AU597901B2

AU597901B2 - Dental cream

Info

Publication number: AU597901B2
Application number: AU62487/86A
Authority: AU
Inventors: Hermann Gutenberg; Kenneth Harvey; Harry Hayes; Anthony J. Morton
Original assignee: Colgate Palmolive Co
Current assignee: Colgate Palmolive Co
Priority date: 1982-09-14
Filing date: 1986-09-09
Publication date: 1990-06-14
Anticipated expiration: 2003-09-14
Also published as: AU6248686A; AU6248786A; AU577202B2

Description

ai'l iI I COMMONV H OF AUSTRALIA Patent Act 1952 S S P EC I F I CAT ION

(ORIGINAL)

C 0 M P LET Class Int. Class 6 2 7/86 Application Number :6 Lodged Complete Specification Lodged Accepted Published Priority: Related Art Name of Applicant Address of Applicant COLGATE PALMOLIVE COMPANY 300 Park Avenue, New York, New York 1C022, United States of America Actual Inventor Address for Service F.B. RICE CO., Patent Attorneys, 28A Montague Street, SBALMAIN. 2041.

Complete Specification for the invention entitle'2 u. "DENTAL CREAM" The following statement is a full description of this invention including the best method of performing it known to Us:-

II

TO:c>ATT AC.T. SUB-OFFICE COMMONWEALTH OF AUSTRALIA AC.T

-OFF

-0 8 6 0 Collector of Pu~lc Moneys r t 9, -2- DENTAL CREAM Sodium carboxymethyl cellulose has commonly been used as the gelling agent of commercial choice in dental creams in view of its availability and the generally satisfactory theological properties it gives to dental creams, particularly when they are made and used in temperate climates. In tropical climates it can be subject to decomposition by cellalose.

There is an observable tendency of dental creams formulated with many grades of sodium carboxymethyl cellulose to become rolgh (soft lump or chunk formation) in appearance even at room .emperature, particularly when subject to dynaric aging, thiF extrusion of 2cm of dental cream ribbon from a tube twice a day for 2 weeks, a condition which simulates normal use of a dental cream by a single person.

Even grades of sodium carboxymethyl cellulose which do not undergo such roughening upon dynamic aging can reveal other theological problems, for instance poor "stand up" qualities, that is, the rapid settling of the extruded cream into a flat ribbon or thickening with the passage of time.

It is noteworthy that roughening on dynamic aging is particularly observable when the dental cream contains a compound which provides fluoride and a calcium phosphate is present as polishing material. Thus, there is little problem when fluorine is provided from sodium monofluorophosphate or mixture of sodium monofluorophosphate and sodium fluoride and the polishing agent is a siliceous material. However, the problem is readlily observable when fluorine is provided from sodium monofluorophosphate or a mixture of sodium monofluorophospshate and sodium fluoride in a dental cream containing at least about 35% by weight of a calcium phosphate polishing material such as dicalcium phosphate.

1 1 3 Attempts to overcome the roughening problem without having other problems such as poor "stand up" occur by mixing different grades of sodium carboxymethyl cellulose or mixing sodium carboxymethyl cellulose with other gelling agents such as synthetic inorganic sillicated clay (e.g.

materials available under the trademarks "Laponite" and "Veegum"), thickeners such as silica thickeners available from Huber under the trademark "Zeosyl" as Zeosyl 200 and from Rhone Poulenc as Tixosil and as Tixosil 33J or available from Wacker under the identification "HDK and liquid phase material such as polyethylene glycol 600 have not been satisfactory.

Hydroxyethyl cellulose has been suggested as an alternative gelling agent to sodium carboxymethyl cellulose and indeed grades of hydroxyethyl cellulose such as Natrosol M have been used in commercial dental creams and grades have been set forth, for instance in U.S. Patents 3,862,307 (Nat-rosol and 3,070,510 (viscosity of 75-125 cps-Brookfield; 20CC; 2% in water) and 4,022,881 (Natrosol 250 H, a high viscosity material). Such grades of hydroxyethyl cellulose, while generally satisfactory may tend to cause dental creams to undergo extensional rheology by forming a visible "tail" during container filling and upon extrusion onto a toothbrush. For instance, "stringiness" was described in U.S. Patent 4,022,881 in toothpastes containing a thickening agent mixture of hydroxyethyl cellulose and 70% sodium carboxymethyl cellulose. A non-stringy toothpaste containing calcium carbonate abrasive with a thickening agent mixture of hydroxyethyl cellulose and 90% sodium carboxymethyl cellulose was also set forth.

