CA1261758A - Stable antiplaque dentifrice - Google Patents

Abstract

Abstract of the Disclosure A chemically and physically stable antiplaque dentifrice compris-ing an antiplaque quaternary ammonium compound, a betaine surfactant, a humectant system of glycerin and/or sorbitol and a nonionic gelling agent, prepared by a process which comprises the preparation of two separate gel phases, an oil gel phase and a water gel phase, combining said gel phases into a single gel, and adding a dental abrasive thereto as the final step, or adding said abrasive to the water gel phase prior to the addition of the oil gel phase.

Description

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The present invention relates to the formulation of an anti-plaque dentifrice with improved foaming, improved taste, solubilized active ~ ingredient, improved fluoride stability, improved compatibility of all : components, improved extrusion characteristics from various containers and increased cost effectiveness.

I ~2~1758 ! Until now i~ had been diff~cult ~o ~ormula~ a cosmetically acceptable antiplaque dentifrice consisting Or a il quater~ary ammonium compound and a betaine surfacta~t with a humectant system of all glycerin or all sorbitol. In addition~
ths use of mixtures of glycerin~polyethylene glycol or sorbitolJ
polyethylene glycol, where glycerin or sorbitol ~ere pre~ent ~n excess of 10~ by weight of the formul~tion9 dl~plar~d marg~nal : cosmetic s~ab~lity 3 However, after axtensive ~olubilit~ tests on various mixtures of the components in the benze~honi~m chloride (BTC) dentirrice, a compatibl0 system of water, 9TC, betaine, salts and glycerin was found wh~ch was dspendent upon the order of addi~ion o~ these co~ponentsO
:~ Accord$ngly7 i~ has been ~ound that by using a specific ~ process, stabla rormulations o~ an antiplaque den~l~rice con-:: taining a quaternary ammonium compound and a betalne surfac~an~
can be made with glycerin or sorbitol as the hwmectant~ The essential features in t~s process is the forma~ion o~ ~wo separate phases with ~he su~sequent combination of these two . phases ~o form the s~able sys~em. One o~ the~e phases contalns the active quatarnary ingredient ~benzethonium chloride or ce~yl pyr~dinium ohloride3 sslub~lized ~ the be~alne &urractant ~2~1~58 ~cocamidopropyl betaine) and a fla~or~ which is designated the oil gel phase. The second phase contains water9 h~mectant~ and nonionic gelling agent e.g. hydroxyethy~cellulose, and optionally sodium saccharin and fluorine-Gontaining compound i.e. sodium monofluo~ophospha~e, and is designated the wa~er gel phase. The dental polishing agent may be added to the combined phases a~
a final st~p, or be added to ~he watcr g~l pha8e prior to com-bi~ing with the 9il gel phase. The finished product has impro~ed chemdcal and cosmetic stability and improved taste~
A conven~ional method 'of preparing an~ibacterial dentifrices con~aining a quaternary ammonium compound a5 ~he ackive ma~erial is disclosed in U. S. Patent No. 4~ 76 and U~ S~ Patent No. 4~1~B,372, and comprises the formation of a gel w~kh humectant (~lycerin, sorbitol~ polyethylene glycol), thickener (hydroxyethylcellulose), and sweetener~ and adding ther0to polishing agent, flavor, antibacterial agent, ~dditional water9 and lastly an antista$n agent (a phosphono~con~ainlng compound or a melli~ic acid-contain~ng compound).
The prior art also discloses processes ror stabilizing "
a den~ifrice aga~nst precipitation and ~lo~ulat~on due to the incompatibility of an antibacterial agent and an al~ali metal carboxyal~y cellulose, as shown in U. 5. Patent No. 3,~42~165 ~ ~ ' ' .
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lZ~j1758 and No. 3~B~3,779. The former pa~ent u~ilizes ~he steps of adding the an~ibacterial agent dissolved in water to a ~on-aqueous blend of the carboxymethylcellulose~ sodium saccharin and humectant and ~hen adding ~he surfactan~ ~o ~orm a gel, to which is added the polishing material and flavor as a ~inal step~ The latter pa~ent adds the antibac~erial agent separately or cojointly with the surPactant ~o a mixture of glycerin, water~ sodium saccharin, carboxymethylcellulose and surfaGtant, followed by the addition of a polishing ma~erial and flavor~
The addition of the surfac~an~ must precede or be si~ultaneuus with the antibacterial add~tion $n order to avoid precipitatlon in the dentifrice.
H~we~er~ the prior art does no~ disclose a cosmetic, and chemically stable antiplaque dent~frice conta~n~ng as the .
essential ingredients, a quaternary ammonium antiplaque com- .
pound, a zwit~erionic be~aine surfactant, a glycerin ~nd/or sorbitol humec~antg and a non~onic gelling agent prepared by a novel process ut~lizing a speci~ic sequence o~ st~ps, which comprises the formation.o~ two separat~ gel phases~ an oil gel , phase consisting of the qua~ernary ammon~um compoundg betaine surfactant and fla~or; and a water gel phase consisting o~

