This invention relates to oral care compositions providing oral and/or systemic benefits and/or composed to facilitate recovery following oral surgery. In some embodiments, the oral care compositions of the present disclosure comprise arginine or a salt thereof, and one or more zinc ion sources (e.g., zinc oxide and zinc citrate), as well as to methods of making these compositions.
Oral care compositions present particular challenges in preventing microbial contamination. Arginine and other basic amino acids have been proposed for use in oral care and are believed to have significant benefits in combating cavity formation and tooth sensitivity.
Commercially available arginine-based toothpaste for example, contains arginine bicarbonate and precipitated calcium carbonate, but not fluoride.
It has recently been recognized that oral infection (e.g., periodontitis) may affect the course and pathogenesis of a number of systemic diseases, such as endocarditis, cardiovascular disease, bacterial pneumonia, diabetes mellitus, and low birth weight. Various mechanisms linking oral infections to secondary systemic effects have been proposed, including metastatic spread of infection from the oral cavity as a result of transient bacteremia, metastatic injury from the effects of circulating oral microbial toxins, and metastatic inflammation caused by immunological injury induced by oral microorganisms. Bacterial infections of the oral cavity may affect the host's susceptibility to systemic disease in three ways: by shared risk factors; subgingival biofilms acting as reservoirs of gram-negative bacteria; and the periodontium acting as a reservoir of inflammatory mediators. Therefore, reducing the total biofilm load within the oral cavity would improve whole mouth health as well as support systemic health.
For example, a person may be particularly susceptible to deleterious effects stemming from bacterial presence within the oral cavity following dental procedures. Aside from the possibility of cross-infection within the dental facility, a patient who has undergone oral surgery oftentimes will have exposed wounds in the mouth while the treated area heals.
Certain types of bacteria known to dwell within the human oral cavity are understood to contribute to such systemic health issues. For example, Streptococcus gordonii are Gram-positive bacteria and are considered to be one of the initial colonizers of the oral cavity environment. The bacteria, along with other related oral streptococci and primary colonizing bacteria, have high affinity for molecules in the salivary pellicle coating the tooth surface therefore allowing the rapid colonization of a clean tooth surfaces. Oral streptococci ordinarily comprises the vast majority of the bacterial biofilm that forms on clean tooth surfaces. S. gordonii and related bacterial act as an attachment substrate for later colonizers of tooth surface, eventually facilitating the oral colonization of periodontal pathogens (e.g. Porphyromonas gingivitis and Fusobacterium nucleatum) via specific receptor-ligand interactions. Controlling plaque accumulation is important for gingival and oral health as well as contribute to improving the systemic well-being.
Endocarditis is an infection of the endocardium, the inner lining of the heart's chambers and valves. Endocarditis generally occurs when bacteria, fungi, or other pathogens from other body sites, including the mouth. Bacteria can infiltrate into oral tissues to reach the underlying network of blood vessels, eventually becoming systemically dispersed and colonize new sites for infection including the heart. If left unmanaged, endocarditis can lead to life-threatening complications. Treatments for endocarditis include antibiotics and, in certain cases, surgery.
Accordingly, there is a need for improved oral care compositions suitable for use in patients who are at risk for systemic bacterial infections. For example, there is a need for such oral care compositions to facilitate recovery following oral surgery, e.g., oral care compositions to reduce bacterial burden for the prevention of bacterial infections of soft tissue within the mouth of a susceptible patient population.
It has been surprisingly found that the inclusion amino acid, e.g., arginine in an oral care composition comprising a zinc oxide and/or zinc citrate, selected at certain concentrations and amounts, and a fluoride source unexpectedly increased the antibacterial effect of oral care compositions, in the oral cavity of a user. The current formulations offer the advantage of robust microbial protection without significantly interfering with the stability of the oral care composition and by allowing for formulations which allow for the integration of a basic amino acid without compromising zinc availability and deposition in situ. The increased amount of available zinc aids in reducing bacterial viability, colonization, and biofilm development. Without being bound by any theory, it is believed that the presence of the amino acid may help to increase the amount of soluble, bioavailable zinc which can then has an increased effect on inhibiting bacterial growth in the oral cavity of a user. Thus, the present compositions may be particularly useful in methods of treating or prophylaxis of gingivitis and, by relation, systemic bacterial infections stemming from oral bacteria and plaque accumulation.
Thus, in a first aspect, the present disclosure is directed to an oral care composition for use in the treatment or prophylaxis of a systemic bacterial infection consequent to promulgation of orally-derived bacteria, the oral care composition comprising a basic amino acid in free or salt from (e.g., free form arginine); and at least one zinc ion source (e.g., zinc oxide and/or zinc citrate).
In a second aspect, the present disclosure is directed to a method of treatment or prophylaxis of a systemic bacterial infection consequent to promulgation of orally-derived bacteria, the method comprising use of an oral care composition comprising a basic amino acid in free or salt from (e.g., free form arginine); and at least one zinc ion source (e.g., zinc oxide and/or zinc citrate).
Other aspects, features, benefits and advantages of the embodiments will be apparent with regard to the following description, claims and figures.
