FIELD OF INVENTION:

The present invention relates to a stable dentrifice composition, and more particularly, relates to said composition favouring improved availability of the actives including potassium ion in the oral cavity from its freely soluble salt form when present in combination with selective anionic surfactants belonging to the class of long chain olefin sulfonates for effective treatment of dental hypersensitivity yet retaining the sensorial properties of foam in terms of both quality and quantity as desired of such compositions.

Most importantly, the said composition also beneficially aids in incorporating higher levels of oral care actives and surfactants at orally acceptable levels and in an orally acceptable silica/ chalk based formulation without affecting but retaining the sensorial properties of foaming both in terms of quality and quantity and also without adversely affecting the after taste of said composition. Advantageously thus, the dentifrice composition of the present invention involving a soluble potassium salt with or without other orally useful actives in combination with a selective anionic surfactant thus enhances the availability of the actives especially potassium salt thereby making the dentifrice composition therapeutically more beneficial to the users having excellent foam characteristics & good foam stability in a suitable orally acceptable vehicle.

BACKGROUND ART:

Oral compositions such as toothpastes, gels & mouthwashes are basically designed for cleansing the oral cavity as well as loosening & removing plaque and also providing malodor control. Apart from these basic functional benefits, specific oral compositions are also designed to control gingivitis, tartar, tooth decay, sensitive tooth-to name a few oral conditions.

Dental plaque is a soft deposit which occurs in the form of a thin film on all dental surfaces. It is comprised of an accumulation of bacteria & bacterial by-products. The danger associated with plaque on teeth lies in its tendency to eventually cause gingivitis, periodontitis & other types of periodontal diseases such as dental caries (tooth decay) & dental calculus (tartar).

Use of fluoride in oral care products have been shown to be beneficial in preventing dental caries. Use of Zinc salts is also known to have anti-plaque activity & is found to be beneficial in preventing gingivitis.
Dentine hypersensitivity is sensation felt when the nerves inside the dentine of the teeth are exposed to the environment. The sensation can range from irritation all the way to intense, shooting pain. This sensitivity can be caused by several factors, including wear, decaying teeth or exposed tooth roots.
Dentine contains many thousands of microscopic tubular structures that radiate outwards from the pulp; these dentinal tubules are typically 0.5-2 micrometers in diameter. Changes in the flow of the plasma-like biological fluid present in the dentinal tubules can trigger mechanoreceptors present on nerves located at the pulpal aspect thereby eliciting a pain response. This hydrodynamic flow can be increased by cold, air pressure, drying, sugar, sour (dehydrating chemicals), or forces acting onto the tooth. Hot or cold food or drinks, and physical pressure are typical triggers in those individuals with teeth sensitivity.

Treatment can consist of amorphous calcium and phosphate, Bioactive glass, Potassium nitrate, strontium chloride, gluma, fluoride therapy, calcium sodium phosphosilicate & the like. The mode of action is linked to their ability to form mineralized deposits within the tubule lumen and on the surface of the exposed dentine that help prevent transmission of the applied stimulus.

Surfactants are used in oral compositions to achieve increased prophylactic actions & render the dentrifice more cosmetically acceptable. The surfactant is preferably a detersive material which imparts detersive & foaming properties to the oral composition. Usually Sodium lauryl sulfate (SLS) is used as detergent in dentrifices.

Sodium alkyl sulfate surfactants, e.g., SLS, generally have compatibility issues with compounds that contain potassium because an insoluble potassium alkyl sulfate precipitate forms when the sodium alkyl sulfate is combined with a potassium salt (Patent reference USP7435409). While the solubility of SLS in water is about 10% on a gram per gram basis, experiments indicate that the solubility of potassium lauryl sulfate is less than approximately 0.02%. Due to precipitate formation, it has been observed that dentrifices for treatment of hypersensitivity with potassium nitrate containing SLS as detergent have inadequate foaming & inadequate soluble potassium available for treatment of dental hypersensitivity. Inadequate foam generation while brushing, is undesirable to consumers. Also, since the potassium salt is being occupied in the insoluble potassium lauryl sulfate precipitate, usefulness of potassium salt in the composition is not optimized.

Use of anioninc surfactants like sodium lauryl sarcosinate, sodium methyl cocoyl taurate; nonionic surfactants; Amphoteric surfactants like Coco Amido Propyl Betaine is known to be used as alternate for SLS. However, some of them seriously affect after taste of the toothpaste, or it may be inadequate in removing dental plaque or such involvement of additional surfactants may be detrimental and add on to the cost.

EP 0 422 803 A2 (Alexander et al., 1990) describes an anionic free dentrifice composition having combination of nonionic, cationic or amphoteric surfactant to accommodate a cationic antibacterial agent and does not specify the use of any anti-hypersensitive material.

EP 0 278 744 A2 (Caserio et al., 1988) relates to a dentrifice composition comprising a synergistic composition of potassium ions and 2, 4, 4' - trichloro-2' 2 hydroxyphenyl ether for treatment for sensitive teeth and also uses SLS as the surfactant.

