GB2152371A - Dentifrice composition containing carrageenan - Google Patents

Abstract

A dentifrice composition of desirable rheological properties comprises an alpha-alumina trihydrate polishing agent, sodium fluoride, sodium monofluorophosphate, allantoin and pyridyl carbinol in an aqueous gelled humectant base, the gelling agent being a mixture of a cellulosic gelling agent such as sodium carboxymethylcellulose, or xanthan, with iota-carrageenan.

Description

SPECIFICATION Dentifrice Composition The present invention relates to a dentifrice composition. In particular, it relates to a dentifrice composition having desirable rheological properties suitable for efficient filling into a mechanically operated or pressure differential dentifrice dispenser and extrusion therefrom.

A dentifrice is generally recognisable by its creamy or gel consistency and may commonly be called a dental cream, a toothpaste or, in some cases, a clear gel or opacified gel toothpaste. Indeed, it can be characterised as semi-solid, for instance, being essentially solid when standing on the bristles of a toothbrush and essentially liquid such as during manufacture with agitation and filling into a container or when subject to pressure to extrude the dentifrice from its container.

The creamy consistency of dentifrices is typically imparted by a gelling or binding agent. In the past, gelling agents have been selected primarily to provide ease of dispersion of the dentifrice in the oral cavity.

Many gelling agents such as cellulosic materials, seaweed derivatives, gums and clays meet this criteria.

However, some gelling agents while generally desirable for dentifrices packaged in flexible tubes, do cause disadvantages when the dentifrices are packaged in mechanically operated or pressure differential dispensers.

Dentifrices containing conventional polishing agents such as alpha-alumina trihydrate and conventional gelling agents such as sodium carboxymethyl cellulose or hydroxyethyl cellulose or mixtures thereof can be desirably filled into flexible tubes or mechanically operated or pressure differential dispensers and extruded therefrom. However, with many of the active ingredients often used in dentifrices difficulties occur when attempting to fill a dentifrice into a mechanically operated or pressure differential dispenser and/or when attempting to extrude it therefrom. In particular, leakage from orifices in the dispensers may occur during filling or shipping and the product can be difficult to extrude in rheologically desirable ribbon form.

Dentifrices which are thick or tend to thicken may become increasingly difficult for a consumer to extrude from a dentifrice tube over a period of time. In other words, the consumer may have to increase pressure on a dentifrice tube containing such a dentifrice during the period of use in order to soften or liquifythe semi-solid dentifrice mass to extrude it. This has not been a major problem in the past since formulations can be adjusted to use less gelling agent to strike a balance of not being too soft at the start of use and not too thick at the end and in any event consumers have readily adjusted to applying the amount of pressure necessary to extrude the desired amount of dentifrice on to bristles of a toothbrush.

Dentifrices which are thin upon extrusion from a tube have also been tolerated during use if they set to more solid form on toothbrush bristles within a few seconds. Thus, the type of gelling agent could be widely varied for dentifrices packaged in tubes. Indeed, the Copenhagen Pectin Factory Ltd., of Little Skensved, Denmark, a subsidiary of Hercules Inc., of Wilmington, Delaware, U.S.A., has proposed its product Genuvisco Type 0819, an iota-carrageenan (i-carrageenan), as a possible thickener for toothpaste.

I-carrageenan available from Marine Colloids Division of FMC Corp. of Springfield, New Jersey, U.S.A., as Viscarin TP-5 has also been proposed for possible toothpaste use with toothpaste containing dicalcium phosphate or silica. Moreover, i-carrageenan has been disclosed as a thickener component together with k-carrageenan and alkali metal alginate for a dentifrice containing galactan galactose in Japanese Patent Publication 56 115711, published 11 September 1981, of Lion Dentifrice Ltd.

When a dentifrice dispenser which operates mechanically or by pressure differential is employed, conventional techniques of reducing thickening of dentifrice may not be fully satisfactory since compared with a dentifrice filled into a flexible tube, when a dispenser is used the dentifrice must be relatively thin during filling but regains its consistency and remains so during the periods of shipping, storage and use. In other words, the dentifrice after filling essentially regains the consistency had prior to the liquifying effect during shear filling for shipping, storage and use. Conventional gelling agent such as sodium carboxymethyl cellulose, hydroxyethyl cellulose or mixtures thereof may be desirably used for dentifrice containing alpha-alumina trihydrate polishing agent which is to be filled into a dispenser.However, when such a dentifrice contains a number of active ingredients, such as at least two sources of fluorine, a desensitising agent such as allantoin (C7H6N403) and a vasodilator agent such as pyridyl carbinol,

difficulties occur when the dentifrice is filled into a mechanically operated or pressure differential dispenser.

