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WO2005067876A1 - Compositions de dentifrice - Google Patents

Compositions de dentifrice Download PDF

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Publication number
WO2005067876A1
WO2005067876A1 PCT/EP2005/000105 EP2005000105W WO2005067876A1 WO 2005067876 A1 WO2005067876 A1 WO 2005067876A1 EP 2005000105 W EP2005000105 W EP 2005000105W WO 2005067876 A1 WO2005067876 A1 WO 2005067876A1
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WO
WIPO (PCT)
Prior art keywords
silica
abrasive
range
aluminosilicate
weight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2005/000105
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English (en)
Inventor
Abraham Araya
Jonathan Edward Creeth
Ian Patrick Mckeown
Peter William Stanier
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Glaxo Group Ltd
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Glaxo Group Ltd
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Publication date
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Publication of WO2005067876A1 publication Critical patent/WO2005067876A1/fr
Anticipated expiration legal-status Critical
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K8/00—Cosmetics or similar toiletry preparations
    • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
    • A61K8/19—Cosmetics or similar toiletry preparations characterised by the composition containing inorganic ingredients
    • A61K8/26—Aluminium; Compounds thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K8/00—Cosmetics or similar toiletry preparations
    • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
    • A61K8/19—Cosmetics or similar toiletry preparations characterised by the composition containing inorganic ingredients
    • A61K8/25—Silicon; Compounds thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
    • A61Q11/00—Preparations for care of the teeth, of the oral cavity or of dentures; Dentifrices, e.g. toothpastes; Mouth rinses
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K2800/00—Properties of cosmetic compositions or active ingredients thereof or formulation aids used therein and process related aspects
    • A61K2800/20—Chemical, physico-chemical or functional or structural properties of the composition as a whole
    • A61K2800/28—Rubbing or scrubbing compositions; Peeling or abrasive compositions; Containing exfoliants

Definitions

  • This invention relates to dentifrice compositions for use in high cleaning, controlled abrasivity compositions and in particular to an abrasive system comprising a combination of amorphous silica and crystalline aluminosilicate.
  • Dentifrices commonly incorporate an abrasive material for mechanical cleaning and polishing of teeth by physical abrading deposits and they may also include a chemical cleaning agent.
  • the abrasive material is primarily intended to effect mechanical removal of deposits from the surface of teeth, e.g. removal of pellicle film adhered to the tooth surface.
  • Pellicle film is prone to discolouration and staining, e.g. by comestibles such as tea and coffee, and by tars and particulates in exhaled cigarette smoke, resulting in an unsightly appearance of the teeth. While such mechanical removal is important for effective cleaning, it is vital that the abrasive used is not unduly harsh in order to minimise damage, e.g. scratching, to the teeth.
  • Synthetically produced amorphous silicas are often the favoured abrasive component in dentifrices and can be readily tailored during the production process to possess predetermined abrasive and other physical characteristics appropriate for use in dentifrices.
  • Precipitated silicas are particularly useful as abrasive components and are generally the material of choice in dentifrice compositions.
  • silicas are particularly effective for mechanical cleaning by abrasion, they make no significant contribution in terms of chemical cleaning.
  • Crystalline aluminosilicates have been used as cleaning agents in dentifrice compositions. They possess a mechanical cleaning action (abrasivity) and are also known to bind calcium ions. Desirably, a dental cleaning agent combines relatively good cleaning with minimal abrasion of dentine. It has been found that most available zeolites are too abrasive to provide adequate cleaning without unacceptable abrasion. There remains a need for formulations with improved cleaning without increased abrasivity, beyond what may be achieved with silicas alone. Surprisingly, it has now been found that the use of a combination of a particular silica or silicas with a specific aluminosilicate can result in a dentifrice composition having good cleaning with acceptable abrasion characteristics.
  • a dentifrice composition comprising an abrasive system comprising a combination of at least one abrasive amorphous silica having a Radioactive Dental Abrasion (RDA) in the range 30 to 300, an oil abso ⁇ tion in the range 40 to 150 cm 3 / 100 g and a weight mean particle size in the range 3 to 15 ⁇ m and a crystalline aluminosilicate having an average crystallite size below 0.2 ⁇ m plus an orally acceptable carrier.