EP 0 390 456 A2 (Jackson et al., 1990) describes an oral hygiene composition comprising a water soluble strontium salt and a water soluble potassium salt together in suitable ratios, with a dentally acceptable excipient for treatment of dental hypersensitivity. Preferred surfactants used in the invention are low ionic materials such as Sodium N-methyl - N - cocoyl taurate or nonionic materials like condensates of propylene glycol and polyethoxylated hydrogenated castor oil. Other suitable surfactants include water soluble salts of higher fatty acid monoglyceride monosulphates (e.g., sodium hydrogenated coconut fatty acid monoglyceride monosulfate); higher alkyl sulfates (e.g., sodium lauryl sulfate); alkylarylsulfonates (e.g., sodium dodecylbenezenesulfonates); and higher alkyl sulfoacetates (e.g., sodium lauryl sulfoacetate); saturated higher aliphatic acyl amides of lower aliphatic amino carboxylic acids having 12 to 16 carbon atoms in the acyl radical and in which the amino acid portion is derived from the lower aliphatic saturated monoaminocarboxylic acids having 2 to 6 carbon atoms, such as the fatty acid amides of glycine, sarcosine, alanine, 3-aminopropionoc acid and valine, particularly the N-lauroyl, myristoyl and palmitoyl sarcosinate compounds.

US patent 5,690,911 (Mirajkar et al., 1997) describes a combination of anionic & nonionic surfactant system with an amount of halogenated diphenyl ether or phenolic antibacterial compound, present at weight ratios effective to increase the delivery & uptake of antibacterial compound to oral surfaces so as to enhance the therapeutic efficacy wherein the anionic surfactant used is SLS and also teaches the incorporation of ingredients for treatment of dental hypersensitivity such as potassium nitrate & potassium citrate. However, they teach that incorporation of such ingredients are made in amounts which do not substantially adversely affect the properties and characteristics desired that goes to indicate that such ingredients cannot be possibly added in doses to be effective, but is only limited by its presence that would not 'substantially' affect the properties of the dentrifice.

US patent 5,849,267 (Collins et al., 1998) describes a desensitizing anti tartar dentrifice with desirable cream or gel consistency, retaining phase integrity with polyphosphate or phosphono compound anti-tartar agent and potassium salt for sensitive teeth with alkali metal carboxymethyl cellulose and xanthan gum as gelling agents. Surfactants employed in the composition is preferably anionic, nonionic or ampholytic in nature, most preferably anionic. Suitable anionic surfactants are higher alkyl sulfates such as sodium or potassium lauryl sulfate, higher fatty acid monoglyceride monosulphates (e.g., potassium salt of the monosulfated monoglyceride of hydrogenated coconut oil fatty acid); alkyl aryl sulfonates (e.g., potassium dodecylbenezenesulfonates); higher fatty sulfoacetates; higher fatty acid esters of 1,3-dihydroxy propate sulfonate, and the substantially saturated higher aliphatic acyl amides of lower aliphatic amino carboxylic acids having 12 to 16 carbon atoms in the acyl radicals, and the like.

US patent 6,180,089 (Gambogi et al., 2001) discloses a two component dental composition, used for dentinal hypersensitivity, which comprises a first dentrifice component having an alkaline pH and a second dentrifice component having an acid pH and atleast one of the components contains a potassium ion releasable compound, the first and second components being maintained separate from each other until dispensed wherein the surface active material taught is anionic or nonionic in nature and wherein the anionic surfactants include higher alkyl sulfates such as sodium or potassium lauryl sulfate which is preferred; higher fatty acid monoglyceride monosulphates (e.g., salt of the monosulfated monoglyceride of hydrogenated coconut oil fatty acid); alkyl aryl sulfonates (e.g., Sodium dodecylbenezenesulfonates); higher fatty sulfoacetates; higher fatty acid esters of 1,3-dihydroxy propate sulfonate.

US patent 6,464,963 (Gambogi et al., 2002) describes a two component desensitizing dentrifice composition, which comprises a first dentifrice component containing potassium salt and an alkali metal compound such as NaOH and a second dentifrice component containing a desensitizing stannous salt source the first and second dentifrice components being maintained separate from each other until dispensed for application to teeth, which is to prevent interaction of stannous salt with NaOH to form Sn(OH). The surface active material disclosed is preferably anionic or nonionic in nature. Anionic surfactants include higher alkyl sulfates such as sodium or potassium lauryl sulfate which is preferred; higher fatty acid monoglyceride monosulphates (e.g., salt of the monosulfated monoglyceride of hydrogenated coconut oil fatty acid); alkyl aryl sulfonates (e.g., Sodium dodecylbenezenesulfonates); higher fatty sulfoacetates; higher fatty acid esters of 1,3-dihydroxy propate sulfonate.

US patent 7,435,409 (Nelson et al., 2008) describes an oral composition comprising an effective amount of soluble potassium salt, a sodium (C8-C24) alkylsulfate in an effective amount and an orally acceptable polar surfactant, comprising a hydrophobic portion selected from a (C6-C30) alkyl group and a polymeric silicone group wherein the molar ratio of the surfactant to the sodium (C8-C24) alkylsulfate is greater than or equal to about 1:1. This prior art provides a method for inhibiting the formation of potassium lauryl sulfate precipitate in an aqueous composition comprising a soluble potassium salt and a sodium (C8-C24) alkylsulfate along with a polar surfactant in an amount equal to or greater than the amount of sodium (C8-C24) alkylsulfate in the composition.