In accordance with the present invention a gelling agent mixture is provided which has little susceptibility to roughness upon aging together with other desirable rheological properties such as good "stand up", absence of

J

i I 4formation of a "tail" on an extruded ribbon of dental cream and good ribbon gloss. Moreover, dental cream can be readily manufactured with this mixture without substantial modification of procedures used when sodium carboxymethyl cellulose is the only gelling agent. The gelling material with which sodium carboxymethyl cellulose is desirably mixed in particular weight ratio is hydroxyethyl cellulose. This material too, although generally good, has not been entirely satisfactory from theological considerations when used alone or in mixture with thickeninq or gelling materials other than sodium carboxymethyl cellulose. Indeed, dental creams containing grades of hydroxyethyl cellulose such as Natrosol 250 M, dicalcium phosphate and a compound which provides fluorine exhibit "tailing" and/or low "stand-up" when grades such as Natrosol 250 M are the sole gelling agent or are present with sodium carboxymethyl cellulose in a weight ratio of sodium carboxymethyl cellulose to hydroxyethyl cellulose (Natrosol 250 M and the like) of below about 2:3, e.g.

about 1:10 and 3:7.

In prior art U.S Patent 4,022,881, mentioned above, a dentifrice was described containing as the thickening agent 5-30% of high viscosity hydroxyethyl cellulose (e.g.

Natrosol 250 H) and 70-95% sodium carboxymethyl cellulose to stabilise the sodium carboxymethyl cellulose against degradation. However, such relative amounts 10:1 and 7:3) are not satisfactory in that they do not avoid the surface roughness which is overcome in the present invention.

S 30 It is an advantage of this invention that a gelling agent system is provided for a dental cream which remains smooth upon dynamic aging and has other generally desirable rheoligical properties.

It is a particular advantage of the invention that dental cream tailing is avoided and stand up is improved I i tjl~ -i ii __1~1 5 even when hydroxyethyl cellulose predominates in the gelling agent system. Such advantage may be particularly evident when dental cream is fill.ed into or extruded from a pressure differential or mechanically operated container or a dental cream tube, particularly with hydrated alumina polishing agent.

The improved advantages may occur with a gelling agent mixture of sodium carboxymethyl cellulose and hydroxyethyl cellulose in particular weight ratio or, when the hydroxyethyl cellulose is of high viscosity, without requiring the presence of sodium carboxymethyl cellulose.

Further advantages of this invention are provided in dental creams containing a source of fluorine, for example a binary source of fluorine from sodium monofluorophosphate and sodium fluoride and a polishing agent including a calcium phosphate.

Other advantages will be apparent from consideration of the following, specification.

There is disclosed in our co-pending application 19102/83 a dental cream comprising a dental vehicle comprising a compound which provides at least about 100 ppm of fluorine selected from the group consisting of sodium monofluorophosphate and a mixture of sodium monofluorophosphate and sodium fluoride in which about 30-40% by weight of said fluorine is provided by said sodium fluoride, about 40-75% by weight polishing agent containing a calcium phosphate in amount of at least about by weight of said dental cream, about 20-80% by weight based on the weight of the dental cream of a liquid phase S 30 containing water, humectant or mixture thereof and about 0.5-5% by weight based on the weight of the dental cream of a gelling agent containing sodium carboxymethyl cellulose and hydroxyethyl cellulose, each being present in a weight ratio of about 3;2 to 2:3 with regard to each other. The foregoing numerical references to viscosities in the -6 present specification refer to viscosities measured in a Brookfield Viscometer in 2% by weight aqueous solution at

C.

The gelling agent is present in the dental cream in amount of about 0.5-5% by weight, preferably about 0.8-2%, and most preferably about the ratio of sodium carboxymethyl cellulose to hydroxyethyl cellulose being about 3:2 to 2:3, typically 1:1 and preferably less than 1:1 to 2:3 (e.g 49:51, 9:11 or 2:3).

Sodium carboxymethyl cellulose is commercially available form Hercules as CMC-,7MXF and 7MFD which are preferred grades in the practice of this invention. Grades may have a degree of polymerization in the neighbourhood of 500, corresponding to a molecular weight in the neighbourhood of 100,000. The viscosity is medium to high, e.g. about 300 to 3000cps or more, typically about 300-1200 cps preferably about 300-500cps (Brookfield, 250C).