  • RDA Radioactive Dental Abrasion
  • the components of the system of this invention are characterised by defined RDA values which are measured using an aqueous slurry of the component as defined hereinafter. If however the RDA were measured on the complete dentifrice composition i.e. including any optional components as defined hereinafter, the RDA values obtained may be significantly different.
  • the RDA of a toothpaste incorporating the materials of the invention would be in the range 25-200, preferably 30-180, more preferably 50-150.
  • abrasive silica(s) will depend on the abrasiveness of the silicas employed. Usually the abrasive silica(s) content will be in the range of 7 to 85% , e.g. 12 to 80% , by weight of the combined silica abrasive/aluminosilicate content of the system.
  • the silica may be an abrasive amorphous silica (herein referred to as silica A) having a Radioactive Dental Abrasion (RDA) in the range 30 to 150, an oil abso ⁇ tion in the range 60 to 140 cm 3 / 100 g and a weight mean particle size in the range 5 to 15 ⁇ m and/or an abrasive amo ⁇ hous silica (herein referred to as silica B) having a Radioactive Dental Abrasion (RDA) in the range 100 to 300, an oil abso ⁇ tion in the range 40 to 150 cm 3 / 100 g and a weight mean particle size in the range 3 to 15 ⁇ m.
  • silica A abrasive amorphous silica
  • RDA Radioactive Dental Abrasion
  • silica B having a Radioactive Dental Abrasion (RDA) in the range 100 to 300
  • silica B functions as a "cleaning booster" while silica A, relative to silica B, constitutes the principal silica content of the abrasive system.
  • the abrasive system of the present invention may also include a thickening silica having an RDA less than 30.
  • silica(s) employed in the abrasive system is/are precipitated silicas.
  • the components of the abrasive system of the invention are preferably in the dry state to ensure a free flowing powder with no microbial and preservation issues associated with filter cakes with high water content.
  • the physical water content as measured by loss at 105 °C associated with the system and/or its individual components is preferably less than 20% of the system or individual component.
  • silica A has a low to medium RDA. Typically its RDA is at least 40, more usually at least 50. Typically its RDA is no greater than 130, e.g. no greater than 110.
  • silica A The oil abso ⁇ tion of the silicas employed in the present invention are measured according to the test described hereinafter.
  • the preferred range for silica A is 80 to 120 cm 3 / 100 g.
  • silica A has a weight mean particle size in the range 6 to 12 ⁇ m, the size being measured by a Malvern Mastersizer * , as described hereinafter.
  • the desired particle size of silica A is obtained by subjecting the silica to a milling step.
  • silica B has a medium to high RDA. Typically its RDA is at least 100, more usually at least 120, e.g. at least 130. Typically its RDA is no greater than 220, more usually no greater than 200, e.g. no greater than 180.
  • the oil abso ⁇ tion of silica B is typically at least 50, more usually at least 60, e.g. at least 65 cmVlOOg.
  • the oil abso ⁇ tion of silica B is typically at most 130, more usually at most 120, e.g. at most 100 cmVlOOg. Where both silica A and B are present in the system, usually silica B will have the lower oil abso ⁇ tion.
  • silica B has a weight mean particle size of at least 2 ⁇ m, more usually at least 3 m.
  • silica B has a weight mean particle size of at most 8 ⁇ m, more usually at most 6 ⁇ m, as measured by a Malvern Mastersizer ® .
  • the desired particle size of silica B is obtained by subjecting the silica to a micronising comminution step.
  • the pHs of the silicas A and B are typically at most 8, more usually at most 7.5, e.g. at most 7.0.
  • the pHs of silicas A and B are at least 3.0 and more usually at least 4.0.
  • the pH of the abrasive system is a particularly effective way of controlling the pH of the dentifrice composition employing the system. According to a feature of the invention, the components of the abrasive system are selected in such a way that the pH of the system is at most 10.0, more usually at most 9.5, e.g. at most 9.0.
  • Such pH control may be effected by the silica content (silica A and/or B and any other silica present) of the system without the need for adjusting the inherent, high pH of the crystalline aluminosilicates by ion exchange techniques.
