Drug – bio-affecting and body treating compositions – Dentifrices
Reexamination Certificate
2000-02-18
2001-10-23
Rose, Shep K. (Department: 1614)
Drug, bio-affecting and body treating compositions
Dentifrices
C424S618000, C423S118100, C428S323000
Reexamination Certificate
active
06306371
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to storage stable antiplaque oral composition containing a silver zeolite compound which exhibits antibacterial efficacy against plaque causing oral bacteria.
2. The Prior Art
Dental plaque is a soft deposit which forms on teeth as opposed to calculus which is a hard calcified deposit on teeth. Unlike calculus, plaque may form on any part of the tooth surface, particularly at the gingival margin. Hence, beside being unsightly, it is implicated in the occurrence of gingivitis.
It is difficult to predict the efficacy of antibacterial agents when incorporated in oral compositions. For example, cationic antibacterial materials such as chlorhexidine, benzthonium chloride and cetyl pyridinium chloride have been used by the art as antibacterial antiplaque agents in oral compositions. However, such agents are generally not effective when there is also present anionic surfactants which surfactants are required for the effective performance of oral compositions such as toothpaste. Nonionic antibacterial materials are compatible with anionic ingredients in oral compositions and nonionic halogenated hydroxydiphenyl ethers such as Triclosan have been effectively employed in oral compositions as antiplaque agents when admixed with neutral materials such as humectants, abrasives and thickeners used in the formulation of oral compositions. Notwithstanding the antiplaque efficacy of Triclosan, there is a continuing interest in the oral composition field for such agents which are compatible with anionic surfactants present in such compositions.
Silver zeolite, is an antibacterial a compound used in products such as toothbrushes, clothing, medical devices, and kitchen cleaners. One main disadvantage of silver zeolite is that it causes discoloration (yellowing/browning) when present in products which are exposed to the environment. In dental products which contain silver zeolite, the silver ion is easily oxidized when exposed to air and light at room and elevated temperatures and forms a discolored precipate in the presence of anionic surfactants such as sodium lauryl sulfate (SLS) which substantially diminishes the acceptability of the product consumers.
Various means have been proposed by the art to overcome the discoloration problem have significant disadvantages. The silver zeolite containing product can be placed in air-tight and non-transparent packaging. This is not practical for most products because of cost constraints. Attempts to eliminate the presence of anionic surfactants such as SLS on toothpaste products is not practical as such elimination materially degrades the foaming and cleaning functionality of the product. Attempts to add colors and pigments such as titanium dioxide to mask the discoloration has limited success due to the continued presence of discoloration or “dulling” effects caused by the oxidation of silver ion.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided an antiplaque oral composition comprising an orally acceptable vehicle, an effective antiplaque amount of silver zeolite and a stabilizing amount of a soluble chloride, acetate or citrate salt. As will hereinafter be disclosed by the addition of low concentrations of salts such as sodium chloride a dentifrice can be formulated with both sodium lauryl sulfate and silver zeolite which does not undergo discoloration when exposed to environmental conditions. The dentifrice will not brown over a period of time at both room and accelerated temperature. In addition, direct air an sunlight exposure have no discoloration effect on the dentifrice.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Silver zeolite compounds useful in the practice of the present invention are known to the art and are more fully describe in U.S. Pat. No. 4,938,958, U.S. Pat. No. 4,911,898, U.S. Pat. No. 4,775,585 and U.S. Pat. No. 4,525,410. The silver zeolite compounds are natural or synthetic zeolite particles retaining silver metal ions at the ion-exchangeable sites thereof. The silver ion is present in the zeolite typically at a concentration of about 0.2 to about 2.5% by weight and preferably about 0.3 to about 1% by weight.
Zeolite is generally aluminosilicate having a three-dimensionally grown skeleton structure and is generally shown by X
2
O—Na
2
O—Al
2
O
3
-2SiO
2
·ZH
2
O, wherein X represents an ion-exchangeable metal ion, which is usually the ion of a monovalent or divalent metal; n corresponds to the valence of the metal; and Z is the number of water of crystallization. Various kinds of zeolites having different component ratio, fine pore diameter, and specific surface area are known and are available commercially.
As an example of the prior art concerning bactericidal silver zeolite compounds, U.S. Pat. No. 4,911,898 discloses bactericidal zeolite particle retaining silver metal ions having bactericidal properties at ion-exchangeable sites of the zeolite. The silver zeolite compound is prepared by contacting the zeolite with a solution of a water soluble silver salt, the silver ion of which has bactericidal properties thereby exchanging with the silver ion from the solution, the a concentration of the silver salt in the solution being sufficiently low to prevent deposition of silver compounds onto the zeolite and wherein the contacting is repeated until a substantial amount of the ion exchange capacity of the zeolite is reached.
Examples of water soluble salts which will impart color stabilization to oral compositions containing silver zeolite compounds include water soluble chloride salts such a sodium chloride, calcium chloride, potassium chloride, zinc chloride and strontium chloride and salts that combine with silver (ion) to form low water soluble salts such as acetates and citrates as for example calcium acetate and potassium and sodium citrate.
Salts that have been found not to be effective as color stabilizing agents are those that release anions that will combine with silver cations to form bromide, carbonate, oxide, phosphate and nitrate salts.
The silver zeolite compound is incorporated in oral compositions of the present invention in a non-toxic, effective antiplaque amount, typically in a range of about 0.5 to about 5% and preferably about 2.0 to about 4.0% by weight whereby 0.03 to about 3% by weight and preferably 0.3 to about 1% by weight silver ion is released by the silver zeolite compound. The color stabilizing salt is incorporated in the oral composition at a concentration of about 0.03 to about 3% and preferably 0.1 to about 1% by weight.
Surfactants are used in the compositions of the present invention to achieve increased prophylactic action and assist in achieving thorough and complete dispersion of the oral composition ingredients and are present in the oral composition at a concentration of about 0.5 to about 5% by weight and preferably about 1 to about 30% by weight throughout the oral cavity. The surfactant material is preferably anionic, suitable examples which include water-soluble salts of higher fatty acid monoglyceride monosulfates, such as the sodium salt of the monosulfated monoglyceride of hydrogenated coconut oil fatty acids, higher alkyl sulfates such as sodium lauryl sulfate, alkyl aryl sulfonates such as sodium dodecyl benzene sulfonate, higher alkyl sulfoacetates, higher fatty acid esters of 1,2-dihydroxy propane sulfonate, and the substantially saturated higher aliphatic acyl amides of lower aliphatic amino carboxylic acid compounds, such as those having 12 to 16 carbons in the fatty acid, alkyl or acyl radicals and alkoyl taurines, and the like. Examples of the last mentioned amides and taurates are N-lauroyl sarcosine, and the sodium, potassium and ethanolamine salts of N-lauroyl, N-myristoyl, or N-palmitoyl sarcosine which should be substantially free from soap or similar higher fatty acid material as well as N-methyl-N-cocoyl (or oleoyl or palmitoyl) taurines.
Linear molecularly dehydrated polyphosphate salts can be optionally employed herein as anticalculus agents in the
Brahms John C.
Nabi Nuran
Patel Suryakant
Sreenivassan Prem
Wong Mike
Colgate-Palmolive Company
Rose Shep K.
Shapiro Paul
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