CMC-7MXF contains about 0.7 sodium carboxymethyl groups per anhydroglucose unit.

The following table illustrates desirable commercially available grades of sodium carboxymethyl cellulose (CMC) (here the viscosity is measured on other than a Brookfield Viscometer in 2% by weight aqueous solution at 25 0 C, the differences are indicated): TABLE 1 CMC VISCOSITY SUPPLIER GRADE Hercules 7MXF 300-500 7MFD 300-500 9M31F 900-1200 9M31XF 900-1200 12M31XF 900-1200 7MF 300-500 12M31PD 900-1200 7M8SXF 200-800 Wolff Walsrode Walocel CRT 1000 PA 07 700-1200 Nyma Nymcel ZMF.33* 50-90 Enka Akucell AC 1642* 80-120 Akucell AC 1632* 60-120 Cros Cellogen HP-SA 700-900 Uddeholm Cekol MVEP 500-800 Hoechst Tylose CB 200** 120-260 solution (Brookfield; 250C) **Hoeppier Viscometer 20 0

C)

Hydroxyethyl cellulose is commercially available from Hercules as Natrosol 250 M which is a preferred grade in the practice of this invention.

Grades may have a degree of polymerization in the neighbourhood of 750, corresponding to a molecular weight in the neighbourhood of 190,000. The viscosity is medium to high, e.g. about 3000 to 12000 cps or more, typically about 3000-7000 cps and preferably about 4500-6500 cps.

(Brookfield; 25 0 When the viscosity is measured on other than a Brookfield Viscometer in 2% by weight aqueous solution at 25%, the differences are indicated.

The following Table illustrated desirable commercially available gdes of hydroxyethyl cellulose

(HEC):

i 8 TABLE 2

HEC

GRADE

Natrosol 250M and MR

SUPPLIER

Hercules Natrosol 250 HR* and 250H* Natrosol 250 HHR* and 250 HH B.P. Chemicals Cellobond 5000A Cellobond 7000A Hoechst Tylose H 4000P** Tylose H10000P** solution (Brookfield; **Hoeppler Viscometer 200C) The sodium carboxymethyl cellulose

VISCOSITY

4500-6500 1500-2500 3400-5000 4200-5600 6000-7000 3000-5000 7000-12000 and hydroxyethyl cellulose may be mechanically mixed together prior to mixing with the liquid phase of the dental cream vehicle or may be mixed separately with the liquid phase.

Rheological advantages of this dental cream are evident when the dental cream contains a compound which provides at least about 100 ppm, of fluorine, typically about 100-10000 ppm, typically about 750-2000 ppm.

Compounds which provide fluorine include sodium fluoride, stannous fluoride, potassium fluoride, potassium stannous fluoride, sodium hexafluorostannate, stannous chlorofluoride and sodium monofluorophosphate. Most typically in accordance with the present invention sodium monofluorophosphate or a mixture of sodium monofluorophosphate and sodium fluoride is employed. The rheological advantages are also evident when a calcium phosphate polishing agent, particularly dicalcium phosphate is present in amount of at least about 35%, by weight of the dental cream.

Such dental cream typically contains about 35-75% by weight, preferably about 40-55%, of a dentally acceptaole I 12 [i~ 22 1 ii i 9water in-soluble polishing material which consists essentially of a calcium phosphate, such as dical.ium phosphate in its dihydrated or anhydrous forms or as mixtures thereof in any desired ratio, tricalcium phosphate and calcium pyrophosphate. Most typically dicalcium phosphate is employed, generally as the dihydrate. Dicalcium phosphate is typically the sole polishing agent, but if desired minor amounts up to about 5% by weight of the dental cream and up to about 12% by weight of the total polishing material) of other dentally acceptable water-insoluble polishing agents which do not substantially interfere with the ability ofi the composition of the invention to promote oral hygiene may be present. Typical polishing agents are alumina, silica, sodium aluminosilicate etc. A minor amount of hydrated alumina about also inhibits or even eliminates the tendency of some dental creams to separate or "bleed" in their tubes.

This dental cream typically contains sodium monofluorophosphate or a mixture of sodium monofluorophosphate and sodium fluoride in amount to provide about 100-10000 ppm of fluorine, e.g. about 750-2000 ppm, of particularly about 1400-2000 such as about 1400-1670 ppm. A binary fluoride system of sodium monofluorophosphate and sodium fluoride is desirably used in which about 30-40% of the fluorine about 30-35%, that is, about 300-580 ppm) is provided by sodium fluoride.