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lZ6~75~3 1 ' water, humectant and gelling agent; combining ~he ~wo gel phases : into a single parent gel, and adding a dental abrasive to the ,I combined gel phase as a ~inal step or to the water gel phase , prior to the addition of the oil gel phaseO

I It has now been found that stable ~ormulations of an ,1 anti-plaque den~ifrice containing a quaternary ammonium compound, ~" and a betaine surfactant, can be made with glycerin or sorbitol `! as the humectant ~y utilizing a specific sequence of steps which ¦ comprises the formation of a separate oil gel phase of the quaternary ammonium compound~ betaine and fla~or, a separate il water gel phase of humectantj nonionic gelling agent and water j (which may preferably contain the salts~ i.e. sodium saccharin ¦l and sodium monoflurophosphate or other fluoride salt), com-'~ bining the oil and water gel phases to form a stable parent gel ! phase, and adding a dental abrasive as the final stepa This i process may be varied by adding the polishing agen~ to ~he water l gel and then adding the oil gel to the water gel-abrasive mixture~
: I This dentifrice is prepared at ambient temperature3 i~e. each ¦ step in ~he total sequence of steps is performed at ambient 1~ (room) empera~ure.

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~6~7S~3 In the present invention there is formulated a stable antiplaque dentifrice based on quaternary active ingredients, and a betaine surfactant, with improved compatibility of all components, by the formation of two separate gel phases, which are combined to form a stabletotal gel system.
The present invention attempts to provide a cosmetically and chemically stable antiplaque dentifrice containing glycerin and/or sorbitol as humectant which is compatible with the betaine and the quaternary active ingredients.
In this invention there is provided a stable antiplaque dentifrice containing a nonionic gum, such as hydroxyethylcellulose, as gelling agent to attempt to stabilize the betaine-quat. system and to prevent deactivation of the quaternary active ingredient.
This invention also attempts to provide a cosmetic (physical) and chemically stable antiplaque dentifrice also con-taining a fluoride-providing compound, without adversely affecting cosmetic stability of the dentifrice.

