydroxybutyl methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl cellulose sodium carboxymethyl cellulose. The cellulose polymer thickener may be incorporated in the gel component of the present invention at a concentration of about 1.0 to about 6% by weight and preferably about 3 to about 5% by weight.
A surfactant is incorporated in the gel component to provide foaming properties. The surfactant is preferably nonionic and is included in the gel component in amounts up to about 3% and preferably from about 0.05% to about 2% by weight of the composition.
Examples of suitable nonionic surfactants for use in the present invention include condensates of sorbitan esters of fatty acids with ehtylene oxide (polysorbates) such as sorbitan mono-oleate with from about 20 to about 60 moles of ethylene oxide. A particularly preferred polysorbate is Polysorbate 20, polyoxyethylene 20 sorbitan monolaurate.
Additional suitable nonionic surfactants useful in the present invention are the condensation products of an alpha-olefin oxide containing 10 to 20 carbon atoms, a polyhydric alcohol containing 2 to 10 carbon atoms and 2 to 6 hydroxyl groups, and either ethylene oxide or a mixture of ethylene oxide and peropylene oxide. The resultant surfactants are polymers which have a molecular weight in the range from about 400 to about 160, contain from about 40% to about 80% ethylene oxide by weight and have an alpha-olefin oxide to polyhydric alcohol mole ratio in the range from about 1:1 to about 1:3, respectively. Other nonionic surfactants useful in the present invention include condensates of sorbitan esters of fatty acids with polyethylene glycol such as sorbitan isostearate condensed with polyethylene glycol.
The paste component of the present invention in which an abrasive material is included, is generally a paste prepared using a vehicle which contains water, humectant, nonionic surfactant and thickener. The humectant is generally a mixture of humectants, such as glycerin, sorbitol and a polyethylene glycol of a molecular weight in the range of 200-1000, but
Campbell Thomas S.
Collins Michael
Nabi Nuran
Simone Alexander J.
Colgate - Palmolive Company
Rose Shep K.
Shapiro Paul
LandOfFree
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