The gelling agent mixed system is particularly desirable as the galling component of dental creams containing the binary fluorine mixture and dicalcium phosphate polishing agent described in commonly assigned printed British Patent Specification 20 68 727 A (Application 79/43642), the disclosure of which is incorporated herein by reference. Thus, in a typical dental cream, sodium monofluorophosphate is typically used I -m i -ri 10 in the binary system in amount to provide about 700-1090 ppm fluorine to the dental cream in which the total amount of fluorine is about 1000-1670 ppm with about 30-35% weight to the total fluorine being provided by sodium fluoride (about 300-580 ppm). This corresponds to about 0.5-1.2% by weight of sodium monofluorophosphate and about 0.05-0.11% by weight of sodium fluoride. Preferably, the dental cream thereof contains about 1000-1500 ppm, most preferably, about 950-1000 ppm fluorine provided by sodium monofluorophosphate and about 450-500 ppm provided by sodium fluoride.

Sodium monofluorophosphate, Na 2

PO

3 F, as commercially available, may vary considerably in purity.

It may be used in any suitable purity provided that any impurities do not substantially adversely affect the desired properties. In general, the purity is desirably at least 80%. For best results, it should be at least and preferably at least 90% by weight of sodium mornofluorophosphate with the balance being primarily impurities or by-products of manufacture such as sodium fluoride and water-soluble sodium phosphate salt.

Expressed in another way, the sodium monofluorophosphate employed should have a total fluoride content of about 12%, preferably above 12.7%, a content of not more than preferably not more than 1.2% of free sodium fluoride; and a sodium monofluorophosphate content of at least 12%; preferably at least 12.1% all calculated as fluoride.

As indicated above, sodium fluoride in the binary mixture is a separate flourine-containing component from sodium monofluorophosphate. About 300-580 ppm of fluorine is preferably provided to the dental cream by sodium fluoride.

There is also disclosed in our co-pending application 19102/83 a dental cream comprising about 20-75% of a 2 'I 23 -i :i

I'

r 11 polishing material, at least about half of which is hydrated alumina and a dental vehicle comprising about 20-80% by weight based on the weight of the dental cream of a liquid phase containing water, humectant of mixture thereof and about 0.5-5% by weight based on the weight of the dental cream of a gelling agent consisting essentially of hydroxyethyl cellulose having a high viscosity in a range the average of which is at least about 24000 cps, determined on a Brookfield viscometer at 200C, in a water:glycerine (1:1.56) solution with a No. 6 spindle at The gelling agent of this dental cream is present in an amount of about 0.5-5% by weight, preferably about and most preferably about A typical grade of hydroxyethyl cellulose effective in the practise of the present invention is Tylose H10O00P, available from Farbwerke Hoechst of Frankfurt and Main, Germany.

The present invention consists in a dental cream comprising a binary fluorine source of a mixture of sodium monofluorophosphate and sodium fluorine in which about 30-40% by weight of said fluorine is from said sodium fluoride in amount to provide about 750-2000 ppm total of ionic fluorine about 35-75% by weight of a polishing agent consisting essentially of a calcium phosphate and a dental vehicle comprising about 20-80% by weight based on the weight of the dental cream of a liquid phase containing water, humectant or mixture thereof and about 0.5-5% by weight based on the weight of the dental cream of a gelling agent consisting essentially of hydroxyethyl cellulose having a high viscosity of in a range the average of which is at least about 24000 ops, determined on a Brookfield viscQometer in 2% water; glycerine (1:1.56) solution at 20 0 C with a No. 6 spindle at 20 rpm.

Binary fluorine sources are described above. The i u ;i :i 12 gelling agent tihis invention is present in the dental cream in amount of about 0.5-5% by weight, preferably about and most preferably about Tylose H 10000P is a typical grade of hydroxyethyl cellulose effective in the practice of the presenting invention.

Tylose H 10000P and other grades of Hydroxyethyl cellulose in accordance with the present invention have viscosities in a range the average of which is at least about 24000 cps. determined on a Brookfield viscometer at 20°C, in a water: glycerine (1:1.56) solution with a No.