None of the above prior arts are found to involve the olefin sulfonates in their dental compositions however, US patent 3,462,525, (Levinsky et al., 1969) discloses a dental composition with long chain olefin sulfonates as an alternate detergent to SLS, which has good taste & free of undesirable 'orange juice' flavor reaction, non irritating to the oral mucosal layer & exhibits good foaming characteristics. Ingredients in the compositions include abrasives (both silica & chalk), humectants, binders and gelling agents including water insoluble dental polishing material such as sodium metaphosphate, potassium metaphosphate, tricalcium phosphate, dehydrated dicalcium phosphates etc. and wherein the olefin sulfonate contain olefinic group of 8-25 carbon atoms and is present between 0.1% - 7% in the composition to improve the taste profile of the dentrifice without affecting other characteristics.

Therefore Alpha Olefin Sulfonate (AOS) as disclosed in this prior art is present in combination with an insoluble salt of potassium that acts as a dental polishing material in the dental composition wherein AOS simply enhances the taste of the prior composition and is thus not directed to render maximum availability of potassium ions in the oral cavity from a soluble potassium salt present in combination for effective treatment of dental hypersensitivity.

Hence as apparent from the abovesaid, though there exists various dentifrice compositions, no such compositions have been made available in the art that are directed to render maximum availability of potassium and surfactant activity in the oral cavity from its soluble salt when present in combination for effective treatment of dental hypersensitivity by retaining the sensorial properties of foam in terms of quantity and quality.
Hence, there is a longfelt need in the art to provide for an effective dentifrice composition which while on one hand would be effective for the treatment of dentine hypersensitivity due to the maximum availability of the actives in the oral cavity, such as potassium ions, and on the other, would also beneficially aid in incorporating higher levels of oral care actives and with maximum surfactant activity at orally acceptable levels and in an orally acceptable vehicle due to its maximum availability without affecting but retaining the sensorial properties of foam both in terms of quality and quantity to thus have excellent foam characteristics & good foam stability without affecting or altering the after taste of the toothpaste.

OBJECTS OF THE INVENTION

It is thus a basic object of the present invention to provide for an oral composition preferably a stable dentrifice composition with actives containing soluble potassium salt for the treatment of dental hypersensitivity in combination with a selective anioinic surfactant belonging to the class of long chain olefin sulfonates to favour improved availability of the actives such as potassium ions in the oral cavity.
Another object of the present invention is to provide for said selective anionic surfactant based stable dentifrice composition involving soluble potassium salt as actives for the treatment of dental hypersensitivity that would possess excellent foam characteristics & good foam stability due to miximal available surfactant activity.

Yet another object of the present invention is to provide for said selective anionic surfactant based stable dentifrice composition involving said actives for the treatment of dental hypersensitivity that would retain sensorial properties of foaming both in terms of quality and quantity with maximal surfactant activity to thus have excellent foam characteristics & good foam stability in an orally acceptable vehicle and also without affecting or altering the after taste of the dentrifrice.

Still another object of the present invention is to provide for a stable dentrifice composition with said improved availability of said actives in the oral cavity thereby making said dentifrice composition therapeutically more beneficial to the users that would also possess excellent sensorial foaming both in terms of quality and quantity.

Yet another object of the present invention is to provide for said stable dentifrice composition that would beneficially aid in incorporating higher levels of said oral care actives and selective surfactants at orally acceptable levels also in orally acceptable vehicle in a formulation due to said improved availability of the actives and surfactants.

Another aspect of the present invention is to provide for the said dentifrice composition that would enable effective control of the dosage levels of said actives present in the said composition due to its maximum availability in the oral cavity

such as to be present at therapeutic levels without affecting the properties of the dentifrice.

SUMMARY OF THE INVENTION

Thus according to the basic aspect of the present invention there is provided a stable dentrifice composition comprising

a. A soluble potassium salt in effective amounts;

b. Eeffective amounts of selective anionic surfactants belonging to the class of long
chain olefin sulfonates;

c. Optionally, with or without other orally useful actives in an orally acceptable
vehicle; favouring availability of potassium ions in the oral cavity from its freely
soluble salt form benefitting treatment of dental hypersensitivity with favourable
foam characteristics & stability.

Surprisingly, it is thus found by way of the present invention that a stable dentifrice composition for effective treatment of dental hypersensitivity could be attained when said composition comprises soluble potassium salt as the active present in combination with selective anionic surfactants belonging to the class of long chain olefin sulfonates wherein maximum availability of potassium ions are rendered in the oral cavity from its freely soluble salt form due to the presence of said selective anionic surfactants whereby the sensorial properties of foaming in terms of quality and quantity is also retained by said composition. The said improved availability of potassium ions in the oral cavity are not affected by other ingredients in said composition that may be present in combination with or without other orally useful actives selected from fluoride ions, zinc salts, antimicrobial agents and the like. Moreover, in addition to the improved availability of potassium ions from its freely soluble salt form, the foam and surfactant activity in the said composition are effectively retained in an orally acceptable vehicle, and wherein said composition also beneficially aids in incorporating higher levels of above oral care actives and surfactant at orally acceptable levels and in a orally acceptable vehicle due to said maximum availability of the actives.