As used herein, the term “oral composition” means the total composition that is delivered to the oral surfaces. The composition is further defined as a product which, during the normal course of usage, is not, the purposes of systemic administration of particular therapeutic agents, intentionally swallowed but is rather retained in the oral cavity for a time sufficient to contact substantially all of the dental surfaces and/or oral tissues for the purposes of oral activity. Examples of such compositions include, but are not limited to, toothpaste or a dentifrice, a mouthwash or a mouth rinse, a topical oral gel, a denture cleanser, sprays, powders, strips, floss and the like.
As used herein, the term “dentifrice” means paste, gel, or liquid formulations unless otherwise specified. The dentifrice composition can be in any desired form such as deep striped, surface striped, multi-layered, having the gel surrounding the paste, or any combination thereof. Alternatively, the oral composition may be dual phase dispensed from a separated compartment dispenser.
In one aspect the invention is an oral care composition (Composition 1.0) for use in the treatment or prophylaxis of a systemic bacterial infection consequent to promulgation of orally-derived bacteria, the oral care composition comprising a basic amino acid in free or salt from (e.g., free form arginine); and at least one zinc ion source (e.g., zinc oxide and/or zinc citrate).
For example, the invention contemplates any of the following compositions (unless otherwise indicated, values are given as percentage of the overall weight of the composition):
A composition obtained or obtainable by combining the ingredients as set forth in any of the preceding compositions.
A composition for use as set forth in any of the preceding compositions. The invention further comprises the use of sodium bicarbonate, sodium methyl cocoyl taurate (tauranol), MIT, and benzyl alcohol and combinations thereof in the manufacture of a Composition of the Invention, e.g., for use in any of the indications set forth in the above method of Composition 1.0, et seq.
In a second aspect, the present disclosure is directed to a method [Method 1] of treatment or prophylaxis of a disease or disorder related to an oral and/or systemic bacterial infection consequent to promulgation of orally-derived bacteria, the method comprising the administration of an oral care composition comprising a basic amino acid in free or salt from (e.g., free form arginine); at least one zinc ion source (e.g., zinc oxide and/or zinc citrate).
For example, the invention contemplates any of the following compositions (unless otherwise indicated, values are given as percentage of the overall weight of the composition):
The disclosure further provides an oral care composition for use in a method of treatment or prophylaxis of a systemic bacterial infection consequent to promulgation of orally-derived bacteria in a subject in need thereof, e.g., for use in any of Methods 1, et seq.
The disclosure further provides the use of an oral care composition in the manufacture of a medicament for the treatment or prophylaxis of a systemic bacterial infection consequent to promulgation of orally-derived bacteria, e.g., a medicament for use in any of Methods 1, et seq.
The basic amino acids which can be used in the compositions and methods of the invention include not only naturally occurring basic amino acids, such as arginine, but also any basic amino acids having a carboxyl group and an amino group in the molecule, which are water-soluble and provide an aqueous solution with a pH of 7 or greater.
Accordingly, basic amino acids include, but are not limited to, arginine, serine, citrullene, ornithine, creatine, diaminobutanoic acid, diaminoproprionic acid, salts thereof or combinations thereof. In a particular embodiment, the basic amino acids are selected from arginine, citrullene, and ornithine.
In certain embodiments, the basic amino acid is arginine, for example, L-arginine, or a salt thereof.
The compositions of the invention are intended for topical use in the mouth and so salts for use in the present invention should be safe for such use, in the amounts and concentrations provided. Suitable salts include salts known in the art to be pharmaceutically acceptable salts are generally considered to be physiologically acceptable in the amounts and concentrations provided. Physiologically acceptable salts include those derived from pharmaceutically acceptable inorganic or organic acids or bases, for example acid addition salts formed by acids which form a physiological acceptable anion, e.g., hydrochloride or bromide salt, and base addition salts formed by bases which form a physiologically acceptable cation, for example those derived from alkali metals such as potassium and sodium or alkaline earth metals such as calcium and magnesium. Physiologically acceptable salts may be obtained using standard procedures known in the art, for example, by reacting a sufficiently basic compound such as an amine with a suitable acid affording a physiologically acceptable anion.
The oral care compositions may further include one or more fluoride ion sources, e.g., soluble fluoride salts. A wide variety of fluoride ion-yielding materials can be employed as sources of soluble fluoride in the present compositions. Examples of suitable fluoride ion-yielding materials are found in U.S. Pat. No. 3,535,421, to Briner et al.; U.S. Pat. No. 4,885,155, to Parran, Jr. et al. and U.S. Pat. No. 3,678,154, to Widder et al., each of which are incorporated herein by reference. Representative fluoride ion sources used with the present invention (e.g., Composition 1.0 et seq.) include, but are not limited to, sodium fluoride, potassium fluoride, sodium monofluorophosphate, sodium fluorosilicate, ammonium fluorosilicate, amine fluoride, ammonium fluoride, and combinations thereof. In certain embodiments the fluoride ion source includes sodium fluoride, sodium monofluorophosphate as well as mixtures thereof. Where the formulation comprises calcium salts, the fluoride salts are preferably salts wherein the fluoride is covalently bound to another atom, e.g., as in sodium monofluorophosphate, rather than merely ionically bound, e.g., as in sodium fluoride.