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~17S8 62301~1330 In accordance with the present invention, there is provided a chemically and physically stable antiplaque denti-frice comprising an antiplaque-effective amount of an antiplaque quaternary ammonium compound, about 3 to 5% by weight of a betaine surfactant, about 0.5 to 2~ by weight of a flavor, about 18 to 23% by weight of a humectant system of glycerin or sorbitol and about 0.8 to 1.5% by weight of a nonionic gelling agent, prepared by a process which comprises the preparation of two separate gel phases, an oil gel phase and a water gel phase, combining said gel phases into a single gel, and adding a dental abrasive thereto as the final step, or adding said abrasive to the water gel phase prior to the addition of the oil gel phasel wherein the oil gel phase consists of the quaternary ammonium antiplaque compound, a betaine surfactant and a fla~or;
the water gel phase consists of water, humectant and nonionic gelling agent; and the dental abrasive comprises 35-65% by weight of the dentifrice.
The dentifrice is prepared at ambient temperature by the process which comprises the formation of two separate gel phases, an oil gel phase consisting of the quaternary ammonium antiplaque compound, the betaine and a flavor; and a water gel phase consisting of water, humectant and nonionic gelling agent;
combining the two gel phases to form a single gel phase: adding a dental abrasive to said combined gel phase. The sequence of addition may be varied by adding the dental abrasive to the water gel phase prior to combining with the oil gel phase.
~i However, it is essential that two separate gel phases be pre-pared prior to the addltion steps. The addition of salts such as a fluorine-containing compound and/or sodium saccharin, ? i~ ~ ~
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', ~26~5~ 62301-1330 which are preferred components, is made by disso~ving in the formula amount of water prior to mixing the water with the humectant and gelling agent in the formation of the water gel phase.
The present invention also relates to a novel process of preparing the cosmetic and chemically stable antiplaque dentifrice defined above and consisting essential-ly of the formation of two phases, an oil gel phase and a water gel phase comprising the following sequence of steps:
a. dispersing the formula amount of a quaternary ammonium antiplaque agent in the formula amount of flavor, b. mixing said quaternary ammonium-flavor dispersion into the formula amount of betaine surfactant to form the oil gel phase, c. dispersing the formula amount of nonionic gelling agent in the formula amount of glycerin or sorbitol humectant, d. mixing said gelling agent-humectant dispersion with the formula amount of water to form the water gel phase~
e. combining the two gel phases to form a stable - parent gel phase, i, ~' ~t ~ i261'758 '~

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f. adding the dental abrasive t~ the water gel phase or to the parent gel phase with mixing, and g. recovering a stable antiplaque dentifrice.

The oil gel phase i5 in ~h~ form of a riscous, trans-lucent gel7 The wa~er gel phase is transparent. The stable parent gel phase resembles an emulsified system.

This process may be modified by adding a~d mixing thedental abrasive with ~he water gel phase, and ~hen add~ng the oil gel phase to the mix~ure of den~al abrasi~e and water g~l phase.
~ odium saccharin and/or a fluorine-containing compound, which are optionally pref0rred additives, are dissolved ln the formula amount of water prior to lts addition to the humectant-gelling agent dlspersion and the ~ormation o~ ~he water gel phas~O
The new formulation method of in~tant invention using only glycerin andJor sorbitol humec~ant in a quaternary-be~aine system provides chemical and cosmet~c stability ~o the denti-frice as well as impro~ed tas~ec The tas~e characteristics of a ~0% containing glycerin or sorbitol humectant, benzethonium chloride (BTC), betaine denti~rlce are grea~ly improved when _9_ ~2~17~
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compared ~o a 20~ polyethylene glycol (P~G 600) BTC dentifrice. I
The stability afforded by the glycerin and/or sorbitol numectant I
does not extend to o~her humectants such as polyethylene glycolO
A precipitate has been observed in ~he 20~ PEG 600 humectant gel phase o~ the BTC den~ifrice. The precipi~ate was analyæed using an IoR~ spectrophotometric method and was found to be co~pris~d of ~TC9 sacch~r~n and bataine~
Fluoride stability studies on the BTC dentifrice ha~e confirmed that a large part of MFP loss is due ~o hydrolysis in an all PEG 600 humectant system. Other phenomena (i.eO adsor-pt~on or insolubilization) may be responsible as well. A
solubility problem with PEG 600 and monofluor~phosphate (MFP) has been found. Stability studies of MFP in the BTC dentirrice indicate ~hat hydrolysis of MFP occurs to a large extent in an all PEG 600 humectan~ systemO However~ an all glyceri~
humectant system in ~he BTC denti~rice displays much les~ loss of MFP. In fact an all glycerin humectant system meets the pr~sent re~iremene ~or MFP shelf life ~more than 600 ppm total oluble ~luoride9 hal~ of which i.s MFP) while an all PEG 600 .
humectdnt c tem does no~ (889 ~able I below~. l '~. .
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i TABLE