6 spindle at 20 rpm. Values expressed as such differ from differently determined values set forth earlier in the specification. Hydroxyethyl cellulose grades of high viscosity which may be used in the present invention are set forth in the following table:

TABLE

SUPPLIER HEC GRADE VISCOSITY Hercules Natrosol 250 HR and 250 H 17000-31000 Natrosol 250 HHR 37000-41000 and 250 HH SHoechst Tylose H 10000 P 20000-30000 SI, Hydroxyethyl cellulose grades of viscosity not reaching an average of about 24000 cps, such as Hercules 250 M and MR (average viscosity of 15500 cps) and Hoechst 25 Tylose H 4000 P (viscosity of up to 23000 cps), do not provide the desired theology when used as the only gelling agent.

8 In the aspect of the invention in which the dental cream contains about 20-75% by weight of a polishing agent at least about half of which is hydrated alumina, if desired, up to about half of the total polishing agent may be additional dentally acceptable polishing material such as silica, dicalcim phosphate, calcined alumina, zirconium silicate$ insoluble sodium metaphosphate etc.

Preferably about 40-55% of polishing material, typically -13 all hydrated alumina, is present.

The hydrated alumina employed in accordance with the instant invention is preferably small in particle size, i.e. at least about 85% of the particles are smaller than 20 microns, such as that classified as gibbsite (alpha alumina trihydrate) and normally represented chemically as Al1 2 3 .3H 2 0 or Al(OH) 3 The alpha alumina trihydrate may have a size in the range of about 2.6-10 microns. The alpha alumina trihydrate sold by Alcoa as C333 is a fine grade of gibbsite and is particularly highly desirable. The average particle size of C333 alumina is about 7-9 microns (Coulter-Counter). It is obtained by fine grinding of the grade of alumina trihydrate sold by Alcoa as C33. Other grades of hydrated alumina which may be employed include AF 260 and AF 230 sold by British Aluminium Company and SH 4 ,L 100 sold by Rhone-Poulenc.

The hydrated alumina dental cream is typically packaged in a container form from which it can be readily at 20 extruded such as a pressure differential or mechanically 4 operated dental cream dispenser or a lined or unlined aluminium tube or lead tube or laminated tube. The theological properties are particularly desirable when a ,mechanically operated dispensing container of the type 25 described in British Patent Application 2,070,695A, published September 9, 1981, is employed. T'his dispensing container comprises a dispensing mouthpiece, a tension member, a piston and operating hand control. Tha disclosure of this published application is incorporated herein by reference. Pressure differential dispensing container may be of the aerosol or vacuum type.

The hydrated alumina dental cream w contain a compound which provides fluoride or bina, source of fluorine, as described above.

The calcium phosphate dental crear 14 about 35-75% by weight, preferably 40-55% of a dentally acceptable water-insoluble polishing material which consists essentially of a calcium phosphate, such as dicalcium phosphate in its dihydrated oc anhydrous forms or as mixtures thereof in any desired ratio, tricalcium phosphate and calcium pyrophosphate. Most typically dicalcium phosphate is employed, generally as the dihydrate. Dicalcium phosphate is typically the sole polishing agent, but if desired minor amounts up to about 5% by weight of the dental cream and up to about 12% by weight of the total polishing material) of other dentally acceptable water insoluble polishing agents which do not substantially interfere with the ability of the composition of the invention to promote oral hygiene may be present. Typical polishing agents are alumina, Silica, sodium aluminosilicate etc. A minor amount of hydrated alumina about also inhibits or even eliminates the tendency of some dental creams to separate or "bleed" in their tubes.

Tn the dental cream formulations the dental vehicle cowprisss a liquid phass proportioned with the gelling agents to form an extrudIble cteamy mass of desirable consistency. In general, liquids in the dental cream will comprise chiefly water, glycerine, sorbitol, polyethylene glycol 400, propylene glycol, or the like including suitable mixtures thereof. It is advantageous usually to use a mixture of both water and a humectant or binder such as glycerine or sorbitol; typically about 10-30% by weight of water and about 15-50% by weight of humectant. It is preferred to use glycerine or sorbitol. The total liquid content will generally be about 20-80% by weight of the formulation.

Any suitable surface active or detersive material may be included in the the dental cream compositions. Such compatible materials are desirable to provide additional 15 detersive, foaming and cntibacterial properties depending upon the specific type of surface active material and are selected similarly. These detergents are water-soluble compounds usually, and may be anionic, norionic or cationic in structure. It is usually preferred to use the water-soluble non-soap or synthetic organic detergents.