In another preferred aspect of the present invention there is provided said stable dentrifice composition wherein the preferable long chain olefin sulfonates as the selective anioinic surfactants are (alpha) olefin sulfonates (AOS).

Advantageously the selective AOS also possesses a set of properties which makes it suitable for the dental composition of the present invention. It exhibits good wetting and foaming properties, excellent detergency, and good resistance to water hardness ions, good mildness properties, low oral and dermal toxicity and ease of biodegradability.

In yet another preferred aspect of the present invention there is provided said stable dentrifice composition wherein said long chain olefin sulfonates are preferably with olefinic group of 8 - 25 carbon atoms more preferably, (alpha) olefin sulfonates (AOS) with olefinic group of 12-21 carbon atoms and their soluble salts like Sodium (alpha) Olefin sulfonate, Potassium (alpha) olefin sulfonate and the like; wherein the concentration of AOS is from about 0.01 % to 20 %, preferably from, about 0.1 % to 10 %; more preferably from 0.5 % to 5 % in the said composition.

In another preferred aspect of the present invention there is provided said stable dentrifice composition wherein said effective amount of soluble potassium salt is preferably selected from potassium nitrate, potassium citrate, potassium chloride, potassium oxalate, potassium bicarbonate, potassium phosphate, dibasic potassium phosphate, tribasic potassium phosphate, and potassium pyrophosphate salts such as dipotassium pyrophosphate, tetra potassium pyrophosphate, tripotassium pyrophosphate, & monopotassium pyrophosphate or mixures thereof.

In yet another preferred aspect of the present invention there is provided said stable dentrifice composition wherein said soluble potassium salt is preferably potassium nitrate in amounts of 0.01% by weight to about 20 % by weight; preferably from about 0.1 % by weight to about 10 % by weight & more preferably from about 0.1 % by weight to about 5% by weight of the composition.
In another preferred aspect of the present invention there is provided said stable dentrifice composition wherein said orally acceptable vehicle includes water, alcohol, humectants selected from glycerin, sorbitol, xylitol, propylene glycol and / or

Polyethylene Glycol, or suitable mixtures thereof. The concentration of oral acceptable vehicle may be in amounts of about 1% to about 99.9% by weight of the oral composition.

In yet another preferred aspect of the present invention there is provided said stable dentifrice composition wherein said stable dentifrice composition is selected from Toothpaste or Dental Cream or gel, Mouthwash or Mouth rinse, tooth powder, Chewing gum, freshness candy, dental floss adapted for cleaning oral cavity and to maintain oral hygiene.

In another aspect of the present invention there is provided a device for oral care comprising means for containing said stable dentrifice composition and means for selectively dispensing the same for oral care.

BRIEF DESCRIPTION OF FIGURES:

Figure 1: Available Potassium in presence of AOS & SLS; Figure 2: Drop in Potassium activity over 3 months time

DETAILED DESCRIPTION OF THE INVENTION:

As discussed hereinbefore the present invention provides for an oral care composition comprising a soluble potassium salt as active in combination with suitable anionic surfactant belonging to the class of long chain olefin sulfonates with olefinic group of 8-25 carbon atoms, more preferentially (alpha) olefin sulfonates (AOS) and their soluble salts like but not limited to Sodium (alpha) Olefin sulfonate,

Potassium (alpha) olefin sulfonate with or without other orally useful actives like fluoride ions, zinc salts, antimicrobial agents with excellent foam characteristics & good foam stability in an orally acceptable vehicle. Advantageously, said oral care composition preferably a stable dentifrice composition ensures maximum availability of potassium ions for dental hypersensitivity from its freely soluble salt form when present in combination with said selective surfactants in order to provide for a therapeutically effective composition. More advantageously, the dentifrice composition of the present invention enables effective control of the dosage levels of the actives present in the said composition due to its maximum availability of said actives in the oral cavity thereby allowing the actives to be present at therapeutic levels in the composition without affecting the properties of the dentifrice, most advantageously, the dentifrice composition of present invention ensures maximum retention of surfactant activity in the composition due to the inability of AOS to form a complex with potassium slats, there by making AOS and Potassium salts available in a soluble state in the system.

For the purpose of better appreciation of the invention reference is made to various terms as detailed here under:

As used here in, the term "Dentifrice" is intended to describe compositions for oral care or dental care applications that could be a cleaning device or a material that cleans oral cavity to keep a good oral hygiene, in general a dentifrice could be but not limited to Toothpaste or Dental Cream or gel, Mouthwash or Mouth rinse, Tooth powder, Chewing gum, freshness candy, dental floss etc.
Except where other wise explicitly indicated, all numbers in this description indicating amounts of materials or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". All amounts are by weight of the composition, unless other wise specified.

The term "oral care" used here in includes the teeth, tongue, lips, buccal cavity and oral mucousa
Preferred cosmetic compositions are those suitable for application on the teeth, oral mucousa and buccal cavity to maintain good oral hygiene.