In particular, dentifrice may seep through the space between a rod and a piston which are used particularly in a mechanically operated dispenser and leakage will then occur at dispenser orifices. Further, the dentifrice ribbon extruded from a mechanically operated or pressure differential dispenser may be irregular or non-continuous. Since it is particularly desirable to prepare a dentifrice containing alpha-alumina trihydrate polishing agent which includes several active agents, such as those indicated above, due to compatibility of such materials with the polishing agent, an alternative gelling system was needed.

Unexpectedly from amongst alternative types of gelling agents a mixture of a cellulosic gelling agent and i-carrageenan provides an excellent dentifrice containing alpha-alumina trihydrate and several active ingredients which is to be filled into an extruded from a mechanical or pressure differential dispenser. It is noteworthy that xanthan has not been compatible with cellulosic gelling agents since it may contain cellulase.

It is an advantage of the present invention that a dentifrice is provided which is readily filled into an extrudable from a mechanically operated or pressure differential dentifrice dispenser.

In accordance with certain of its aspects, the present invention relates to a dentifrice in a mechanically operated or pressure differential dispenser comprising about 2080% by weight of an aqueous humectant vehicle, about 0.1-5% by weight of gelling agent mixture, about2075% by weight of alpha-alumina trihydrate polishing agent, sodium fluoride and sodium monofluorophosphate in amount to provide about 300 to 10000 ppm of fluorine, about 0.050.5% by weight of allantoin desensitising agent and about 0.050.5% by weight of pyridyl carbinol vasodilator agent, wherein said gelling agent mixture is a mixture of a cellulosic gelling agent or xanthan and i-carrageenan in a weight ratio either of cellulosic gelling or xanthan to i-carrageenan of about 5::1 to about 1:5.

In the dentifrice formulation the dental vehicle comprises a liquid phase proportioned with the gelling agent to form an extrudable creamy mass of desirable consistency. The liquid phase in the dentifrice will comprise chiefly water and humectant such as polyols including glycerine, sorbitol, maltitol, xylitol, low molecular weight polyethylene glycol (e.g. 400 or 600), propylene glycol or the like including suitable mixtures thereof. It is advantageous usually to use as the liquid phase water and a humectant such as glycerine, sorbitol or polyethylene glycol, typically in amounts of about 1055% by weight of water and about 2055% by weight of humectant.

The dentifrice contains alpha-alumina trihydrate polishing agent in amounts of about 2075% by weight. Alpha-alumina trihydrate is typically prepared by the Bayer process and used as particles below about 40 microns, principally about 3--20 microns, in size. Other polishing agents may be included such as insoluble sodium metaphosphate, dicalcium phosphate, calcined alumina, silica or calcium carbonate in minor amount with respect to alpha-alumina trihydrate.

The gelling agent mixture of the present invention is present in the dentifrice in an amount of about 0.15% by weight. It contains either a cellulosic gelling agent or xanthan mixed with i-carrageenan wherein the weight ratio of the said cellulosic gelling agent or xanthan to the said i-carrageenan is from about 5:1 to about 1:5, preferably from about 1:1 to about 1 :3, and the total gelling agent mixture is preferably about 0.23% by weight of the dentifrice.

As mentioned above, iota-carrageenan is commercially available as Genuvisco type 0819 and Viscarin TP-5 and has been recommended for use ins toothpaste. Such use in a toothpaste was described in Japanese Patent Publication 56 115711 of Lion Dentifrice Ltd., wherein i-carrageenan is mentioned as a possible component of a gelling system together with k-carrageenan and alkali metal alginate. In U.S.

Patent 4,353,890 to Scott, i-carrageenan is disclosed as an alternative to k-carageenan as a toothpaste gelling agent wherein the toothpaste is subjected to microwave radiation to reduce the tendency of carrageenan in general to become thin during manufacture. The carrageenan may be the sole gelling agent or mixed with other gelling agents. In the present invention, dentifrice containing i-carrageenan to be filled into a mechanically operated or pressure differential dispenser does not require microwave radiation.