  • silica content sica A and/or B and any other silica present
  • the amount of water present on the amo ⁇ hous silicas A or B, as measured by the ignition loss at 1000° C, is usually up to 25 per cent by weight and preferably up to 15 per cent by weight. Usually the ignition loss at 1000° C is more than 4 per cent by weight.
  • Crystalline aluminosilicates useful in this invention can be represented by the formula: M 2/n O . Al 2 O 3 . xSiO 2 . yH 2 O wherein M represents a metal moiety, said metal having a valency of n, x indicates the molar ratio of silica to alumina and y indicates the ratio of molecules of water to alumina.
  • M represents a metal moiety
  • x indicates the molar ratio of silica to alumina
  • y indicates the ratio of molecules of water to alumina.
  • the structure and characteristics of many crystalline aluminosilicates (zeolites) are described in the standard work "Zeolite Molecular Sieves" by Donald W. Breck, published by Robert E. Krieger Publishing Company.
  • the value of x in the above empirical formula is in the range 1.5 to 10.
  • the value of y which represents the amount of water contained in the voids of the zeolite, can vary widely. In anhydrous material
  • Zeolites useful in this invention may be based on naturally-occurring or synthetic aluminosilicates but a preferred form of zeolite has the structure known as zeolite P.
  • Particularly preferred forms of zeolite are those disclosed in EP-A-0 384 070, EP-A-0 565 364, EP-A-0 697 010, EP-A-0 742 780, WO-A-96/14270, WO-A-96/34828 and WO-A- 97/06102, the entire- contents of which are inco ⁇ orated herein by this reference.
  • the zeolite P described in EP-A-0 384 070 has the empirical formula given above in which M represents an alkali metal and x has a value up to 2.66, preferably in the range 1.8 to 2.66, and has a structure which is particularly useful in the present invention. More preferably, x has a value in the range 1.8 to 2.4.
  • the zeolite P disclosed in the above patent literature is readily amenable to being produced with crystallite sizes well below 0.2 ⁇ m and agglomerate sizes (i.e. weight mean particle sizes) below 2.5 ⁇ m, even when dried to a moisture content below 20% by weight. This contrasts with other zeolites which, on drying, tend to agglomerate to large weight mean particle sizes.
  • the average crystallite size of the crystalline aluminosilicate, measured using the test described hereinafter is preferably between 0.01 and 0.1 ⁇ m (typically less than 0.1 ⁇ m) and, more preferably 0.02 to 0.08 ⁇ m.
  • the RDA of the crystalline aluminosilicate should be relatively low and is preferably less than 120, more preferably less than 100. Its RDA will usually be in excess of 30.
  • preferred aluminosilicates produce minimal scratching on dental surfaces when used. Scratching can be assessed using the PAV test described hereinafter and preferred aluminosilicates have a PAN of 4 to 11 , preferably 4 to 9 and more preferably 4 to 7.
  • the aluminosilicate preferably has a calcium binding capacity, as hereinafter defined, of at least 100 mg CaO per gram of anhydrous aluminosilicate, preferably at least 130 mg CaO per gram of anhydrous aluminosilicate and most preferably at least 150 mg CaO per gram of anhydrous aluminosilicate.
  • the aluminosilicate preferably has an oil abso ⁇ tion of at least 40 cm 3 / 100 g and preferably in the range 40 to 100 cm 3 / 100 g.
  • the aluminosilicate preferably has a weight mean particle size as measured by Malvern Mastersizer" , of at least 0.5 ⁇ m, more usually at least 1.0 ⁇ m, e.g. at least 1.8 ⁇ m.
  • the aluminosilicate preferably has a weight mean particle size as measured by Malvern Mastersizer * , of at most 10.0 ⁇ m, more usually at most 5.0 ⁇ m, e.g. at most 3.0 ⁇ m.
  • a most preferred range for the aluminosilicate is from 2.0 to 2.5 ⁇ m.
  • the preferred form of zeolite P is one in which M in the above formula consists of alkali metal ions.
  • suitable forms of zeolite P include those wherein a proportion of the alkali metal moieties M has been exchanged for other metal moieties, for instance as disclosed in published International Patent Application No. WO 01/94512.