Detergents

Detergents are generally used in dental preparations to help clean teeth, oral cavity & provide good foam that helps to carry away debris. Usually anionic surfactants which include long chains fatty or poly-lower alkoxy groups plus hydrophilic radicals are used. They will usually be in the form of salts, especially water soluble salts of alkali metals. Useful anionic surfactants include the higher fatty acid monoglyceride monosulfates, such as monosulfated monoglycerides of hydrogenated coconut oil fatty acid; higher alkyl sulfates, such as sodium lauryl sulfate (SLS); alkyl aryl

sulfonates, such as sodium linear dodecyl benzene sulfonate; higher olefin sulfonates, such as sodium olefin sulfonate in which the olefin group is 12 to 21 carbon atoms; higher alkyl alkali sulfoacetates such as sodium lauryl sulfoacetate; higher fatty acid esters of 1,2 -dihydroxypropane sulfonates; the substantially saturated higher aliphatic acyl amides of lower aliphatic aminocarboxylic acid alkali metal salts, such as those having 12 to 16 carbon atoms in the fatty acyl radicals; higher alkyl poly-lower alkoxy (of 10 to 100 alkoxies) sodium sulfates; higher fatty acid sodium & potassium soaps of coconut oil and
tallow and the like.

The composition of the present invention specifically comprises suitable anionic surfactant preferentially long chain Olefin sulfonates with olefinic group of 8 - 25 carbon atoms, more preferentially (alpha) olefin sulfonate (AOS) with olefinic group of 12 - 21 carbon atoms wherein the concentration of AOS is from about 0.01 % to 20 %, preferably from about 0.1 % to 10 %; more preferably from 0.5 % to 5 %.

Active Ingredients

The composition of the present invention may comprise of one or more active ingredients. The term 'active ingredient' refers to, unless otherwise specified, any substance that possesses a therapeutic, hygienic or cosmetic activity or possesses an activity that enhances the aesthetic or sensory properties of the composition.

Specific example of orally acceptable active ingredients comprises a soluble potassium salt. A 'soluble potassium salt', for purposes of this application and unless otherwise indicated, is any potassium salt that is soluble in an aqueous solution. Preferably the soluble potassium salt is any potassium salt that has a solubility of greater than or equal to about 5% in water.
The active ingredient is present in the compositions of the present invention in an 'effective amount', which means that the ingredient i.e. soluble potassium salt, is present in the composition in an amount that is atleast sufficient to provide the activity for which the potassium salt has been selected. An effective amount can be determined by one with skill in the art. Generally the amount of soluble potassium ion effective for oral care compositions is from about 0.001% to about 2%.

Some specific examples of orally acceptable, soluble potassium salts that can be used as an active ingredient in the oral composition of the present invention for reducing dentin hypersensitivity include but not limited to potassium nitrate, potassium citrate, potassium chloride, potassium oxalate, potassium bicarbonate, potassium phosphate, dibasic potassium phosphate, tribasic potassium phosphate, and potassium pyrophosphate salts such as dipotassium pyrophosphate, tetrapotassium pyrophosphate, tripotassium pyrophosphate, & monopotassium pyrophosphate. Pyrophosphate salts have activity as detergent builders and thus useful in removing plaque & / or stains present on dental surfaces. Mixtures of such salts can also be used in the present invention.

In a preferred embodiment, the potassium salt capable of reducing dentin hypersensitivity is potassium nitrate. The amount of the soluble potassium salt ranges preferably from about 0.01% by weight to about 20 % by weight; preferably from about 0.1 % by weight to about 10 % by weight & more preferably from about 0.1 % by weight to about 5% by weight of the composition.
The oral composition of the present invention may also contain a source of fluoride ions or fluorine - providing component, as anticaries agent in an amount sufficient to supply about 1 ppm to 1500 ppm of fluoride ions or a therapeutically effective dosage & include inorganic fluoride salts such as soluble alkali metal salts. For example fluoride sources used in the composition of the present invention are sodium fluoride, potassium fluoride, sodium fluorosilicate, sodium monoflurophosphate (SMFP), ammonium fluorosilicate, stannous fluoride and the like. Sodium fluoride or SMFP are preferred fluoride compounds.

The amount of sodium fluoride in the present invention ranges from 0.001% by weight to about 1% by weight; preferably from about 0.01% by weight to about 0.5% by weight; and more preferably from about 0.1% by weight to about 0.36% by weight of the composition. The amount of sodium monofluorophosphate (SMFP) in the present invention ranges from 0.001% by weight to about 3 % by weight; preferably from about 0.01% by weight to about 2 % by weight; and more preferably from about 0.1 % by weight to about 1.2% by weight of the composition.

Another active ingredient in the dentrifice composition of the present invention are antimicrobial agents. Such useful antimicrobial agents include non-cationic antimicrobial agents which are based on phenolic or bisphenolic compounds such as halogenated diphenyl ethers such as Triclosan (2,4,4' - trichloro -2 -hydroxydiphenyl ether), methylparaben, propylparaben, butylparaben, bronopol, sodium benzoate, Potassium sorbate and the like.