The invention may in some embodiments contain anionic surfactants, e.g., the Compositions of Composition 1.0, et seq., for example, water-soluble salts of higher fatty acid monoglyceride monosulfates, such as the sodium salt of the monosulfated monoglyceride of hydrogenated coconut oil fatty acids such as sodium N-methyl N-cocoyl taurate, sodium cocomo-glyceride sulfate; higher alkyl sulfates, such as sodium lauryl sulfate; higher alkyl-ether sulfates, e.g., of formula CH3(CH2)mCH2(OCH2CH2)nOSO3X, wherein m is 6-16, e.g., 10, n is 1-6, e.g., 2, 3 or 4, and X is Na or, for example sodium laureth-2 sulfate (CH3(CH2)10CH2(OCH2CH2)2OS03Na); higher alkyl aryl sulfonates such as sodium dodecyl benzene sulfonate (sodium lauryl benzene sulfonate); higher alkyl sulfoacetates, such as sodium lauryl sulfoacetate (dodecyl sodium sulfoacetate), higher fatty acid esters of 1,2 dihydroxy propane sulfonate, sulfocolaurate (N-2-ethyl laurate potassium sulfoacetamide) and sodium lauryl sarcosinate. By “higher alkyl” is meant, e.g., C6-3o alkyl. In particular embodiments, the anionic surfactant (where present) is selected from sodium lauryl sulfate and sodium ether lauryl sulfate. When present, the anionic surfactant is present in an amount which is effective, e.g., >0.001% by weight of the formulation, but not at a concentration which would be irritating to the oral tissue, e.g., 1%, and optimal concentrations depend on the particular formulation and the particular surfactant. In one embodiment, the anionic surfactant is present at from 0.03% to 5% by weight, e.g., 1.5%.
In another embodiment, cationic surfactants useful in the present invention can be broadly defined as derivatives of aliphatic quaternary ammonium compounds having one long alkyl chain containing 8 to 18 carbon atoms such as lauryl trimethylammonium chloride, cetyl pyridinium chloride, cetyl trimethylammonium bromide, di-isobutylphenoxyethyldimethylbenzylammonium chloride, coconut alkyltrimethylammonium nitrite, cetyl pyridinium fluoride, and mixtures thereof. Illustrative cationic surfactants are the quaternary ammonium fluorides described in U.S. Pat. No. 3,535,421, to Briner et al., herein incorporated by reference. Certain cationic surfactants can also act as germicides in the compositions.
Illustrative nonionic surfactants of Composition 1.0, et seq., that can be used in the compositions of the invention can be broadly defined as compounds produced by the condensation of alkylene oxide groups (hydrophilic in nature) with an organic hydrophobic compound which may be aliphatic or alkylaromatic in nature. Examples of suitable nonionic surfactants include, but are not limited to, the Pluronics, polyethylene oxide condensates of alkyl phenols, products derived from the condensation of ethylene oxide with the reaction product of propylene oxide and ethylene diamine, ethylene oxide condensates of aliphatic alcohols, long chain tertiary amine oxides, long chain tertiary phosphine oxides, long chain dialkyl sulfoxides and mixtures of such materials. In a particular embodiment, the composition of the invention comprises a nonionic surfactant selected from polaxamers (e.g., polaxamer 407), polysorbates (e.g., polysorbate 20), polyoxyl hydrogenated castor oils (e.g., polyoxyl 40 hydrogenated castor oil), betaines (such as cocamidopropylbetaine), and mixtures thereof.
Illustrative amphoteric surfactants of Composition 1.0, et seq., that can be used in the compositions of the invention include betaines (such as cocamidopropylbetaine), derivatives of aliphatic secondary and tertiary amines in which the aliphatic radical can be a straight or branched chain and wherein one of the aliphatic substituents contains about 8-18 carbon atoms and one contains an anionic water-solubilizing group (such as carboxylate, sulfonate, sulfate, phosphate or phosphonate), and mixtures of such materials.
The surfactant or mixtures of compatible surfactants can be present in the compositions of the present invention in 0.1% to 5%, in another embodiment 0.3% to 3% and in another embodiment 0.5% to 2% by weight of the total composition.
The oral care compositions of the invention may also include a flavoring agent. Flavoring agents which are used in the practice of the present invention include, but are not limited to, essential oils and various flavoring aldehydes, esters, alcohols, and similar materials, as well as sweeteners such as sodium saccharin. Examples of the essential oils include oils of spearmint, peppermint, wintergreen, sassafras, clove, sage, eucalyptus, marjoram, cinnamon, lemon, lime, grapefruit, and orange. Also useful are such chemicals as menthol, carvone, and anethole. Certain embodiments employ the oils of peppermint and spearmint.
The flavoring agent is incorporated in the oral composition at a concentration of 0.01 to 1% by weight.
The oral care compositions of the invention also may include one or more chelating agents able to complex calcium found in the cell walls of the bacteria. Binding of this calcium weakens the bacterial cell wall and augments bacterial lysis.
Another group of agents suitable for use as chelating or anti-calculus agents in the present invention are the soluble pyrophosphates. The pyrophosphate salts used in the present compositions can be any of the alkali metal pyrophosphate salts. In certain embodiments, salts include tetra alkali metal pyrophosphate, dialkali metal diacid pyrophosphate, trialkali metal monoacid pyrophosphate and mixtures thereof, wherein the alkali metals are sodium or potassium. The salts are useful in both their hydrated and unhydrated forms. An effective amount of pyrophosphate salt useful in the present composition is generally enough to provide least 0.1 wt. % pyrophosphate ions, e.g., 0.1 to 3 wt 5, e.g., 0.1 to 2 wt %, e.g., 0.1 to 1 wt %, e.g., 0.2 to 0.5 wt %. The pyrophosphates also contribute to preservation of the compositions by lowering water activity.