The prior art generally discussed above does not indicate that gelling systems of cellulose gelling agent and i-carrageenan can provide dentifrices containing alpha-alumina trihydrate polishing agent and many active ingredients with the properties necessary for efficient filling into mechanically operated or pressure differential dispenser and extrusion therefrom.

It is noteworthy that U.S. Patent 4,029,760 to de Roeck et al., discloses an oral composition in which i-carrageenan is set forth as an antigingivitis agent alternative to other carrageenans. Carrageenins are highly depolymerised derivatives of carrageenans. Carrageenans do not appear two provide an antigingivitis effect.

Dentifrices are commonly manufactured by cold process, e.g. at about 25"C, or by a hot process, e.g. at about 60"C. I-carrageenan can be used in either cold process or hot process techniques. Since xanthan is made with cold processing, when it is employed, it may be readily mixed with i-carrageenan and incorporated together therewith in the dentifrice by cold processing. l-carrageenan can be used only with hot processing.

Physical properties of Genuvisco type 0819 i-carrageenan are indicated below: 1. Viscosity of 0.30% solution of Genuvisco type 0819 in lean soivent (high glycerine, low water) prepared using a hot process (60"C): Viscosity=110+17 cP at 32 rpm.

Viscosity=70+11 cP at 61 rpm.

Viscosity=45+7 cP at 128 rpm.

Measured on Haake Rotovisco RV3 at 25"C.

2. Viscosity of 0.30% solution of Genuvisco type 0819 in lean solvent prepared using a cold process (25 C).

Viscosity=450+60 cP measured on Brookfield Viscometer LVT at 25 C.

Viscosity=85+13 cP at 32 rpm.

Viscosity=558 cP at 64 rpm.

Viscosity=376 cP at 128 rpm.

Measured on Haake Rotovisco RV3 at 250C.

3. Particle size: Less than 1% gum on 0.075 mm test sieve (DIN 80,200 U.S. mesh).

4. Moisture content: Less than 12%.

5. pH: 8.5+1.5 in 0.5% solution in distilled water at 25 C.

6. Colour: White to cream.

Viscarin TP-5 i-carrageenan has the following physical properties: Colour: lighttan to tan; Particle size: more than 95.0% through a U.S. Standard Sieve, 250 nm (series #60).

Moisture: maximum 12.0% (Cenco Moisture Balance).

pH: 7.0 to 1.5% solution,30 C.

Typical desirable cellulosic gelling agents include alkali metal carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose and hydroxypropyl cellulose. Sodium carboxymethyl cellulose is preferred. The mixed gel system is present in amount of about 0.15% by weight of the dentifrice, and the weight ratio of cellulosic gelling agent to i-carrageenan is from about 5:1 to about 1:5, preferably about 1:1 to about 1:3 and most preferably about 1:1. Thus, a typical preferred dentifrice can contain about 0.91.2% total gelling agent including about 0.3-0.9% of each of cellulosic gelling agent and i-carrageenan, the weight ratio between the two being from about 1:1 to 1:3.

It is noteworthy that grades of sodium carboxymethyl cellulose which may be used include the following: TABLE 1 Supplier CMC Grade Viscosity Hercules 7MXF 300--500 Hercules 7MFD 300--500 Hercules 9M31F 900--1200 Hercules 9M31XF 901200 Hercules 12M31XF 900--1200 Hercules 7MF 30-500 Hercules 12M31PD 900--1200 Hercules 7M8SXF 200800 Wolff Walsrode Walocel CRT 1000 PA 07 700--1200 Nyma Nymcel ZMF.33* 50--80 Enka Akucell AC 1642 80--120 Enka Akucell AC 1632i 60120 Cros Cellogen HP-SA 700-900 Uddeholm Cekol MVEP 500--800 Hoechst Tylose CB 200* 1 2260 measured in 1.5% solution except: * 1% solution (Brookfield; 25 C).

** Hoeppler Viscometer (2%; 20 C).

Further, grades of hydroxyethyl cellulose which may be used include the following: TABLE 2 Supplier HEC Grade Viscosity Hercules Natrosol 250M and MR 4500--6500 Hercules Natrosol 250 HR 1500--2500 and250H Hercules Natrosol 250 HHR 3400--5000 and 250 HH BP Chemicals Cellobond 5000 A 4200--5600 BP Chemicals Cellobond 7000 A 6000--7000 Hoechst Tylose H 4000 P ~ 3000--5000 Hoechst Tylose H 10000 P* 700--1200 * 1% solution (Brookfield; 25"C).