MFP Stabilit,y in BTC Dentifrice With ! :~ I
Glycerin ~umectant_System pH Soluble F * Ionic F * MFP as F
;~* L_~ I 3w 6w ~w I 3w 6w 9w PEG ~2 10.1 9gO 660 ~70 520 57 2~9 439 431 ~20 370 130~100 GlycO 70~ ~3 9~0 B70 790 790 2655 g5 106 950 ~10 70û 6~0 *
w _ weeks This table clearly shows the poor ~tabllity Or MFP in an all PEG 600 humectant and the ~rery good stabili'cy o~ MF~ in an all glycerin formulation.
HPLC (High Pressure Liquid Chromatography) anabsis bo~h a gl.ycer~n and a sorbitol ~rC dent~r~ce ~ormulat~ was performed initiall~ and after nlne weeks accelerated aging at 49 C . Two extraction methods for BTC (water and ace~one) indi-cate no decrease in BTC reco~ery after aceelerated aging (see Ta~le II).

i~61758 Initial AnalYsis Analysis After A~inF
~ater Acetone Water Acetone HumectantExtraction Extraction Extraction Extraction .
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20~ Glycerin0~42 ~.54 0.~7 0~52 20~ Sorbitol0,36 00~ 0~45 0.46 The glycerin and~or sorbitol humec~ant system constitutes about 1~-23~ by weight of the dentifrice composition.
., Cationic antibacterial materials are well known in ths ar~. See, for instance the sec~ion on "Quaternary Ammonium and Related Compounds9~ in the article on "Antiseptics and Disinfect-ants" in Kirk-Othmer Encyclopedia of Chemical Technology, 2nd edition (Vol. 2, pp. 632-63~)~
Cationic materials which possess antibacterial activity (i.e.
are germicides) are used against bacteria and ha~e been used in oral compositions to counter plaque formation caused by bacteria in the oral cavity~
:~ Among the most common of these antibac~erial antiplaque ;` quaternary ammonium compounds is benzethonlum chloride, also known as Hyamine*1622 or diisobutylphenoxye~hoxyethyl dimethyl benzyl ammonium chloride~ and cetyl pyridinium chloride. In an ~: oral preparation this material is hignly effecti~e in promoting :~
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oral hygi~ne by re~ucing formation of denkal plaqu~ ~nd ~alculus, which is generally accompanied by a reduction in periodon~al diseases. Other ca~ionic ant~bacterial agent~ o~ tb~s type are those ~ent~oned9 ~or instance, in U~ S. Paten~ Nos. 2,9~4,639, 3,325~40X, 3,431,20~ and 3,703,5g3, and Bri~ish Patent No. 1, 319~3960 Other antibacterial antiplaque ~ua~ernary a~mon~um compounds include those in which one or two o~ ~he subst~tuents on the quaternary nitrogen has a carbon chain length (typically alkyl group) of some ~ to 20, ~ypicallg 10 to 1~, carbon atoms while ~he remaining subst~tuents haYe a lower number of carbon atoms (typically alkyl or benzyl group~J such as 1 to 7 carbon atomsp t~pically methyl or ethyl groups. Dodecyl trimethyl ammon~um brom$de9 benzyl dimethyl ~tearyl ammonium chloride9 cetyl pyridinium chloride and quaternizsd 5-amino-1,3-bis (2 ethylhexyl) 5-methyl hexa hydro~pyrimidine are typical qua~er nary ~ onium antibac~srial agen~s.
The dentifrice ~ormulation of present invent~on co~tains an ef~ect~ amoun~ Or the ankiplao,ue qua~erna~y a~monium co~, pound, pr~fsrably abou~ 0~1-1% by weigh~ o~ the co~posi~onQ
The ability of quaternary ammonium compounds to inhi~t ~13-the ~ormation of dental plaque is well k~own~ NoweYsr, ~hey are deacti~ated by ~he anionic sur~actan~s such as sodium lauryl sulfa~e conventionally used in den~ifrice formulations~ The substitution of nonionic surfactan~s for the anionic sur~actants eliminates the deactivation problem but results in products w$th poor foaming. However, ~he incorporation of betaine surfactants into antiplaque dental ~ormulation~ based on quater-nary active ingredien~s unexpec~edly ~proves the roaming o these formulations wi~hout deacti~ating th~ quaternary anti-bacterial agents~
Tho betaine com~onent of present dent$frice composltion has ths general formula:

R -N~ ~ -C00~~

wherein Rl is an alkyl group ha~ing 10 to about 20 carbon atoms, s preferably 12 to 16 carbon atoms or ~he amido radical:

R-C-N-(CH2) .

_~_ !, - i 1261'758 lll wherein R is an alkyl group having a~out lO to 20 carbon atoms and a i5 ~he integer 1 to 3; R2 and R3 are each alkyl groups having 1 to 3 carbons and preferably 1 carbon; Rl is an alkylene or hydroxyalkylene group having from 1 to 4 carbon atoms and, optlonally, one hydroxyl group. Typical alkyldimethyl betaines include decyl betaine or 2-(N-decyl-~,N~dimethylammonio~ acetate, coco betaine or 2-(N~coco-N,N-dimethylam~on~o~ acetate~ ~yristyl betaine, palmi~yl betaine, lauryl betaine, cetyl betaine, stearyl betaine, etc. The amidobetain~s similarly include cocoamido-e~hyl betaine~ cocoamidopropyl botaine, lauramidopropyl betaine and the liksO
The betaines~ which are 3witterionic materialsg function as a foaming agent in the quaternary-containing denti-frice compositions. They act cationically over a wide pH range, but do not deacti~ate the quaternary an~imlcrobial acti~ity.
In addition ~o the non~in~erference exhlbi~ed by the betaines with the quaternary activity~ la~orakory foam ~ests ha~e shown that ~ormulations co~taining bokh the quaternar~
ammonium compound (qu~t~ and the betaine, rOam 2-3 time~ be~ter than the nonionicjquat ~ormulation~.
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1l i The zwitterionic betaines are completely compatible i with the qu~ernary antimicrobial antiplaque agents, and impart , detersive and improved ~oaming prop~rties to the quater~ary-containing denti~rice composition without deactiYating the antimicrobial properties thereo~O The a~ount o~ betaine effect-i~e in ~he production o~ improYed foaming ~ay be ~aried from ~ about 3-50~ by we~ght of the total for~ula~$on.
: Cosmet~c pro~l~ms of stability` i8 ~ncurred with all zwikterionic containin~ den~ifrices, such as crimp leakage o~ rlavorO Ths flavor oozes and is not solubilized ~n the zwitterionic sur~ac~ant~ However, stability evaluativ~s o~
present no~el antiplaque dentifrices conta~ning glycerln a~d/or sorbitol humectant indicate satis~actory M avor s~a~ility : for nine weeks ag~ng a~ 49 & . The flavor ~ngredien~ whi~h is : an ess~ntial ingredient ln a dentiriGe cons~itutes about 0.~-2%
by weight~ ~ny sui~able flavor may be ~mployed. Ex ~pIes o~
: suitable flavoring constituents are flavoring oils9 e-gO~ oils of spearmint, peppermlnt~ w~ntergree~ sassafras, clo~e, sage, eucalyptus~ mar~oramy cinnamon~ lemon9 and orange9 and methyl ., ~ sal~cylateO
: A sw~etening mate~ial may also be employed ag a ~ complemen~ to the M aYorlng materialO Su~table ~weetan~ng '~: :