The oral care compositions of the invention also optionally include one or more polymers, such as polyethylene glycols, polyvinyl methyl ether maleic acid copolymers, polysaccharides (e.g., cellulose derivatives, for example carboxymethyl cellulose, or polysaccharide gums, for example xanthan gum or carrageenan gum). Acidic polymers, for example polyacrylate gels, may be provided in the form of their free acids or partially or fully neutralized water soluble alkali metal (e.g., potassium and sodium) or ammonium salts. Certain embodiments include 1:4 to 4:1 copolymers of maleic anhydride or acid with another polymerizable ethylenically unsaturated monomer, for example, methyl vinyl ether (methoxyethylene) having a molecular weight (M.W.) of about 30,000 to about 1,000,000. These copolymers are available for example as Gantrez AN 139 (M.W. 500,000), AN 1 19 (M.W. 250,000) and S-97 Pharmaceutical Grade (M.W. 70,000), of GAF Chemicals Corporation.
Other operative polymers include those such as the 1:1 copolymers of maleic anhydride with ethyl acrylate, hydroxyethyl methacrylate, N-vinyl-2-pyrollidone, or ethylene, the latter being available for example as Monsanto EMA No. 1 103, M.W. 10,000 and EMA Grade 61, and 1:1 copolymers of acrylic acid with methyl or hydroxyethyl methacrylate, methyl or ethyl acrylate, isobutyl vinyl ether or N-vinyl-2-pyrrolidone.
Suitable generally, are polymerized olefinically or ethylenically unsaturated carboxylic acids containing an activated carbon-to-carbon olefinic double bond and at least one carboxyl group, that is, an acid containing an olefinic double bond which readily functions in polymerization because of its presence in the monomer molecule either in the alpha-beta position with respect to a carboxyl group or as part of a terminal methylene grouping. Illustrative of such acids are acrylic, methacrylic, ethacrylic, alpha-chloroacrylic, crotonic, beta-acryloxy propionic, sorbic, alpha-chlorsorbic, cinnamic, beta-styrylacrylic, muconic, itaconic, citraconic, mesaconic, glutaconic, aconitic, alpha-phenylacrylic, 2-benzyl acrylic, 2-cyclohexylacrylic, angelic, umbellic, fumaric, maleic acids and anhydrides. Other different olefinic monomers copolymerizable with such carboxylic monomers include vinylacetate, vinyl chloride, dimethyl maleate and the like. Copolymers contain sufficient carboxylic salt groups for water-solubility.
A further class of polymeric agents includes a composition containing homopolymers of substituted acrylamides and/or homopolymers of unsaturated sulfonic acids and salts thereof, in particular where polymers are based on unsaturated sulfonic acids selected from acrylamidoalykane sulfonic acids such as 2-acrylamide 2 methylpropane sulfonic acid having a molecular weight of about 1,000 to about 2,000,000, described in U.S. Pat. No. 4,842,847, Jun. 27, 1989 to Zahid, incorporated herein by reference.
Another useful class of polymeric agents includes polyamino acids, particularly those containing proportions of anionic surface-active amino acids such as aspartic acid, glutamic acid and phosphoserine, as disclosed in U.S. Pat. No. 4,866,161 Sikes et al., incorporated herein by reference.
In preparing oral care compositions, it is sometimes necessary to add some thickening material to provide a desirable consistency or to stabilize or enhance the performance of the formulation. In certain embodiments, the thickening agents are carboxyvinyl polymers, carrageenan, xanthan gum, hydroxyethyl cellulose and water soluble salts of cellulose ethers such as sodium carboxymethyl cellulose and sodium carboxymethyl hydroxyethyl cellulose. Natural gums such as karaya, gum arabic, and gum tragacanth can also be incorporated. Colloidal magnesium aluminum silicate or finely divided silica can be used as component of the thickening composition to further improve the composition's texture. In certain embodiments, thickening agents in an amount of about 0.5% to about 5.0% by weight of the total composition are used.
Natural calcium carbonate is found in rocks such as chalk, limestone, marble and travertine. It is also the principle component of egg shells and the shells of mollusks. The natural calcium carbonate abrasive of the invention is typically a finely ground limestone which may optionally be refined or partially refined to remove impurities. For use in the present invention, the material has an average particle size of less than 10 microns, e.g., 3-7 microns, e.g. about 5.5 microns. For example, a small particle silica may have an average particle size (D50) of 2.5-4.5 microns. Because natural calcium carbonate may contain a high proportion of relatively large particles of not carefully controlled, which may unacceptably increase the abrasivity, preferably no more than 0.01%, preferably no more than 0.004% by weight of particles would not pass through a 325 mesh. The material has strong crystal structure, and is thus much harder and more abrasive than precipitated calcium carbonate. The tap density for the natural calcium carbonate is for example between 1 and 1.5 g/cc, e.g., about 1.2 for example about 1.19 g/cc. There are different polymorphs of natural calcium carbonate, e.g., calcite, aragonite and vaterite, calcite being preferred for purposes of this invention. An example of a commercially available product suitable for use in the present invention includes Vicron® 25-11 FG from GMZ.