** Hoeppler Viscometer (2%; 25*C).

The i-carrageenan and cellulosic gelling agent 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, with hot processing (typically about 60 C) or cold processing (typically about 25"C) techniques.

Xanthan gum is a fermentation product prepared by action of the bacteria of the genus Xanthomonas upon carbohydrates. Four species of Xanthomonas, viz X campetris, X phaseolei, X malvocearum and X carotae are reported in the literature to be the most efficient gum producers. Although the exact chemical structure is not determined, it is generally accepted to be a heteropolysaccharide with a molecular weight of several million. It contains D-glucose, D-mannose and D-glucuronic acid in the molar ratio of 2.8:3:2.0. The molecule contains 4.7% acetyl and about 3% pyruvate. The proposed chemical structure configuration can be found in McNeely and Kang, Industrial Guns, ed. R. L. Whistler, CH XXI, 2nd Edition, New York, 1973. The procedure for growing, isolating and purifying the xanthan gum is also found in that publication.Further description of xanthan gum is found in Manufacturing Chemist, May 1960, pages 205208 (including mention at page 208 of potential use of gums therein described for formulating toothpastes).

The i-carrageenan and xanthan 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, with cold processing (typically about 25 C) techniques.

The dentifrice is packaged in a container from which it can be readily extruded such as a pressure differential or mechanically operated dental cream dispenser. The rheological properties are highly desirable when a mechanically operated dispensing container of the type described in British Patent Application 2 070 695A, published 9 September 1981, is employed. This dispensing container comprises a dispensing mouthpiece, a tension member, a central rod, a piston and operating hand control. The disclosure ofthis published application is incorporated herein by reference.

Examples of pressure differential dispensing containers include the aerosol and vacuum type. Suitable pressure differential dispensers include those comprising a collapsible product-containing bag being disposed within a rigid container which contains a propellant fluid. In such dispensing containers, operation of the valve permits release of the product only, the propellant fluid being separated from the product by the fluid impermeable bag. Dispensers of this type are described in U.S. Patents 3,828,977 and 3,838,976.

These are so-called Sepro dispensers. So-called Exxel containers also utilise pressure.

Still another type dispenser is the barrier piston container described in U.S. 4,171,757. Such container includes a valve, a product-containing compartment and an essentially fluid-tight barrier piston which separates the propellant fluid from the contained product (the so-called Diamond container).

The dentifrice contains as active agents a mixture of sodium-fluoride and sodium monofluorophosphate to provide about 300--10000 ppm of fluorine, e.g. about 750--2000 ppm, and particularly about 1400--2000 ppm such as about 1 401 670 ppm. A binary fluoride system of sodium monofluorophosphate and sodium fluoride is desirably used in which about 3040% of the fluorine (e.g.

about3035%) is provided by sodium fluoride.

Sodium monofluorophosphate, Na2PO3F, 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 85%, and preferably at least 90% by weight of sodium monofluorophosphate 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 monoflijomphosphate employed should have a total fluoride content of above 12%, preferably above 12.7%, a content of not more than 1.5%, 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 fluorine-containing component from sodium monofluorophosphate. About 225800 ppm of fluorine is preferably provided to the dental cream by sodium fluoride.

Additional active agent is provided to the dentifrice by the presence of about 0.050.5% by weight, preferably about 0.00.2%, of ailantoin desensitising agent. Such agent combats sensitivity of wounded periodontal tissue and promotes its healing. Ailantoin can be obtained from ABM Industrial Products Ltd., of Woodley, Stockport, Cheshire, England.

Pyridyl carbinol active agent in an amount of about 0.050.5% by weight, preferably about 0.00.2%, provides the dentifrice with a vasodilator effect.

When a dentifrice containing alpha-alumina trihydrate polishing agent, the binary fluoride system, allantoin densensitising agent and pyridyl carbinol vasodilator agent, described above, is employed filling and extrusion using mechanically operated or pressure differential dispensers is made efficient and rheologically desirable with the gel system of the present invention.