The amount of antimicrobial agents like Triclosan in the composition of the present invention may range from about 0.001 % by weight to about 1 % by weight; preferably from about 0.01 % by weight to about 0.5 % by weight; more preferably from about 0.01 % by weight to about 0.3% by weight of the composition.

Other active ingredient may also include zinc salts with anti tartar or anti-calculus benefits such as Zinc chloride, zinc acetate, zinc sulfate, zinc oxide and the like.
Zinc salts like Zinc sulfate in the composition of the present invention may range from about 0.001 % by weight to about 10% by weight; preferably from about 0.01 % by weight to about 5% by weight; more preferably from about 0.1 % by weight to about 1 % by weight of the composition.
Orally acceptable Vehicle

Orally acceptable vehicles are used to prepare dentrifice composition which includes water, alcohol, humectants and bulking agents. The hconcentration of the vehicle typically totals from about 1% to about 99% by weight, preferably from about 5% to 95% by weight and more preferably from about 10% to 90% by weight of the composition.

The alcohol used may be, but not limited to ethyl alcohol with or without denaturant as may be required.

The humectants preferably used may be, but not limited to glycerin, sorbitol, xylitol, propylene glycol and / or Polyethylene Glycol, but other humectants & mixtures thereof may also be employed. Humectants present in the dentifrice may be in an amounts of about 1% to about 99% by weight, preferably by about 2% by weight to about 90% by weight, more preferably by about 5% by weight to about 60% by weight of the composition.
Bulking agents

Bulking agents are generally used in the dentifrice compositions to give mass to the composition and are generally having abrasive or polishing or mechanical cleaning properties. Calcium carbonate, silica and aluminum silicate and the like are used as bulking agents with or with out water and other orally acceptable vehicle.
Abrasives

Abrasives used may include silica abrasives such as but not limited to precipitated or hydrated or colloidal or fumed silica and the like generally having a mean particle size of upto about 20 microns. Other polishing agents which may be employed, including water insoluble sodium metaphospho silicia gel, potassium metaphosphate, tricalcium phosphate, calcium phosphate dihydrate, anhydrous dicalcium phosphate, calcium pyrophosphate magnesium orthophosphate, trimagnesium phosphate, calcium carbonate, alumina trihydrate, aluminum silicate, zirconium silicate, calcined alumina, bentonite, and complex amorphous alkali metal aluminosilicates, and mixtures thereof.
Preferred abrasive materials in the preparation of dentrifice composition of the present invention, for oral dentifrice formulations, include silica gels and precipitated amorphous silica. These silicas are colloidal particles having an average particle size ranging from about 3 microns to about 12 microns; and preferably between about 5 micron to about 10 microns and a pH range from 4 to 10, preferably 6 to 9 when measured as a 5% by weight slurry.

The preferred abrasives in the composition of present invention may be silica or calcium carbonate, whose concentrations in the composition may range from about 1% by weight to about 99% weight, preferably from 2% to 80% by weight and more preferably from 3% to 70% by weight.

Thickening & Binding agents

Thickeners or binders are used in oral composition to have a preferred rheologicai and viscosity profiles. Thickeners and binders used in the composition of the present invention include natural and synthetic gums and colloids. Thickeners used in the composition may include xanthan gum, polyethyleneglycols, cellulose gum, carragennan gum, silica which function as as thickening or binding agent such as hydrated silica, precipitated silica, colloidal silica and the like, inorganic thickeners including natural and synthetic clays, lithium magnesium silicate, magnesium aluminum silicate, and mixtures thereof.
Thickening agent is present in the dentrifice of the current invention in amounts of about 0.01% to about 25% by weight, preferably by about 0.05% by weight to about 15% by weight, more preferably by about 0.1% by weight to about 10% by weight of the composition.
Flavor

The oral composition of the present invention may also contain a flavoring agent. These may include synthetically made flavor oils or natural derived essential oils. Example of essential oils include but not limited to spearmint, peppermint, wintergreen, clove, sage, eucalyptus, marjoram, cinnamon, lemon, lime, grapefruit, orange and the like. The flavoring agent incorporated in the composition at a concentration of aboutO.001% to about 5 % by weight, preferably 0.01% by weight to about 2.5 % by weight and more prefarably 0.1 % by weight to about 1.5% by weight of the composition.
Herbal actives

Herbal actives or mixtures can be used to give additional benefits. They include, but not limited to materials like Neem, Tulsi, Ginger, Clove, Amla and the like and their mixtures thereof. Herbal actives incorporated in the composition ranges from about 0.001% to about 10% by weight, preferably by about 0.01% by weight to about 5% by weight, more preferably by about 0.05% by weight to about 1% by weight of the composition.

Various other materials may be incorporated in the dentrifice composition of the present invention like whitening agents such as hydrogen peroxide, calcium peroxide and urea peroxide; coloring agents, chelating agents like EDTA; synthetic or artificial sweeteners like Sodium saccharine, aspartame, acesulfame potassium; opacifiers like Titanium dioxide, Zinc oxide, and the like. These additives, when present, are incorporated in the oral compositions of the present invention in amounts which do not substantially adversely affect the properties and characteristics desired.