Precipitated calcium carbonate is generally made by calcining limestone, to make calcium oxide (lime), which can then be converted back to calcium carbonate by reaction with carbon dioxide in water. Precipitated calcium carbonate has a different crystal structure from natural calcium carbonate. It is generally more friable and more porous, thus having lower abrasivity and higher water absorption. For use in the present invention, the particles are small, e.g., having an average particle size of 1-5 microns, and e.g., no more than 0.1%, preferably no more than 0.05% by weight of particles which would not pass through a 325 mesh. The particles may for example have a D50 of 3-6 microns, for example 3.8=4.9, e.g., about 4.3; a D50 of 1-4 microns, e.g. 2.2-2.6 microns, e.g., about 2.4 microns, and a D10 of 1-2 microns, e.g., 1.2-1.4, e.g. about 1.3 microns. The particles have relatively high water absorption, e.g., at least 25 g/100 g, e.g. 30-70 g/100 g. Examples of commercially available products suitable for use in the present invention include, for example, Carbolag® 15 Plus from Lagos Industria Quimica.
In certain embodiments the invention may comprise additional calcium-containing abrasives, for example calcium phosphate abrasive, e.g., tricalcium phosphate (Ca3(P04)2), hydroxyapatite (Ca10(P04)6(OH)2), or dicalcium phosphate dihydrate (CaHP04. 2H20, also sometimes referred to herein as DiCal) or calcium pyrophosphate, and/or silica abrasives, sodium metaphosphate, potassium metaphosphate, aluminum silicate, calcined alumina, bentonite or other siliceous materials, or combinations thereof. Any silica suitable for oral care compositions may be used, such as precipitated silicas or silica gels. For example synthetic amorphous silica. Silica may also be available as a thickening agent, e.g., particle silica. For example, the silica can also be small particle silica (e.g., Sorbosil AC43 from PQ Corporation, Warrington, United Kingdom). However the additional abrasives are preferably not present in a type or amount so as to increase the RDA of the dentifrice to levels which could damage sensitive teeth, e.g., greater than 130.
Water is present in the oral compositions of the invention. Water, employed in the preparation of commercial oral compositions should be deionized and free of organic impurities. Water commonly makes up the balance of the compositions and includes 5% to 45%, e.g., 10% to 20%, e.g., 25-35%, by weight of the oral compositions. This amount of water includes the free water which is added plus that amount which is introduced with other materials such as with sorbitol or silica or any components of the invention. The Karl Fischer method is a one measure of calculating free water.
Within certain embodiments of the oral compositions, it is also desirable to incorporate a humectant to reduce evaporation and also contribute towards preservation by lowering water activity. Certain humectants can also impart desirable sweetness or flavor to the compositions. The humectant, on a pure humectant basis, generally includes 15% to 70% in one embodiment or 30% to 65% in another embodiment by weight of the composition.
Suitable humectants include edible polyhydric alcohols such as glycerine, sorbitol, xylitol, propylene glycol as well as other polyols and mixtures of these humectants. Mixtures of glycerine and sorbitol may be used in certain embodiments as the humectant component of the compositions herein.
In some embodiments, the compositions of the present disclosure contain a buffering agent. Examples of buffering agents include anhydrous carbonates such as sodium carbonate, sesquicarbonates, bicarbonates such as sodium bicarbonate, silicates, bisulfates, phosphates (e.g., monopotassium phosphate, dipotassium phosphate, tribasic sodium phosphate, sodium tripolyphosphate, phosphoric acid), citrates (e.g. citric acid, trisodium citrate dehydrate), pyrophosphates (sodium and potassium salts) and combinations thereof. The amount of buffering agent is sufficient to provide a pH of about 5 to about 9, preferable about 6 to about 8, and more preferable about 7, when the composition is dissolved in water, a mouthrinse base, or a toothpaste base. Typical amounts of buffering agent are about 5% to about 35%, in one embodiment about 10% to about 30%, in another embodiment about 15% to about 25%, by weight of the total composition.
The present invention in its method aspect involves applying to the oral cavity a safe and effective amount of the compositions described herein.
The compositions and methods according to the invention (e.g., Composition 1.0 et seq) can be incorporated into oral compositions for the care of the mouth and teeth such as toothpastes, transparent pastes, gels, mouth rinses, sprays and chewing gum.
As used throughout, ranges are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range. In addition, all references cited herein are hereby incorporated by reference in their entireties. In the event of a conflict in a definition in the present disclosure and that of a cited reference, the present disclosure controls. It is understood that when formulations are described, they may be described in terms of their ingredients, as is common in the art, notwithstanding that these ingredients may react with one another in the actual formulation as it is made, stored and used, and such products are intended to be covered by the formulations described.
The following examples further describe and demonstrate illustrative embodiments within the scope of the present invention. The examples are given solely for illustration and are not to be construed as limitations of this invention as many variations are possible without departing from the spirit and scope thereof. Various modifications of the invention in addition to those shown and described herein should be apparent to those skilled in the art and are intended to fall within the appended claims.