Filling may be effected by conventional techniques. For instance, when a mechanically operated dispenser of the type described in published British Patent Application 2070 695A is used, a predetermined amount of the dentifrice is extruded through a nozzle to fill the dispenser which is open at its bottom and which contains a central rod. A piston having a diameter corresponding to the inner diameter of the dispenser and a central hole to permit insertion of the central rod therein is slid into place. The dispenser is then sealed with a bottom disc.

Any suitable surface active or detersive material may be included in the dentifrice compositions of the present invention. Such compatible materials are desirable to provide additional detersive, foaming and anti-bacterial 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, non ionic 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 (e.g. sodium coconut fatty acid monoglyceride monosulphate), higher alkyl sulphate (e.g. sodium lauryl sulphate), alkyl aryl sulphonate (e.g. 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 carbon atoms in the acyl radical.

The amino acid portion is derived generally from the lower aliphatic saturated monoaminocarboxylic acids having about 2 to 6 carbon atoms, usually the monocarboxylic acid compounds. Suitable compounds are the fatty acid amides of glycerine, sarcosine, alanine, 3-amino-propanoic acid and valine having about 12 to 16 carbon atoms in the acyl group. It is preferred to use the N-lauroyl, myristoyl and palmitoyl sarcoside compounds, however, for optimum effects.

The amide compounds may be employed in the form of the free acid or preferably as the water-soluble salts thereof, such as the alkali metal, ammonium, amine and alkyloiamine 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 refers to such compounds having a free carboxylic group or the water-soluble ca rboxylate salts.

Such materials are utiiised in pure or substantially pure form. They should be as free as practicable from soap or similar higher fatty acid material which tends to reduce the activity of these compounds. In usual practice, the amount of such higher fatty acid materials is less than 15% by weight of the amide and insufficient to substantially adversely affect it, and preferably less than about 10% of the said amide material.

Various other materials may be incorporated in the dentifrice of the present invention. Examples thereof are colouring or whitening agents, preservatives, such as methyl p-hydroxybenzoate, 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 of the present invention 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 5%, preferably about 0.05% to about 1.0%, by weight of the dentifrice composition include: N1-4 (chlorobenzyl-N5-(2,4-dichlorobenzyl) biguanide; p-chlorophenyl biguanide; 4-chlorobenz hydryl biguanide; 4-chlorobenz hydrylguanylurea; N-3-lauroxypropyl-N5-p-chlorobenzylbiguanide; 1,6di-p-chlornbenzylbiguanide; 1-(lauryidimethylammonium)-8-(p-chlorobenzyl-dimethyl-ammonium) octane dichloride; 5,6-dichloro-2-guanidinobenzimidazole; N1-p-chlorophenyl-Ns-lau rylbiguanide; 5-amino-i ,3-bis (2-ethyl hexyl)-5-methylhexa-hydropyrimidine; and their non-toxic acid addition salts.

Any suitable flavoring 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, e.g. 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 dentifrices should have a pH practicable for use. A pH range of 3 to 10.5 is particularly desirable.

The reference to the pH is meant to be the pH determination directly on the dentifrice. If desired, materials such as benzoic or citric acid may be added to adjust the pH to, say 4 to 8.5.

The invention may be put into practice in various ways and a number of specific embodiments will be described by way of example to illustrate the invention with reference to the accompanying examples. All amounts of the various ingredients are by weight unless otherwise specified.

EXAMPLES 1Ato 11 EXAMPLE 1A The following dentifrice is prepared by conventional room temperature cold process and filled into the mechanically operated dispenser described in British Patent Publication 2070 695A.

Parts Sorbitol (70% aqueous solution) 23.000 Sodium Saccharin 0.170 i-carrageenan (Genuvisco 0819) 0.500 Sodium Carboxymethyl cellulose (7MFD) 0.500 Methyl p-hydroxybenzoate 0.080 Allantoin 0.150 Sodium Fluoride 0.100 Sodium Monofluorophosphate 0.760 Pyridyl Carbinol 0.100 Alpha alumina trihydrate (Alcoa C-333) 51.000 Benzoic Acid 0.140 Sodium Lauryl Sulphate 1.667 Titanium Dioxide 0.500 Flavour 1.200 Deionised water 20.133 The dentifrice fills efficiently into the dispenser and does not undergo leakage during storage at 43"C for over 1 month. It extrudes well from the dispenser after 1 month storage at 43 C.