The present invention is explained hereunder in greater details in relation to the non-limiting exemplery and comparative illustrations. The following examples further describe and demonstrate preferred embodiments within the scope of the present invention. The examples are solely for illustration and are not to be construed as a limitation of this invention as many variations thereof are possible without departing from its spirit and scope.

Table 1 is a comparative study between long chain olefin sulfonates (preferably AOS) and SLS present in combination with a soluble potassium salt. While the use of AOS clearly allows maximum potassium ion availability in the oral cavity from its freely soluble form present in combination, it is also observed that AOS in combination retains the surfactant activity while SLS does not, due to complexation with potassium ion in the combination. Additional advantages such as the generation of good foam height, good foam stability, foam quality, taste were effectively retained at a reduced cost thereby making the composition attractive to the end users.

Table 1: Comparative study between AOS and SLS

Table 2 & 3 illustrates increasing doses of SLS does not help in improving surfactant activity as they are continuously used up for complexing with freely available potassium ions.

Table 2: Physical observation of SLS & AOS at different doses with and without KN03

PREPARATION OF ORAL CARE COMPOSITIONS

Tooth paste - General Process of preparation of toothpaste or Gel:

Step1: Aqueous Phase: take in main mixing vessel; Water, Sorbitol, Sodium
Saccharin, Potassium nitrate, Zinc sulfate, Sodium fluoride in the main mixing vessel
and start mixing. Ensure all the solids are completely dissolved.

Step2: Gum premix: Mix separately Titanium dioxide, Abrasive silica, Thickening
silica and binders and transfer to the main mixing vessel under mixing.

Step3: Mix separately Triclosan in Flavour, add to the main mixing vessel

Step4: Add AOS to the main mixing vessel and ensure maximum mixing.

Step5: Remove the entrapped air by applying vacuum.
Mouth wash - General process of Preparation:

Step1: Aqueous Phase - Take Water in the main mixing tank, add Sodium fluoride,
Potassium Nitrate, Sodium Saccharin and Bronopol, ensure solids are dissolved.

Step2: Add Sorbitol to the main mixing tank.

Step3: Mix separately Flavour and Denatured Alcohol and add to main mixing tank.

Step4: Add Polysorbate 20 to the main mixing tank under mixing till a clear solution
is obtained.

Step5: Add AOS, mix under low speed mixing.

Example 1: Typical SLS toothpaste composition

Ingredient SLS Toothpaste

%w/w
Water 36.68
Sorbitol 32.00
Sodium CMC 0.80
Thickening silica 10.00
Abrassive silica 10.00
KN03 5.00
NaF 0.22
Zinc sulfate 0.20
Sodium saccharin 0.30
Titanium Dioxide 0.50
SLS 3.00
Triclosan 0.30
Flavor 1.00
21

Example 2A: Typical examples of dentifrice of the present invention

Ingredient Toothpaste - Silica Based (%w/w)

A B C D E F G H I J K
Water 36.68 37.98 36.63 36.58 36.53 42.83 42.33 41.83 41.83 42.12 40.12
Sorbitol 32.00 32.00 32.00 32.00 32.00 25.00 25.00 25.00 25.00 25.00 25.00
Glycerin 5.00 5.00 5.00 5.00 5.00 5.00
PEG 600 1.00 1.00 1.00 1.00 1.00 1.00
Xanthan gum 0.10 0.10 0.10 0.10 0.10 0.10
Sodium CMC 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80
Thickening silica 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00
Abrassive silica 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00
TSPP 0.50 0.50 0.50 0.50 0.50 0.50
KN03 5.00 5.00 5.00 0.50 0.50 0.50 0.50 0.10 0.10
KCI 3.70
Potassium Citrate 5.05
NaF 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.33 0.33
ZnCI 0.25
ZnS04 0.20 0.20 0.20
Zinc Citrate 0.30
Sodium Saccharin 0.30 0.30 0.30 0.30 0.30 0.25 0.25 0.25 0.25 0.25 0.25
Ti02 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50
AOS 3.00 3.00 3.00 3.00 3.00 2.00 2.50 3.00 3.00 3.00 5.00
Triclosan 0.30 0.30 0.30 0.30 0.30 0.3 0.3 0.3 0.3 0.3 0.3
Flavor 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
22

Example 2B: Typical examples of dentifrice of the present invention

Ingredient Toothpaste - Chalk based (% w/w) Toothpaste -Gel based (% w/w) Toothpowder (% w/w) Mouthwash (% w/w)

L M N O P Q
Water 19.36 19.11 16.85 17.19 73.87
Sorbitol 20.00 20.00 45.00 45.00 12.00
Glycerin 7.00 7.00 5.00 5.00
PEG 600 2.00 2.00
PEG 1500 1.30 1.30
Tween 20 2.20
Denatured alcohol 6.00
Sodium CMC 0.78 0.78 0.45 0.45
Thickening silica 4.50 4.50 4.00 4.00 2.00
Abrassive silica 18.00 18.00 10.00
CaC03 36.00 36.00 78.99
KN03 5.00 5.00 5.00 5.00 5.00 5.00
NaF 0.22 0.10
SMFP 0.76 0.76 0.76 0.76
ZnS04 0.20 0.20
Neem Extract 0.05
Basil Extract 0.05
Clove Extract 0.05
Ginger Extract 0.05
Amla Extract 0.05
Sodium saccharin 0.30 0.30 0.24 0.24 0.25 0.13
Ti02 0.50 0.50
AOS 2.50 2.50 2.20 2.20 1.50 0.10
Triclosan 0.30 0.30 0.30
Na Benzoate 0.20 0.20 0.20
Bronopol 0.05
Flavor 1.00 1.00 1.00 1.00 1.00 0.35

Table 5 below and Fig. 1 reveals available potassium in aqueous phase of the dentifrice formulation as analyzed by Inductive coupled plasma - optical emission spectrometer (ICP-OES).