  • Partially exchanged zeolites are particularly useful when it is desired to control the pH of the abrasive system.
  • Such pH adjustment step involves additional processing of the zeolite and associated cost. For this reason, as mentioned above, it is preferred to buffer the effect of the high pH zeolite by means of the silica content of the abrasive system and the inherent pH of the selected silica(s).
  • the pH of the aluminosilicate used in the abrasive system of the invention is usually in excess of 10. Where the aluminosilicate present in the system is one which has undergone such ion exchange, its pH will usually be no greater than 10.
  • the proportions of silica and aluminosilicate present in the dental abrasive system of the invention can be varied in order to achieve a balance of properties suitable for the dentifrice composition in which it is used.
  • silica A is the only silica abrasive present in the abrasive system of the invention, it typically comprises at least 15% , more usually at least 20% , e.g. at least 30% , by weight of the combined silica abrasive/aluminosilicate content of the system.
  • silica A typically comprises at most 85% , more usually at most 80% , e.g. at most 70% , by weight of the combined silica abrasive/aluminosilicate content of the system.
  • a typical range for the silica A content is between 40 and 60% by weight of the combined silica abrasive/aluminosilicate content of the system.
  • silica B is the only silica abrasive present in the abrasive system of the invention, it typically comprises at least 1 % , more usually at least 5 %, e.g. at least 10%, by weight of the combined silica abrasive/aluminosilicate content of the system.
  • silica B typically comprises at most 70% , more usually at most 50%, e.g. at most 40% , by weight of the combined silica abrasive/aluminosilicate content of the system.
  • a typical range for the silica B content is between 15 and 35% by weight of the combined silica abrasive/aluminosilicate content of the system.
  • silica A typically comprises at least 25%, more usually at least 35%, e.g. at least 40%, by weight of the combined silica A/silicaB/aluminosilicate content of the system.
  • Silica B typically comprises at least 2%, more usually at least 4% , e.g. at least 10% , by weight of the combined total silica A/silicaB/aluminosilicate.
  • silicas A and B typically comprise at most 80%, more usually at most 70%, e.g. at most 65%, by weight of the combined silica abrasive/aluminosilicate content of the system.
  • a further additional component can be a different crystalline aluminosilicate, e.g. an A, X or Y type zeolite, which acts as a cleaning booster (hereinafter referred to as "booster zeolite").
  • booster zeolite crystalline aluminosilicate
  • the amount of booster zeolite present will usually be less than that of the crystalline aluminosilicate referred to hereinbefore (the "principal" zeolite).
  • a booster zeolite it is not necessary to include silica B in the abrasive system.
  • the booster zeolite preferably has an RDA in the range 100 to 300 and more preferably in the range 100 to 250.
  • the PAV of the booster zeolite is preferably in the range 9 to 25 and more preferably in the range 9 to 20.
  • the values for both the RDA and the PAV of the booster zeolite will be greater than those for the principal zeolite.
  • the preferred oil abso ⁇ tion of the booster zeolite is in the range 30 to 100 cm 3 /100 g, more preferably 30 to 50 cm 3 / 100 g.
  • the weight mean particle size of the booster zeolite is preferably in the range 2.0 to 5.0 ⁇ m.
  • the booster zeolite preferably has an average crystallite size above 0.2 ⁇ m and most preferably above 1.0 ⁇ m.
  • the proportions of silica A and silica B or booster zeolite present in the dental abrasive system of the invention can be varied to provide optimum cleaning with controlled abrasion.
  • the proportion of silica A to booster particles by weight is in the range 100 : 0 to 0 : 100.
  • the ratio is in the range 90 : 10 to 50 : 50.
  • booster particles refers to booster silica, B, booster zeolite or a combination of booster silica and booster zeolite.
  • the components of the system may be mixed prior to combining the subsequent mixture with the other components of the dentifrice composition or may be separately added to the other components of the dentifrice composition.
  • the components or mixture thereof will, at least prior to combining the same with other components of the dentifrice composition, usually be in the form of a substantially dry free flowing paniculate material.