Similar satisfactory results are attained when the dentifrice is modified to contain 0.55 parts of each of i-carrageenan and sodium carboxymethyl cellulose in one case (Example 1 B) and 0.45 parts of each of i-carrageenan and sodium carboxymethyl cellulose in a second case (Example 1 C), with corresponding adjustment of the water contents. Indeed absence of leakage and good extrudibility after storage at 43"C for 3 months are observed with these dentifrices.

Again satisfactory results are observed when each of the three dentifrices described above are modified to contain 50.000 parts of alpha-alumina trihydrate in one set of these dentifrices (Examples 1 D, E and F) and 52.000 parts of alpha-alumina trihydrate in the second set of three dentifrices (Examples 1 G, H and 1), with corresponding adjustment of the water contents.

EXAMPLES 2Ato 2D EXAMPLE 2A The following dentifrice is prepared by cold process and filled into the same dispenser as in Example 1.

Parts Sorbitol (70% aqueous solution) 23.000 Sodium Saccharin 0.170 i-carrageenan (Genuvisco 0819) 0.666 Sodium carboxymethyl cellulose (7MFD) 0.334 Methyl p-hydroxybenzoate 0.080 Allantoin 0.150 Sodium Fluoride 0.100 Sodium Monofluorophosphate 0.760 Pyridyl carbinol 0.100 Alpha alumina trihydrate (Alcoa C-333) 51.500 Benzoic Acid 0.140 Sodium lauryl sulphate 1.667 Titanium Dioxide 0.500 Flavour 1.200 Deionised water 19.633 The dentifrice fills efficiently into the dispenser and does not undergo leakage and extrudes well from the dispenser after storage for 1 month at 43*C.

Similar desirable effects are attained when the dentifrices of the examples are filled into a pressure differential dispenser.

When sodium carboxymethyl cellulose is used as the only gelling agent (Example 2B) poor extrusion occurs. When hydroxyethyl cellulose is used as the only gelling agent (Example 2C) leakage occurs.

However, when hydroxyethyl cellulose is mixed with i-carrageenan (Example 2D) desirable filling and extrusion is attained.

EXAMPLES 3A to 3R EXAMPLE 3A The following dentifrice is prepared by conventional room temperature cold process and filled into the mechanically operated dispenser in British Patent Publication 2 070 695A.

Parts Sorbitol (70% aqueous solution) 23.000 Sodium Saccharin 0.170 i-carrageenan (Genuvisco 0819) 0.500 Xanthan (Keltrol) 0.500 Methyl p-hydroxybenzoate 0.080 Allantoin 0.150 Sodium Fluoride 0.100 Sodium Monofluorophosphate 0.760 Pyridyl Carbinol 0.100 Alpha alumina trihydrate (Alcoa C-333) 51.000 Benzoic Acid 0.140 Sodium Lauryl Sulphate 1.667 Titanium Dioxide 0.500 Flavour 1.200 Deionised water 20.133 The dentifrice fills efficiently into the dispenser and does not undergo leakage during storage at 43"C for over 1 month. It extrudes well from the dispenser after 1 month storage at 43*C.

Similarly satisfactory results are attained when the dentifrice is modified to contain 0.55 parts of each of i-carrageenan and xanthan in one case (Example 3B) and 0.45 parts of each of i-carrageenan and xanthan in a second case (Example 3C), with corresponding adjustment of the water contents. Indeed absence of leakage and good extrudibility after storage at 43 C.

EXAMPLES 1Ato 1H The following dentifrices are prepared by conventional hot process at 60 C.

Parts A B C Glycerine 22.00 22.00 22.00 Sodium carboxymethyl cellulose (7MF) 1.00 - 0.30 I-Carrageenan (Genuvisco 0819) - 0.96 0.60 Sodium saccharin 0.20 0.20 0.20 Sodium benzoate 0.50 0.50 0.50 Sodium monofluomphosphate 0.76 0.76 0.76 Tetrasodium pyrophosphate 0.25 0.25 0.25 Dicalcium phosphate dihydrate 48.76 48.76 48.76 Sodium lauryl sulphate 1.20 1.20 1.20 Flavour 0.84 0.84 0.84 Deionized water 24.49 24.59 24.59 Each dentifrice is filled into the mechanically operated dispenser described in British Patent Publication No.2070 695A and the yield point viscosities determined in a Haake Rotovisco Viscometer using a profiled SV IIP cup initially (2 days following preparation), and after ageing for periods at room temperature.The results are as follows: Example Initial 2 weeks 1 month 3 months 1A 4380 5030 5760 7080 1B 3190 3370 3610 1C 3190 2420 2610 2970 Pyridyl Carbinol 0.100 Alpha alumina trihydrate (Alcoa C-333) 51.000 Benzoic Acid 0.140 Sodium Lauryl Sulphate 1.667 Titanium Dioxide 0.500 Flavour 1.200 Deionised water 20.133 The dentifrice fills efficiently into the dispenser and does not undergo leakage and extrudes well from the dispenser after storage for 3 months at 43 C.