agents are water soluble and include sucrose~ lactose, maltose, sorbitol~ sodium cyclamate, and saccharin~ in an ~mount of 0~01-0~5~o by weight.
Another essential ingredient in presen~ den~ifrice is a gelling agent which is a nonionic gum, ~n an am~unt o~
about 0,~-1.5% by weightc It has been found that large organic anionlc molecules such as carboxymethylcellulose haYe tha potential to deactivate the quaternary antibacterial acti~ity.
Accordinglyp hydroxyethylcellul3se, which ~s a nonionic small organic molecule, effects a stable pituitous gel in the betaine-quat system of present invention, and is the pre~erred gelling agent. Other nonionic gelling agents may be used such as hydroxymethylcellulose, and the like.
The fluoride-providing compounds, which are pre~erably addi~ional ingredients in present d0nti~rice, are charac~erized by their ability to release fluoride ions in wa~er and by sub-stantial freedom from reac~ion wi~h other comp~unds of th~
dentifrice. :Among these materials are inorgani c fluoride sal~s, such as soluble alkali ~etal, alkaline earth metal and heaYy metal saltsg for ex~4ple, sodium fluorid~, po~a9sium :~
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lZ617513 i ~luoride, ammonium fluor~de, lead fluorid~ a copp~r fluoride such as cuprous fluoride~ zinc fluorid~9 a tin fluoride such as stannic fluoride or stannous chlorofluoride, barium fluoride, sodium fluorosilicate, ammonium fluorosilicate7 sodium f}uoro ~irconate, sodium monofluorophosphate, aluminum mo~o- and di-~luorophosphate9 and fluorinated sodium calciu~ pyrophosphate.
Alkali metal and tin fluorides, such as sodiu~ and stannous fluorides, sodium monofluorophosphate and mixtures thereof, are preferred.
The amoun~ of the ~luoride-pro~idi~g compound is dependent to some extent, upon the type of compound, iks solubility, and the den~i~rice, bu~ it must be a nontoxic amount. In a solid oral preparation, ~uch as a toothpaste or dental cream, an amount of such compound whlch raleases a maximum of 1% by welght o~ the prepara~ion is considered satis-factory. Any suitable minimum ~mount of such co~pound may be used, but lt is prererable to employ su~icie~t compound ~o release rrom 0.005% to 1%~ and preferably abou~ 091% O~ fluoride ion. Typically, in the cases o~ alkali me~al ~luorides and stannous ~luoride~ this componen~ is present ln an amount up to 2~ by w gh~, baeed o~ the welght of the preparatio~. Ir ;~
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126175~ 1 1l the case ~f sodium monofluorophospha~e, ~he compound may be presen~ in an amount up to 7~6% by weight9 re kyplcally 0076%.
The den~ifrice prepared in accordance wi h this inYen-tion, contain~ conYentional waterinsoluble polishing materials or dental abrasi~es~ in amounts ~rom about 35-65~ by weight of the total formulationO Suitable examples of dental abrasives or polishing materials include sodium me~aphos~hate, potassium metaphosphate, tricalcium phosphate, dihydrated ~alcium phosphate, anhydrous dicalcium phosphate, calcium pyrophosphate, magnesium orthophosphate, ~rimagnesium phosphate, calcium carbonate, zir-conium silica~es~ silica9 bentonite~ and mixture~ ~hereo~O The preferred abrasiYes are alumina-contai~ing abrasi~e~ such as calcined alumina and hydra~ed alumina and mixtur~ ~hereo~. The abrasive is added to the water gel phase or ~o the single gel after combining ~he oll gel and water ~el phases~
The dentifrice of ~his invent~on may al80 contain con-ventional additional ingredients .uch as coloring or whitening agent~, preservati~es and ammonia~ed material~ such as mono- ¦
ammonium glycyrrhi3inate~ These addi~ional i ~redients may each ;
be added ~o ~he dentifrice in minimal amoun~s o~ up to 5~ by .
weight, and preferably up to 1~, provided they do not in~er~ere w~th the ~o~ming, antiplaque and s~ability propertie~ o~ ~he finished product. The oil phase typically cons~itutss ab~ut 3.6-~ by we~ght of the dentirrice.

~2~175~ 62301-1330 In the practice of this invention to promote oral hygiene, the dentifrice according to this invention is applied regularly to dental enamel by brushing the teeth for 30-90 seconds at least once daily.