  • a dentifrice composition containing the abrasive system according to the present invention may also include a fluoride ion source as protection against demineralisation by bacteria (caries) and/or acidic components of the diet (erosion).
  • the fluoride ion source may be provided by any of the compounds conventionally used in toothpastes for these pu ⁇ oses, e.g. sodium fluoride, alkali metal monofluorophosphate, stannous fluoride and the like, with an alkali metal monofluorophosphate such as sodium monofluorophosphate being preferred.
  • the fluoride ion source serves in a known manner for caries protection.
  • the fluoride ion source will be used in an amount to provide a safe yet effective amount to provide an anti-caries and anti-erosion benefit such as an amount sufficient to provide from about 25 ppm to about 3500 ppm, preferably about 1100 ppm, as fluoride ion.
  • the formulation may contain 0.1 - 0.5 wt % of an alkali metal fluoride such as sodium fluoride.
  • the pH of the dentifrice composition inco ⁇ orating an abrasive system of the present invention is from about 6 to 10.5, more preferably from about 7 to about 9.5.
  • the composition may contain sodium hydroxide, e.g. up to 1.0 wt. % or more to provide a suitable pH.
  • the abrasive system of the present invention may be inco ⁇ orated in an orally acceptable carrier to produce a dentifrice composition.
  • orally acceptable carrier means a suitable vehicle which can be used to apply the resulting dentifrice composition to the oral cavity in a safe and effective manner.
  • the orally acceptable vehicle may be of a generally conventional composition e.g. comprising a thickening agent, a binding agent and a humectant.
  • Preferred binding agents include for example natural and synthetic gums such as xanthan gums, carageenans, alginates, cellulose ethers and esters.
  • Preferred humectants include glycerin, sorbitol, propylene glycol and polyethylene glycol.
  • a preferred humectant system consists of glycerin, sorbitol and polyethylene glycol.
  • the orally acceptable vehicle may optionally comprise one or more surfactants, sweetening agent, flavouring agent, anticaries agent (in addition to the fluoride ion source), anti-plaque agent, anti-bacterial agent such as triclosan or cetyl pyridinium chloride, tooth desensitizing agent such as potassium or strontium salts such as potassium nitrate or strontium chloride, colouring agents and pigment.
  • useful surfactants include the water-soluble salts of alkyl sulphates having from 10 to 18 carbon atoms in the alkyl moiety, such as sodium lauryl sulphate, but other anionic surfactants as well as non-ionic, zwitterionic and cationic surfactants may also be used.
  • the dentifrice composition suitably contains from about 10 to about 80 wt % humectant such as sorbitol, glycerin, polyethylene glycol or xylitol; from about 0.25 to about 5 wt % detergent; from 0 to about 2 wt % sweetener; from 0 to about 2 wt % flavouring agents; together with water and an effective amount of binding and thickening agents, such as from about 0.1 to about 15 wt % , to provide the toothpaste of the invention with the desired stability and flow characteristics.
  • humectant such as sorbitol, glycerin, polyethylene glycol or xylitol
  • the abrasive systems of the invention are capable of providing dentifrice compositions with good cleaning and are well within the abrasion limits generally considered as acceptable for commercial formulations.
  • the cleaning ability of a composition can be assessed by the test known as the FT 100 Cleaning test, details of which are given below.
  • the abrasive systems are tested in a dentifrice composition having a standard formulation.
  • Preferred abrasive systems of this invention have an FT I00 Cleaning value of at least 50 per cent, preferably at least 65 per cent and most preferably above 75 per cent.
  • RDA Radioactive Dentine Abrasion Test
  • the procedure follows the method for assessment of dentifrice abrasivity recommended by the American Dental Association (Journal of Dental Research 55(4) 563, 1976).
  • extracted human teeth are irradiated with a neutron flux and subjected to a standard brushing regime.
  • the radioactive phosphorus 32 removed from the dentin in the roots is used as the index of the abrasion of the dentifrice tested.
  • a reference slurry containing 10 g of calcium pyrophosphate in 50 cm 3 of 0.5% aqueous solution of sodium carboxymethyl cellulose is also measured and the RDA of this mixture is arbitrarily taken as 100.