Suitable detersive materials are known and include, for example, the water soluble salts of higher fatty acid monoglyceride monosulphate detergent sodium coconut fatty acid monoglyceride monosulphate), higher alkyl suphate sodium lauryl sulphate), alkyl aryl sulphonate sodium dodecyl benzene sulphonate, higher fatty acid esters of 1,2-dihydroxy propane sulphonate) and the like.

Further surface active agents include the substantially saturated higher aliphatic acyl amides of lower aliphatic amino carboxylic acid compounds, such as those having 12 to 16 carbons in the acyl radical. The amino acid portion is derived generally from the lower aliphatic saturated monoaminocarboxylic acids having about 2 to 6 carbons, usually the monocarboxylic acid compounds. Suitable compounds are the fatty acid amides of glycine, sarcosine, alanine, 3-aminopropanoic acid and valine having about 12 to 16 carbons in the acyl group.

25 It is preferred to use the N-lauroyl, myristoyl and palmitoyl sarcoside compounds, however, for optimum effects.

The amide compound maybe employed in the form of the free acid or preferably as the water-siluble salts 30 thereof, such as the alkali metal, ammonium, amine and alkylolamine salts. Specific examples thereof are the sodium and potassium N-lauroyl, myristoyl and palmitoyl sarcosides, ammonium and ethanolamine N-lauroyl glycide and alanine. For convenience herein, reference to "amino carboxylic acid compound," "sarcoside," and the like _Cw~cF 16 refers to such compounds having a free carboxylic or the water-soluble carboxylate salts.

Such materials are utilized in pure or substantially pure form, They should be as free as practicable from soap or simialr higher fatty acid material which tends to reduce the activity of these compounds. In usual practise, the amount of such higher fatty acid material is less than by weight of the amide and insufficient to substantially adversely affect it, and preferably less than about 10% of said amide material.

Various other materials may be incorporated in the dental creams of this invention. Examples thereof are colouring or whitening agents, preservatives, stabilisers, tetrasodium pyrophosphate, silicones, chlorophyll compounds and ammoniated materials such as urea, diammonium phosphate and mixtures thereof. These adjuvants are incorporated in the instant compositions in amounts which do not substantially adversely affect the desired properties and characteristics and are suitably selected and used in conventional amounts.

For some purposes it may be desirable to include antibacterial agents in the compositions of the present invention. Typical antibacterial agents which may be used in amounts of about 0.01% to about preferably about 0.05%, to about by weight of the dentifrice composition include: N-4(chlerobenzyl) N 5 (2,4-dichlorobenzyl) biguanide; p-chlorophenyl biguanide; 4-chlorobenzyhydryl biguanide; 4-chlorobenzyhydrylguanylurea; N-3-lauroxypropyl-N 5 -p-chlorobenzylbiguanide; 1,6-di-p-chlorophenylbiguanidehexane; 1-(lauryldimetnylammonium)-8-(p-chlorobenzyldimethylammonium octane dichloride; 17 17 5,6-dichloro-2-guanidinobenzimidazole; N -p-chlorophenyl-N -laurylbiguanide; 5-amino-1,3-bis(2-ethylhexyl)-5-methylhexahydropyrimidine; and their non-toxic acid addition salts.

Any suitable flavouring or sweetening materials may be employed in formulating a flavour for the compositions of the present invention. Examples of suitable flavouring constituents include the flavouring oils, oils of spearmint, peppermint, wintergreen, sassafras, clove, sage, eucalyptus, marjoram, cinnamon, lemon and orange, as well as methylsalicylate. Suitable sweetening agents include sucrose, lactose, maltose, sorbitol, sodium cyclamate, sodium saccharine dipeptides of U.S. Patent No.

3,939,261 and oxathiazin salts of U.S. Patent No.

3,932,606. Suitable, flavour and sweetening agent may together comprise from about 0.01 to 5% or more of the composition.

The dental creams should have a pH practicable for use. A pH range of 5 to 9 is particularly desirable.

When the main polishing agent is hydrated alumina, the pH may be 3 to 10.5. The reference to the pH is meant to be the pH determination directly on the toothpastes. If desired, materials such as benzoic acid or citric acid may be added to adjust the pH to, say, 5.5 to 6.5, generally or say 4 to 7.5 for hydrated alumina dental cream.