Table 5: Available Potassium in presence of AOS &SLS.

Table 6 below and Figure 2 shows drop in potassium activity during over period of time.

Table 6: % loss of Available potassium in 3 months time
It is thus clearly evident form tables 5 & 6 and Figures 1 & 2 that indeed the combination of a soluble potassium salt and AOS surfactant in an oral care composition in one hand favours maximum availability of potassium ions as actives in the oral cavity from its freely soluble form, on the other hand retains the sensorial properties of foaming both in terms of quality and quantity without affecting the after taste of the dentifrice and significantly retaining surfactant activity. It is also found to be stable even after 6 months of accelerated stability testing.

It is thus possible to have a technically advanced oral care stable dentifrice composition like that of the present invention to advantageously have maximum availability of potassium ions as an active in the oral cavity from its freely soluble salt form for effective treatment of dentine hypersensitivity when said soluble form of potassium salt is present in selective combination with an anionic surfactant belonging to the class of long chain olefin sulfonates preferably, (alpha) olefin sulfonates AOS, that in addition retains significant surfactant activity thereby having in the presence of orally acceptable vehicle and other actives in the formulation. The said dentifrice composition is thus therapeutically more beneficial to the users having excellent foam characteristics & good foam stability that also beneficially aids in incorporating higher levels of oral care actives and even in therapeutic amounts and surfactants at orally acceptable levels in an orally acceptable vehicle to be made fully available in said oral cavity without affecting but retaining the sensorial foaming both in terms of quality and quantity and also without affecting the after taste of said composition, all made available in a reduced cost to be thus further attractive to the consumers.

We Claim:

1. A stable dentifrice composition comprising

a. a soluble potassium salt in effective amounts;

b. selective anionic surfactants belonging to the class of long chain olefin sulfonates
in effective amounts;

c. optionally, with or without silica / chalk and other orally useful actives in orally
acceptable vehicle; favouring availability of potassium ions in the oral cavity from its
freely soluble salt form benefitting treatment of dental hypersensitivity with
favourable foam characteristics & stability.

2. A stable dentrifice composition as claimed in claim 1 wherein the preferable long chain olefin sulfonates as the selective anioinic surfactants are (alpha) olefin sulfonates (AOS) and their soluble salts.

3. A stable dentrifice composition as claimed in anyone of claims 1 or 2 wherein said long chain olefin sulfonates are preferably with olefinic group of 8 - 25 carbon atoms more preferably, (alpha) olefin sulfonates (AOS) with olefinic group of 12-21 carbon atoms and their soluble salts like Sodium (alpha) Olefin sulfonates, Potassium (alpha) olefin sulfonates and the like; wherein the concentration of AOS is from about 0.01 % to 20 % by weight, preferably from about 0.1 % to 10 % by weight; more
preferably from 0.5 % to 5 % by weight in said composition.

4. A stable dentrifice composition as claimed in anyone of the preceding claims wherein said effective amount of soluble potassium salt is preferably but not limited to, is selected from potassium nitrate, potassium citrate, potassium chloride, potassium oxalate, potassium bicarbonate, potassium phosphate, dibasic potassium phosphate, tribasic potassium phosphate, and potassium pyrophosphate salts such as dipotassium pyrophosphate, tetrapotassium pyrophosphate, tripotassium pyrophosphate, & monopotassium pyrophosphate or mixures thereof wherein soluble potassium ion in amounts of from about 0.001% to about 2%.

5. A stable dentrifice composition as claimed in anyone of the preceding claims wherein said soluble potassium salt is preferably potassium nitrate in amounts of 0.01% by weight to about 20 % by weight; preferably from about 0.1 % by weight to about 10 % by weight & more preferably from about 0.1 % by weight to about 5% by weight of the composition.

6. A stable dentrifice composition as claimed in anyone of the preceding claims wherein said orally acceptable vehicles includes water, Alcohol, abrasives which may be chalk, silica or mixtures there of and humectants selected from glycerin, sorbitol, xylitol, propylene glycol and / or Polyethylene Glycol, or mixtures thereof in amounts of about 1% to about 99% by weight of the oral composition.

7. A stable dentrifice composition as claimed in anyone of the preceding claims selected from Toothpaste or Dental Cream, Gel, toothpowder, Mouthwash or Mouth rinse, Chewing gum, freshness candy, dental floss adapted for cleaning oral cavity and to maintain oral hygiene.

8. A device for oral care comprising means for containing the stable dentifrice composition as claimed in claims 1-7 and means for selectively dispensing the same for oral care.
Dated this the 4th day of September, 2012