  • a suspension of 10.0 g of the silica or aluminosilicate in 50 cm 3 of 0.5% aqueous solution of sodium carboxymethyl cellulose is prepared and the suspension is submitted to the same brushing regime.
  • a test slurry is prepared from 25 g dentifrice composition and 40 cm 3 of water and this slurry is submitted to the same brushing regime.
  • Aluminosilicate 2.5g Glycerol 10.0 g Sorbitol Syrup* 23.0 g *Syrup contains 70% sorbitol/30% water
  • the test is carried out using a modified Wet Scrub Abrasion Tester produced by Sheen Instruments.
  • the modification is to change the holder so that a toothbrush can be used in place of a paintbrush.
  • a weight of 400 g is attached to the brush assembly, which weighs 145 g, to force the brush onto the PERSPEX sheet.
  • the toothbrush has a multi-tufted, flat trim nylon head with round ended filaments and medium texture, for example, the well-known Professional Mentadent P gum health design, or an equivalent toothbrush.
  • a galvanometer is calibrated using a 45° Plaspec gloss head detector and a standard (50% gloss) reflecting plate. The galvanometer reading is adjusted to a value of 50 under these conditions.
  • the reading of the fresh PERSPEX sheet is then carried out using the same reflectance arrangement.
  • the fresh piece of PERSPEX sheet is then fitted into a holder. 2 cm 3 of the dispersed aluminosilicate, sufficient to lubricate fully the brushing stroke, is placed on the sheet and the brush head is lowered onto the sheet.
  • the machine is switched on and the sheet is subjected to 300 strokes of the weighted brush head.
  • the sheet is removed from the holder and all the suspension is washed off. It is then dried and its gloss value is determined again.
  • the abrasion value is the difference between the unabraded gloss value and the gloss value after abrasion. This test procedure, when applied to known abrasives, gave the following typical values.
  • PAV Calcium carbonate (15 ⁇ m) 32 Silica xerogel (10 ⁇ m) prepared according to 25 GB 1 262 292 Alumina trihydrate (Gibbsite) (15 ⁇ m) 16 Calcium pyrophosphate (10 ⁇ m) 14 Dicalcium phosphate dihydrate (15 ⁇ m) 7
  • the oil absorption is determined by the ASTM spatula rub-out method (American Society of Test Material Standards D 281). The test is based on the principle of mixing linseed oil with the silica or aluminosilicate by rubbing with a spatula on a smooth surface until a stiff putty-like paste is formed which will not break or separate when it is cut with a spatula.
  • Weight Mean Particle Size by Malvern Mastersizer * The weight mean particle size of the silica or aluminosilicate is determined using a Malvern Mastersizer * model S, with a 300 RF lens and MS 17 sample presentation unit. This instrument, made by Malvern Instruments, Malvern, Worcestershire, uses the principle of Fraunhofer diffraction, utilising a low power He/Ne laser. Before measurement, the sample is dispersed ultrasonically in water for 5 minutes (in the case of silica) and 30 seconds (in the case of aluminosilicate) to form an aqueous suspension. The Malvern Mastersizer * measures the weight particle size distribution of the silica or alumninosilicate. The weight mean particle size (d 50 ) or 50 percentile and the percentage of material below any specified size are easily obtained from the data generated by the instrument.
  • the average crystallite size is determined from photographs made in a scanning electron microscope.
  • the crystalline aluminosilicate is dried to a water content of about 1 to 3 weight per cent and the agglomerates are broken up with a pestle and mortar. From the photographs, a sufficient number of crystals, e.g. 100, is counted and their size measured to determine a statistically significant average (arithmetical mean) size.
  • the aluminosilicate is first equilibrated to constant weight over saturated sodium chloride solution and the water content is measured. An amount is dispersed in 1 cm 3 water in an amount corresponding to 1 g dm "3 (dry weight) and the resulting dispersion is injected into a stirred solution of total volume 54.923 cm 3 , consisting of 0.01M NaCl solution (50 cm 3 ) and 0.05M CaCl 2 (3.923 cm 3 ). This corresponds to a concentration of 200 mg of CaO per dm 3 , i.e. just greater than the theoretical maximum amount (197 mg) that can be taken up by an aluminosilicate of Si : Al ratio 1.00.