The dental cream is typically packaged in an e.:trudible tube, such as lined or unlined aluminium or ljad, or laminated tubes generally, and particularly for hydrated alumina dental cream, in mechanical dispensers.

The following examples are further illustrative of the nature of the present invention, but it is to be understood that the invention is not limited thereto. The compositions are prepared in the usual manner and all amounts of the various inqredients are by weight unless otherwise specified.

18 EXAMPLES 1-3-MIXED GELLING AGENT-CALCIUM PHOSPHATE- SINGLE AND BINARY FLUORINE SOURCES EXAMPLE 1 The following dental creams are prepared by conventional dental cream formulation technique with the sodium carboxymethyl cellulose and hydroxyethyl cellulose components being separately added to a pre-mix of glycerine and water. They are placed in aluminium dental cream tubes and dynamically aged by extruding 2 cm. of dental cream ribbon twice a day, five days a week for two weeks.

PARTS

Glycerine Sodium carboxymethyl cellulose (Hercules 7MFD) Hydroxyethyl cellulose (Hercules Natrosol 250 M) Dicalcium phosphate dihydrate Sodium Lauryl sulphate Sodium saccharin Sodium monofluorophosphate Sodium fluoride Flavour Deionized water q.s 22.00 0.44

B

22.00 0.45 0.46 48.00 1.50 0.20 0.76 0.10 0.90 Sto 100 0.50 48.00 1.50 0.20 0.76 0.10 0.90 q.s. to 100 After dynamic aging for two weeks the surfaces of the dental creams are smooth and theologically acceptable. The creams do not tail upon extrusion from the tube and stand-up well on toothbrushes.

Similar theological effects occur at a weight ratio of the sodium carboxymethyl cellulose to the hydroxyethyl cellulose of 3:2.

When the formulas are modified so that the weight 19 ratio of the sodium carboxymethyl cellulose is greater than 3:2 (7:3 and 10:1) surface roughness is observed upon dynamic ageing; when only the sodium carboxymethyl cellulose is present as gelling agent (0.90 parts), the surface can become chunky upon comletion of two weeks of dynamic aging.

When the relative amount of sodium carboxymethyl cellulose to the hydroxyethyl cellulose is below 2:3, the dental creams do not stand up well but capidly settle into flat ribbons. Also as extrusion is completed the ribbons form tails. Tailing is also evident when the hydroxyethyl cellulose is the only gelling agent.

EXAMPLE 2 Dental cream A of example 1 is modified to employ 0.36 parts of sodium carboxymethyl cellulose and 0.54 parts of hydroxyethyl cellulose. The surface is smooth the dental cream does not tail and stands up well.

EXAMPLE 3 Dental cream A of Example 1 is modified to employ 0.45 parts of sodium carboxymethyl cellulose (Hercules 7MFD) and 0.45 parts of hydroxyethyl cellulose (Hercules 250 The surface is smooth, the dental cream does not tail and stands up well.

Similar desirable rheology is observed when dental cream A of Example 1 is modified to employ 0.50 parts of sodium carboxymethyl cellulose (Hercules 7MF) and 0.50 parts of hydroxyethyl cellulose (Hercules 250 MR) with 0.25 parts of tetrasodium pyrophosphate also present.

Similar effects to those described in Examples 1-3 are attained when other grades of sodium carboxymethyl cellulose (e.g Hercules 7MXF, Wolff Walsrode Walocel CRT 1000 PAA 107, Nyma Nymcel XMF.33 and Enka Akucel AC 1632) and hydroxyethyl cellulose Hercules Natrosol 250 HR and Natrosol 250 HHR and Hoechst Tylose H 4000P are used).

Analogous affects to those described in Examples 1-3 p occur when 1.15 parts of sodium monofluorophosphate are present and sodium fluoride is omitted.