The effect on zinc oxide particle charge upon exposure to amino acids was screened using zeta potential. Specific amino acids were selected based on side chain functionality: L-serine (polar, neutral), L-arginine (polar, cationic), and L-glutamic acid (polar, anionic). For zeta potential measurements, select amino acids (1.7 mmol) were added to aqueous suspensions of zinc oxide (12 mM). This concentration of zinc oxide was studied so as to minimize aggregation during zeta potential measurements. Each amino acid-zinc oxide solution was vortexed, sonicated, and then loaded into a Zetasizer DTS 1061 capillary cuvette. The cuvette was placed in the Zetasizer instrument and 12 zeta runs were performed. An average zeta potential value was calculated from the results.
To differentiate amino acid effects on zinc charge, zeta potential was used to determine the charge of zinc oxide in the presence of each amino acid (Table I). Zinc oxide alone carries a net positive surface charge at pH 8 (+16 mV). Addition of L-serine did not alter the charge, while L-glutamic acid altered zinc oxide to a net negative charge (−28 mV). Supplementation of L-arginine was shown to generate a large positive charge in solution in comparison to the other amino acids tested (+36 mV). Based on the strong positive charge of this interaction, simple aqueous solution combinations of zinc oxide and zinc citrate plus L-arginine were pursued to evaluate zinc deposition propensity on model oral surfaces.
To determine the effect of L-arginine on zinc citrate and zinc oxide in simple systems, a series of aqueous solutions of zinc citrate, zinc oxide, and L-arginine were prepared. The solids of each solution were dispersed in deionized water and followed by adjustment to pH 7.0 (±0.15) brought to a total volume of 500 mL. Zinc concentration was held constant at 100 mM through a combination of zinc citrate trihydrate (1.6 g, 2.5 mmol) and zinc oxide (3.5 g, 42.5 mmol). Three solutions were prepared by addition of L-arginine at three different levels (1.6 g, 9.2 mmol, 5.2 g, 30 mmol, and 10.5 g, 60 mmol).
HAP disks were transferred to a 24-well plate (one disk per well). Parafilm-stimulated saliva was collected from a volunteer donor, centrifuged at 8000 rpm for 10 minutes, and the supernatant filter sterilized by passing through a 0.45 um vacuum filtration device. A portion of the filtered, sterile salivary supernatant (1 mL) was added to each well. The plate was incubated at 37° C. for one hour, allowing for pellicle formation.
zinc citrate and zinc oxide formulations with and without arginine were created as below:
As shown in
Vitro Skin was cut from bulk sheets into disks 7 mm in diameter. The disks were hydrated overnight in a hydration chamber (IMS Testing Group) over a 15:85 glycerin (44 g) deionized water (256 g) solution. The Vitro Skin disks were then transferred to a 24-well plate (one disk per well). Parafilm-stimulated saliva was collected and centrifuged at 8000 rpm for 10 minutes. A portion of the salivary supernatant (1 mL) was added to each well. The plate was incubated at 37° C. for two hours on an orbital shaker, rotating at 110 rpm to allow for pellicle formation. The disks were incubated with an aliquot of the soluble fraction of each simple solution (1 mL) for two minutes. Samples of each simple solution were performed in triplicate. The simple solutions were aspirated and deionized water (1 mL) added to wash each Vitro Skin disk. Concentrated nitric acid (0.5 mL, 70%) was used to digest the sample. Upon complete dissolution of the material, samples were diluted with deionized water (4.5 mL to a total volume of 5.0 mL) for quantitative analysis by ICP-OES. As shown in
In parallel, MatTek Epigingival™ tissues (GIN-606, Ashland, Mass., USA) were treated with diluted dentifrice slurry [1 mL/tissue, 1:2 in deionized water (w/w)] for two minutes at room temperature. Tissues were washed with phosphate-buffered saline (PBS, 2 mL) three times and transferred into fresh tubes, one tissue per tube. Tissues were digested with nitric acid (70%, 0.5 mL) at room temperature overnight. Digested samples were diluted with deionized water (4.5 mL to a total volume of 5.0 mL), followed by centrifugation of the tubes at 4000 rpm for ten minutes. The supernatant of each sample was transferred into a fresh tube for analysis with ICP-OES.
Dentifrice prototypes containing both zinc citrate and zinc oxide with or without L-arginine as described in Example 2 were designed to be tested on the Epigingival tissue samples. These formulas were evaluated against a commercial fluoride toothpaste for zinc deposition and antibacterial efficacy in an EpiGingival tissue model comprised of oral epithelial cells of human origin. The commercial toothpaste was formulated as follows:
As shown in
To determine the amount of zinc delivered to biofilms as a function of dentifrice product, salivary biofilms were grown on vertically suspended HAP disks for 48 hours at 37° C. under a 5% CO2 environment. Biofilm culture consisted of McBain medium [2.0 g/L BactoPeptone (Difco, Detroit, Mich., USA), 2.0 g/L Trypticase Peptone (BD, Franklin Lakes, N.J. USA), 1.0 g/L yeast extract (BD), 0.35 g/L sodium chloride (Sigma-Aldrich, St. Louis, Mo., USA), 0.2 g/L potassium chloride, 0.2 g/L calcium chloride, 2.5 g/L mucin, and 50 mmol/L PIPES, (pH=7.0)] supplemented with 5 μg/mL hemin and 1 μg/mL menadione. The medium was refreshed a total of four times at approximately 12-hour intervals. Each biofilm was then treated once with an aliquot of dentifrice slurry diluted in sterile deionized water [1.5 mL, 1:2 (w/w)] for two minutes. The dentifrice slurry was aspirated and the biofilm washed twice in sterile deionized water for five minutes. The treated biofilms were transferred into sterile deionized water (700 L) by sonication using a Virtis virsonic 600 (80% power for two minutes per disk side at 30-second intervals). Nitric acid (0.5 mL, 70%) was added to each treated biofilm sample and left to digest overnight. Upon complete dissolution of the material, samples were diluted with deionized water (to a total volume of 5.0 mL) for quantitative analysis by ICP-OES.