  • the dispersion is vigorously stirred at a temperature of 25° C for 15 minutes, after which time the Ca 2+ ion concentration is determined using a calcium electrode.
  • the Ca 2+ ion concentration measured is subtracted from the initial concentration to give the effective calcium binding capacity of the aluminosilicate sample
  • the quantities A, B and C are determined by the abrasive system under test.
  • the quantity of thickening silica ("D") is adjusted to ensure that the cohesion of the paste, as measured by the toothpaste cohesion test defined hereinafter is in the range 150 to 430 g.
  • a substrate consisting of highly polished 17 mm sintered, pure hydroxyapatite (HAP) discs is prepared.
  • the discs are polished using a Buehler rotary grinder and P600 wet paper, followed by P1200 lapping paper to give a mirror-like finish to simulate enamel tooth surface.
  • the whiteness of the discs (using the CIE 1976 L*a*b* system) before cleaning, L* (clean), is then measured using a Minolta Chroma-meter CR200, which has been calibrated against a standard calibration tile.
  • a fresh staining solution is prepared by mixing 50g of a 0.5% by weight solution of tannic acid and 50g of a 0.5% by weight solution of ammonium ferric sulphate to form a fresh colloidal iron (III) tannic acid complex ("ferric tannate"), which has a dark colour.
  • the fresh mixture is painted onto the HAP discs using a fine squirrel-hair brush and gently dried with a warm hairdryer.
  • Toothpaste Slurry Preparation A diluent is prepared, which consists of: % by weight
  • the toothpaste under test is weighed into a plastic beaker and mixed with diluent and demineralised water in the following proportions by weight: Toothpaste 33.3 %; Diluent 33.3 %; Water 33.3 % to produce a lOOg toothpaste slurry preparation, which is mixed for one minute with a high shear Heidolph mixer at 4000 r.p.m.
  • the toothpaste slurry is prepared immediately prior to carrying out the test to avoid any chances of settlement.
  • the stained HAP discs are then mounted horizontally in the bottom of a trough containing the toothpaste slurry under test and 263 g weighted Mentadent P Professional soft-nylon flat trim toothbrush heads are oscillated over the disc surfaces using a mechanical scrubbing machine (modified Martindale abrasion tester). An oscillation rate of 150 cycles per minute is used.
  • the toothbrush heads are 34-tuft flat-trim 0.2 mm bristle nylon heads and are weighted via weights loaded onto vertical spindles mounted in linear ball bearings.
  • For the FT 100 test soil removal after 100 oscillations is monitored.
  • the whiteness of the HAP discs after cleaning, L* (cleaned) is measured using a Minolta Chroma-meter CR200 .
  • the Cleaning is defined as the % FT 100 Removal where
  • the cohesion of a toothpaste is a good measure of the "stand-up" properties of the ribbon when it has been extruded from a toothpaste tube onto a toothbrush. Higher cohesion values indicate firmer toothpaste ribbons, whereas low cohesion numbers are obtained from low viscosity, poorly structured toothpastes, which quickly sag into the bristles of the brush. It is generally required that a dentifrice has a cohesion within the range of 150 - 430g to provide a good quality, extrudable ribbon, which does not sag and is not too firm.
  • the basic principle of the test is to measure the weight in grams required to pull two parallel plates apart, which have a specific layer of toothpaste sandwiched between them.
  • the pu ⁇ ose built equipment consists of:
  • the spring has a calibration scale of zero to 430g in lOg intervals and can be adjusted to zero at the start of the test.
  • a motor driven ratchet which is attached to the bottom plate and can be used to apply a constant, uniform, smooth vertical pull on the bottom plate of 5cm per minute.
  • a lower polished chrome circular plate of 76mm diameter which is attached underneath to a motor driven ratchet.
  • Two short pegs are located on the top of the plate so that the top plate can be positioned on the bottom plate concentrically from the centres.
  • a metal framework which allows the top plate to be situated concentrically above the bottom plate and the bottom plate to be adjusted so that the plate is approximately horizontal (achieved through the use of levelling feet on the base of the equipment).