EXAMPLE 4-HIGH VISCOSITY HYDROXYETHYL CELLULOSE- HYDRATED ALUMINA-NON-FLUORIDES AND BINARY FLUORINE SOURCES The following dental creams are prepared by conventional dental cream formulation technique. Dental creams A and B are filled into the mechanical dispenser described in published British patent Application 2,070,695A. Dental cream C is filled into an unlined aluminium dental cream tube and dental cream D is filled into a lined aluminium dental cream tube.

p ul~ 21

PARTS

A

23.000

B

23.000 Sorbitol (7Q% solution) Glycerine Hydroxyethyl cellulose (Hercules Natrosol 250M Hydroxyethyl cellulose (Hoechst Ty.,ose H 10000) Alpha alumina trihydrate (alcoa C333) C12-C18 Alcohol Na sulphate (100%AI) Zinc sulphate .7H 2 0 Aluminium sulphate .18H 2 0 Sodium saccharin Methyl p-hydroxybenzoate Sodium monofluorophosphate Sodium fluoride Pyridyl carbinol Allantoin Flavour Phosphoric acid (85%) Deionized water During filling and

C

20.20

D

23.000 1.00 1.00 1.30 1.00 52.000 52.000 52.000 52.000 0.5 0.5 1.5 0.48 0.17 0.17 0.08 0.08 0.76 0.76 0.10 0.10 0.10 0.10 0.15 0.15 1.20 1.20 0.14 0.14 q.s. q.s.

to 100 to 100 upon extrusion the 0.78 0.20 0.17 0.08 0.15 1.00 q.s.

to 100 surfaces 1.20 q.s.

to 100 of the dental creams A, C and D are smooth and rheologically desirable while dental cream B undergoes extensional theology during filling and upon extrusion from its container. Similar rheological effects to those exhibited by dental creams A, C and D occur when Tylose H 10000P of dental creams A, C and D is replaced by Natrosol 250 H and Natrosol 250 HH. Tailing occurs when dental cream B (with p L 22 Natrosol 250 M) is filled into a dental cream tube.

EXAMPLE 5-HIGH VISCOSITY HYDROXYETHYL CELLULOSE CALCIUM PHOSPHATE BINARY FLUORINE SOURCES The following dental cream is prepared by conventional dental cream formulation technique, placed in an aluminium dental cream and extruded by extruding dental cream ribbon twice a day, five days a week for two weeks:

PARTS

Glycerine 22.00 Hydroxyethyl celluloseviscosity 20000-30000 (Hoechst Tylose H10000P) 1.00 Dicalcium phosphate dihydrate 48.00 Sodium lauryl sulphate 1.50 Sodium saccharine 0.20 Sodium monofluorophosphate 0.76 Sodium fluoride 0.10 Flavour 0.90 Deionized water Q.S. to 100 The dental cream does not form a tail upon extrusion and is rheologically desirable.

The rheoloe is also desirable when Tylose H 10000P is replaced by NkAtrosol 250H and by Natrosol 250HH.

When lower viscosity grades of hydroxyethyl cellulose such as Natrosol 250M (Hercules) and Tylose H 4000P replace Tylose H 10000 P, a tail forms upon extrusion of the dental cream.

Although the invention has been illustrated with regard to specific examples and certain variations thereof, it will be apparent to one skilled in the art that various modifications may be made thereto which fall within its scope.

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Claims

1. A dental cream comprising a binary fluorine source of a mixture of sodium monofluorophosphate and sodium fuoride in which 30-40% by weight based on the weight of said dental cream of said fluorine is from said sodium fluoride in amount to provide 750-2000 ppm total of ionic fluorine, 35-75% by weight based on the weight of said dental cream of a polishing agent consisting essentially of calcium phosphate and a dental vehicle comprising 20-80b by weight based on the weight of the dental cream of a liquid phase containing water, humectant or mixture thereof and 0.5-5% by weight based on the weight of the dental cream of a gelling agent consisting essentially of hydroxyethyl cellulose having a viscosity in a range the average of which is at least 24000 cps, determined on a Brookfield viscometer in 2% water:glycerine (1:1.56) aqueous solution at 20°C with a No. 6 spindle at 20 rpm.

2. The dental cream claimed in Claim 1 wherein said binary fluorine source provides 1400-2000 ppm of ionic fluorine.

3. The dental cream claimed in Claims 1 and 2 wherein dicalcium phosphate is present as polishing agent in amount of 40-75% by weight.

4. The dental cream claimed in Claims 1 to 3 wherein said hydroxyethyl cellulose is a grade having a viscosity of 17000-31000; 37000-41000 or 20000-30000. The dental cream claimed in Claim 4 wherein said hydroxyethyl cellulose has a viscosity of 20000-30000.

6. The dental cream as claimed in Claims 1 to 5 wherein said gelling agent is present in amount of 0.8-2% by weight. DATED this 5th day of September 1986 COLGATE PALMOLIVE COMPANY Patent Attorneys for the Applicant: F.B. RICE CO. L. i. .i I .i