Similar desirable results are attained with 50.000 parts of alpha-alumina trihydrate (Example 4B). Each variant also provides similar results with a gel system containing (a) 0.825 parts of i-carrageenan and 0.275 parts of xanthan (Examples 4C and 4D), and (b) 0.675 parts of i-carrageenan and 0.225 parts of xanthan (Examples 4E and 4F). Similar desirable effects are attained when the dentifrices of the examples are filled into a pressure differential dispenser.

It will be apparent to those skilled in the art that further modifications of the examples illustrative of the invention, may be made thereto.

Claims (11)

1. A dentifrice comprising about 2C#80% by weight of an aqueous humectant vehicle, about 0.15% by weight of gelling agent mixture, about 275% by weight of alpha-alumina trihydrate polishing agent, sodium fluoride and sodium monofluorophosphate in amount to provide about 300 to 10000 ppm of fluorine, about 0.050.5% by weight of allantoin desensitising agent and about 0.050.5% by weight of pyridyl carbinol vasodilator agent, wherein the said gelling agent mixture is a mixture either of a cellulosic gelling agent or xanthan with i-carrageenan in a weight ratio of cellulosic gelling agent or xanthan to i-carrageenan of about 5:1 to about 1:5.

2. A dentifrice as claimed in Claim 1, in which the weight ratio of the said cellulosic gelling agent or of the said xanthan to the said i-carrageenan is about 3:1 to about 1:3.

3. A dentifrice as claimed in Claim 1 or Claim 2, in which the gelling agent mixture is present in amount of about 0.23% by weight.

4. A dentifrice as claimed in Claim 1,2 or 3, in which the said cellulosic gelling agent is present and is sodium carboxymethyl cellulose.

5. A dentifrice as claimed in Claim 1,2 or 3, in which the said xanthan is present.

6. A dentifrice as claimed in any one of Claims 1 to 5, in which the weight ratio of the said cellulosic gelling agent or of the said xanthan to the said i-carrageenan is about 1:1.

7. A dentifrice as claimed in any one of Claims 1 to 6, in which the said sodium fluoride and the said sodium monofluorophosphate are present in amount to provide about 7502000 ppm of fluorine and about 3040% of the fluorine is provided by the said sodium fluoride.

8. A dentifrice as claimed in Claim 1, substantially as specifically described herein with reference to any one of Examples 1Ato 11, 2A, 2D, 3Ato 3R or 4A to 4F.

9. A dentifrice as claimed in any one of Claims 1 to 8, in which the said dentifrice is contained in a mechanically operated dispenser.

10. A dentifrice as claimed in any one of Claims 1 to 8, in which the dentifrice is contained in a pressure differential dispenser.

11. A process for preparing a dispenser containing a dentifrice comprising about 2080% by weight of an aqueous humectant vehicle, about 0.15% by weight of gelling agent mixture, about 2075% by weight of alpha alumina trihydrate polishing agent, sodium fluoride and sodium monofluorophosphate in amount to provide about 300 to 1000 or 10000 ppm of fluorine, about 0.050.5% by weight of allantoin desensitising agent and about 0.050.5% by weight of pyridyl carbinol vasodilator agent, wherein said gelling agent mixture is a mixture of a cellulosic gelling agent and i-carrageenan in a weight ratio of cellulosic gelling agent to i-carrageenan of about 5:1 to about 1: :5 which comprises extruding into a mechanically operated dispenser a predetermined amount of the said dentifrice through a nozzle to fill a dispenser which is open at its bottom and which contains a central rod, sliding into place around the said central rod a piston having a diameter corresponding to the inner diameter of the dispenser and a central hole to receive the said central rod and then sealing the said dispenser with a bottom disc.