The following examples are further illustrative of the nature of the present invention, but it is understood that the invention is not limited thereto. The compositions are prepared in the usual manner and all amounts and proportions referred to herein and in the appended claims are by weight unless otherwise indicated.
Example 1 Glycerin Humectant Anti-Plaque Dentifrlce Ingredients Water (Deionized) 19.34 Sodium Saccharin 0.30 Sodium Monofluorophosphate0.76 Hydroxyethylcellulose 1.10 , ! 12617S8 !
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Ine,redients Glycerin 20.00 ~enzethoniu~ Chloride 0~50 Flavor loO0 Cocamidopropyl Betaine 5000 Calcined Alumina 10~00 H~drated Alumina 42000 The ben ethonium chloride is dispersed ln ~he flavor and this dispersion is mixed into ~he betaine to form an oil g~l.
The sodium sacchar~n and sodium monofluorophosphate (~FP) are dissolved in the water. ~ydroxyethylcellul~se i8 disper~ed in the glycerin~ and this mixture is added to the water-saccharin-MFP solution with ~tirring ~o form ~ w~ter gel~ The oil and water gels are mixed to form a s~able parenk gel. The calcined alumina and hydrated alumina ar@ admixed with the parent gel to produce ~he ~inished dentifrice which is e~fective against plaque related bacteria while possessing excellen~ chem~cal 7 and cosme~ic stabil~y as well as hav~ng suf~icier~ ~oaming characteristicsO This den~ifrice is prepared a~ room temper-stllreO
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,I EXAMPL~ 2 ! .
¦j Example 1 is repeated except tha~ 20~ ~orbitol is Il subs~ituked for the 20~ glycerin~ The resultan~ product is equally effec~ive against plaque related bacteria and also possess exc~llent chemical and cosmetic stability and su~ficient foaming properties.

: MFP stability studies indicate that both the new :~ glycerin and sorbitol dentifrices have an excellent M~P stability ; profile. ~xample 1 ~20~ glycerin) had an initi~l to~al soluble M uoride value of 990 ppm a~d an M~P as F ~alue of 950 ppm.
Example 2 (20~ sorbi~ol) had an ini~ial total soluble fluoride value and an MFP as F value of 19020 ppm and 9~0 ppm respecti~ely ~See Table III~.

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Hu=ectant ~

1 All Glycerin 7.~ ~OC 990 ~20 ~3 94 950 730

2 All 3Orbitol 7.6 7.7 1020960 43 45 9~0 910 Th~ pH profiles of bo~h formN~ations showed only a sl~ght increase after nlne weeks aging at 49C. Af~er accelerated aging, values for total ooluble fluoride and ~PP as F were ~20 ppm and 730 ppm respecti~ely for Example 1 and 960 ppm and 910 ppm respectiYely for ~xample 2.

Variations in the above ~ormulations may be made. For example, other betaines such as lauramldopropyI be~aine, coco-betaine and the like may be substi~uted for th~ cocoamidopropyl betaine in the examplesO Similarly, other abrasi~es may be substitu~ed for tha specific abrasives in the examples~ ~ike-wiset other fluoride-con~ai~ing compound~ such a~ æodium fluoride, potassium ~luoride, etc~ may be substi~uted ~or the sodium mono~luorophosphate in ~he spe~iri~ examples. Li~sw~se, cetyl pyridiniu~ chlor~de or othsr quaternary amnonium a~iplaque agents may be substituted Por the bensethonium oride. A1809 :~ sodium cyclama~e may replace sodium sac~harin.
: It ~s under~tood that ~he roregoing de~a~led d~scrip-;~
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1~61758 1 i ¦¦tion is given merely by way of illustration and that variations I may be made therein without departing from the sp~rit of the inYention. The "Abstract'~ gi~en aboYe ~s merely for ~he con- ¦
l ~enience of technical searchers and is no~ to be given any ; weight with respect ~o the scope of the invention.