Dentifrice prototypes containing both zinc citrate and zinc oxide with or without L-arginine were designed to be evaluated against a commercial fluoride toothpaste for zinc deposition and antibacterial efficacy in static human saliva-derived bacterial biofilms. As shown in
The effect of the test dentifrices on bacterial metabolic function was evaluated through measurement of bacterial respiration and extracellular acidification rates. Multispecies oral biofilms from an unbrushed saliva inoculum were cultured vertically on HAP disks in McBain media supplemented with 5 μg/mL hemin, 1 μg/mL menadione, and 0.2% sucrose at 37° C. for 48 hours under an environment containing 5% CO2. Resulting biofilms were harvested in water by vigorous pipetting. The dislodged bacteria were reconstituted into fresh 0.25× media [tryptic soy broth (TSB)+0.2% sucrose], and the bacterial suspension adjusted to a final optical density (OD) of approximately 0.7 (610 nm). An aliquot of the diluted bacterial suspension (10 L), the diluted toothpaste slurry [12 L, 1:10, (w/w)], and media (180 L) were added to XF Cell Culture Microplates pre-coated with Corning Cell Tak. The resulting reaction mixture was then centrifuged for 10 minutes at 1500×g at room temperature. Real-time oxygen consumption rates (OCR) and extracellular acidification rates (ECAR) for multi-species bacteria derived from biofilms were determined using the Seahorse Extracellular Flux (XF24) analyzer (Seahorse Bioscience, MA, USA). The microplate was loaded to the analyzer measuring changes in OCR and ECAR over 50 cycles (4.5 hours) in response to treatment. The area under the curve (AUC) was calculated for all 50 cycles upon completion of the assay using SciDavis software. Experimental replicates corresponded to biofilms derived from new saliva donors.
The results are summarized as follows in Table 1:
Referring to
To prepare the anaerobic bacterial model, whole saliva was harvested from a total of four volunteers and pooled for a single inoculum. The OD of the inoculum was adjusted to an absorbance of approximately 0.3 (610 nm). Sterile HAP disks were incubated for 24 hours at 37° C. under anaerobic conditions in sterile artificial saliva containing 0.01% sucrose (1 mL) and pooled saliva (1 mL) in a 24-well plate. Disks were treated with a 1:2 (w/w) slurry of diluted dentifrice in water for 10 minutes and then transferred into sterile artificial saliva (2 mL). Disks were treated once per day for a total of eight days. At days two, four, and eight, the disks were collected and transferred to 0.5× pre-reduced thioglycolate medium. Samples were diluted and plated on Neomycin-Vancomycin (NV) agar to quantify total Gram-negative anaerobes. Plates were incubated anaerobically at 37° C. for 72 hours before determining total colony counts. Results are reported as log (CFU/mL) for triplicate samples.
In parallel, in order to test the effect of the test dentifrices on bacterial growth in aerobic biofilm model, whole saliva was pooled from three volunteers and centrifuged for 10 minutes at 8000 rpm. The supernatant was collected and sterilized by UV light and filtered. An aliquot of sterilized human salivary supernatant (1.5 mL) was transferred to each well of a 24-well sterile culture plate. HAP disks held in a vertical position by a modified steel lid were suspended in the saliva and incubated for one hour at 37° C. to allow a pellicle to form.
Aliquots of diluted dentifrice slurry in deionized water [1.5 mL, 1:3 (w/w)] were placed in the appropriate wells of a sterile 24-well plate. Pellicle-coated disks were transferred to this plate and incubated for two minutes at room temperature with vigorous shaking on an orbital shaker. Following treatment, the HAP disks were rinsed two times for five minutes each in a plate containing fresh, sterile 0.25×TSB (1.5 mL/well) with the same vigorous shaking. HAP disks were then transferred to a plate containing SHI medium (Teknova) with 25% whole saliva from a single donor and incubated (37° C., 5% CO2) for four hours to allow for initial colonization to occur. Following incubation, a second treatment was performed in the same manner as previously described. HAP disks were transferred to a plate containing sterile SHI medium with no further inoculum applied to the experiment. For four subsequent days, the plates were removed at 24-hour intervals from the initial treatment and treated again, as above.
Following the sixth and final treatment, the disks were incubated for an additional two to three hours to allow the bacteria to recover. Disks were then transferred to individual 15 mL round bottom test tubes containing 0.25% trypsin solution in water (2 mL). HAP disks were incubated in trypsin at 37° C. for one hour to remove the biofilm from the disks. Following trypsinization, biofilm bacteria were quantified for viability remaining after treatment. Bacteria samples were diluted and plated on blood agar to quantify for total aerobic bacteria. Plates were incubated aerobically at 37° C. for 24-48 hours before determining total colony counts. Results are reported as log (CFU/mL) for triplicate samples.