Claims (17)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A chemically and physically stable antiplaque dentifrice comprising an antiplaque-effective amount of an anti-plaque quaternary ammonium compound, about 3 to 5% by weight of a betaine surfactant, about 0.5 to 2% by weight of a flavor, about 18 to 23% by weight of a humectant system of glycerin or sorbitol and about 0.8 to 1.5% by weight of a nonionic gelling agent, prepared by a process which comprises the preparation of two separate gel phases, an oil gel phase and a water gel phase, combining said gel phases into a single gel, and adding a dental abrasive thereto as the final step, or adding said abrasive to the water gel phase prior to the addition of the oil gel phase, wherein the oil gel phase consists of the quaternary ammonium antiplaque compound, a betaine surfactant and a flavor; the water gel phase consists of water, humectant and nonionic gelling agent; and the dental abrasive comprises 35 - 65% by weight of the dentifrice.

2. The dentifrice in accordance with Claim l, wherein a fluorine-containing compound is dissolved in the formula amount of water prior to the addition of the water to the humectant and gelling agent in the formation of the water gel phase.

3. The dentifrice in accordance with Claim 2, wherein a water-soluble sweetening material is dissolved in the formula amount of water prior to the addition of the water to the humectant and gelling agent in the formation of the water gel phase.

4. The dentifrice in accordance with Claim l or Claim 2, wherein sodium saccharin sweetening material is dissolved in a formula amount of water prior to the addition of the water to the humectant and gelling agent in the formation of the water gel phase.

5. A process of preparing a cosmetic and chemically stable antiplaque dentifrice comprising an antiplaque-effective amount of a quaternary ammonium compound; about 3 to 5% by weight of betaine surfactant; about 0.5 to 2% by weight flavor;
about 18 to 23% by weight of at least one of glycerin and sorbitol humectants and about 0.8 to 1.5% by weight of a non-ionic gelling agent, consisting essentially of the formation of two phases, an oil gel phase and a water gel phase comprising the following sequence of steps:
a. dispersing a quaternary ammonium antiplaque agent in flavor, b. mixing said quaternary ammonium-flavor disper-sion into betaine surfactant to form the oil gel phase, c. dispersing a nonionic gelling agent in glycerin or sorbitol humectant, d. mixing said gelling agent-humectant dispersion with sufficient amount of water to form the water gel phase, e. combining the two gel phases to form a stable parent gel phase, f. adding the dental abrasive to the water gel phase or to the parent gel phase with mixing, and g. recovering a stable antiplaque dentifrice.

6. The process according to Claim 5 wherein a water-soluble sweetening material, a fluorine-containing compound or both are dissolved in the formula amount of water prior to its addition to the humectant-gelling agent dispersion in the formation of the water gel phase.

7. The process according to Claim 6 wherein said sweeten-ing material is sodium saccharin and said fluorine-containing compound is sodium monofluorophosphate.

8. The process according to Claim 5, wherein said nonionic gelling agent is hydroxyethylcellulose.

9. The dentifrice of Claim 1, wherein the nonionic gelling agent is hydroxyethylcellulose in amounts of about 0.8 - 1.5% by weight.

10. The dentifrice according to Claim 1, wherein the dental abrasive is an alumina-containing abrasive.

11. The dentifrice according to Claim 10, wherein the antiplaque agent is benzethonium chloride in an amount of about 0.1 - 1% by weight.

12. The dentifrice according to Claim 2, wherein the fluoride-providing compound is present in an amount suficient to release about 0.005 - 1% by weight of fluoride ion to the dentifrice.

13. The dentifrice according to Claim 12, wherein the fluoride-providing compound is sodium monofluorophosphate.

14. The dentifrice according to Claim 1, wherein the betaine is cocoamidopropyl betaine.

15. The dentifrice according to Claim 10, wherein the abrasive is a mixture of hydrated alumina and calcined alumina.

16. The dentifrice according to Claim 1, wherein the flavor constitutes about 0.5 - 2% by weight.

17. The dentifrice according to Claim 1 wherein sodium saccharin constitutes about 0.01 - 0.5% by weight.