As shown in
Zinc penetration and retention in salivary biofilms were evaluated using a laboratory model with a continuous media flow. Sterile HAP-coated glass microscope slides were pre-incubated with individually collected saliva inoculum containing saliva and plaque-derived bacteria for two hours at 37° C. under an environment containing 5% CO2. The inoculated slides were then transferred into a drip-flow biofilm reactor (Biosurface Technologies Corporation, Bozeman, Mont., USA) and incubated at 37° C. The biofilms were cultured under a constant flow rate of 10 mL/hour of growth medium consisting of 0.55 g/L proteose peptone (BD), 0.29 g/L trypticase peptone, 0.15 g/L potassium chloride (Sigma-Aldrich, St. Louis, Mo., USA), 0.029 g/L cysteine-HCL, 0.29 g/L yeast extract, 1.46 g/L dextrose, and 0.72 g/L mucin. The medium was supplemented with sodium lactate (0.024%, final concentration) and hemin (0.0016 mg/mL, final concentration). The biofilms were cultured for a total of 10 days. The resulting biofilms were then treated with dentifrice slurry diluted in sterile deionized water [1:2 (w/w)] for two minutes. Following treatment, the biofilms were washed twice in sterile deionized water (five-minute intervals) and then placed back into the biofilm reactors, resuming biofilm culture as previously described. The treated biofilms were allowed to recover for approximately 12 hours. The resultant biofilms were harvested by flash-freezing in liquid nitrogen and excised from the glass slides while carefully maintaining their orientation.
The biofilms were stored at −80° C. until analyzed by imaging mass spectroscopy. Biofilm samples were analyzed by Protea Biosciences (Morgantown, W. Va., USA) using Bruker UltrafleXtreme MALDI TOF/TOF. The biofilms were cryosectioned at 16 μm thickness and placed on stainless steel MALDI targets. The biofilms were coated with sinapinic acid (10 mg/mL, at a flow rate of 30 μL/min for a total of 30 coats) and allowed to dry for 20 seconds prior to analysis. The biofilm samples were ablated at 200 laser shots per pixel at a spatial resolution of 50 μm using reflectron positive ion mode. Sample mass ranges of between 100-1000 Daltons were collected and the images visualized using Bruker Flex Imaging.
A concentration map analysis of the resulting MALDI-MS image is shown in
The effect of the test dentifrice treatment in limiting bacterial adhesion was determined in vitro on gingival epithelial cells. Gingival epithelial cells were collected from three volunteer donors using a sterile cotton swab with gentle scraping along the gum area. The collected cells were resuspended in sterile PBS (4 mL) and enriched via centrifugation at 8000 rpm for ten minutes. The resulting cellular pellet was resuspended in PBS (400 μL). The isolated gingival epithelial cells were treated with diluted dentifrice slurry [5 μL, 1:10 in water (w/w)] for approximately two minutes. The treated cells were collected via centrifugation at 8000 rpm for 10 minutes and resuspended in Hanks Balanced Salt Solution (HBSS, 1 mL). The resulting cells were then challenged as described below with Streptococcus gordonii DL-1 endogenously expressing mCherry (created as described by Aspiras M B, et al. Expression of green fluorescent protein in Streptococcus gordonii DL1 and its use as a species-specific marker in coadhesion with Streptococcus oralis in saliva-conditioned biofilms in vitro. Appl Environ Microbiol 2000; 66:4074-83).
S. gordonii were cultured in Brain Heart Infusion broth supplemented with erythromycin [5 μg/mL, (final concentration)] and cultured at 37° C. under 5% CO2 environment for 48 hours. Prior to challenge, the bacterial culture was resuspended separately in HBSS to a final optical density of 0.1 (610 nm). An aliquot of the bacterial suspension (100 μL) was then added to the treated epithelial cells and co-incubated in a 37° C. orbital shaker for two hours at 80 rpm. Non-adherent cells were removed by centrifugation at 1000 rpm for five minutes and the cell pellet resuspended in HBSS. The cells were washed a total of three times. Following the wash steps, the cell pellet was resuspended in ProLong Gold DAPI (100 μL), and mounted on glass slides. The samples were visualized by confocal microscopy using Nikon C2siR (Melville, N.Y., USA) under 40× magnification. The samples were imaged using solid state lasers at 405 nm and 561 nm to detect DAPI and mCherry. DiC images were collected using a 488 nm laser. Z-plane scans from 0-30 μm were collected with a total of three to four randomly chosen z-stack images per treatment per volunteer sample (n=3).
In vitro multimodal assessment of the zinc citrate, zinc oxide and arginine dentifrice mechanism of action was also determined through inhibition of bacterial colonization on soft tissue surfaces. Confocal imaging of bacteria-challenged cheek cells treated with the zinc citrate, zinc oxide and arginine dentifrice showed less bacteria adherent per gingival cell as compared with cells treated with only a regular fluoride toothpaste (
While the present invention has been described with reference to embodiments, it will be understood by those skilled in the art that various modifications and variations may be made therein without departing from the scope of the present invention as defined by the appended claims.
Number | Date | Country | |
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62785032 | Dec 2018 | US |