  • Ignition loss is determined by the loss in weight of a silica when ignited in a furnace at
  • Moisture loss is determined by the loss in weight of a silica and/or aluminosilicate when heated in an oven at 105° C to constant weight.
  • Dentifrice Formulation 1 was used as a base formulation in which particle components A, B, C and D were varied according to the following examples:
  • Sorbosil AC35 was used as the principal amo ⁇ hous silica abrasive, A, and 10% by weight
  • Doucil A24 Zeolite was used as the crystalline aluminosilicate, C, in dentifrice formulation 1, together with 6.5% by weight thickening silica, D having a pH of 6.4.
  • B There were no booster particles, B, in this example.
  • the pH of the mixture comprising abrasive A, zeolite C and thickener D was 8.5.
  • the properties of the cleansing particles used are given in Tables 1 and 2.
  • Sorbosil AC35 14% by weight Sorbosil AC35 was used as the principal amo ⁇ hous silica abrasive, A, and 20% by weight
  • Doucil A24 Zeolite was used as the crystalline aluminosilicate, C, in dentifrice formulation 1, together with 4% by weight thickening silica, D having a pH of 6.4.
  • B There were no booster particles, B, in this example.
  • the pH of the mixture comprising abrasive A, zeolite C and thickener D was 9.0.
  • the properties of the cleansing particles used are given in Tables 1 and 2.
  • the properties of the resultant toothpaste are given in Table 3
  • Sorbosil AC35 14% by weight Sorbosil AC35 was used as the principal amo ⁇ hous silica abrasive, A, and 10% by weight Doucil A24 Zeolite was used as the crystalline aluminosilicate, C, in dentifrice formulation 1, together with 5% by weight thickening silica, D having a pH of 6.4. 4.2% by weight of Sorbosil AC43 silica booster particles, B, was also added to the formulation. The pH of the mixture comprising abrasive A, booster B, zeolite C and thickener D was 8.2. The properties of the cleansing particles used are given in Tables 1 and 2.
  • Doucil A24 Zeolite is a crystalline aluminosilicate available from INEOS Silicas Limited, Warrington, UK.
  • Sorbosil AC35 is a toothpaste abrasive silica (principal amo ⁇ hous silica) available from INEOS Silicas Limited, Warrington, UK.
  • Sorbosil AC43 is a toothpaste cleaning booster silica available from INEOS Silicas Limited, Warrington, UK.

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Abstract

L'invention concerne une composition de dentifrice contenant un système abrasif qui renferme au moins une silice abrasive pouvant être sélectionnée parmi une première silice dotée d'une abrasion dentaire radioactive comprise entre 30 et 150 et une seconde silice dotée d'une abrasion dentaire radioactive comprise entre 100 et 300, un aluminosilicate cristallin à taille de cristallite moyenne inférieure à 0,2 µm, ainsi qu'un excipient acceptable oralement. Le contenu en poids de la première silice est supérieur à celui de la seconde silice et l'abrasion dentaire radioactive de la seconde silice est supérieure à celle de la première silice.
PCT/EP2005/000105 2004-01-09 2005-01-05 Compositions de dentifrice Ceased WO2005067876A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0400447A GB0400447D0 (en) 2004-01-09 2004-01-09 Dentifrice compositions
GB0400447.9 2004-01-09

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WO2005067876A1 true WO2005067876A1 (fr) 2005-07-28

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080193391A1 (en) * 2005-03-21 2008-08-14 Craig Sinclair Newby Alkyl Sulfate Free and Orthophosphate Free Dentifrice Composition Comprising Fluoride Source and a Silica Dental Abrasive
WO2014124904A1 (fr) * 2013-02-14 2014-08-21 Unilever Plc Compositions de soin buccal non aqueuses
US9968802B2 (en) 2005-12-14 2018-05-15 Pq Silicas Uk Limited Silicas
WO2022123263A1 (fr) * 2020-12-11 2022-06-16 Pq Silicas Uk Limited Particules de silice abrasive

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2601840A (en) * 2020-12-11 2022-06-15 Pq Silicas Uk Ltd Abrasive silica particles

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3862307A (en) * 1973-04-09 1975-01-21 Procter & Gamble Dentifrices containing a cationic therapeutic agent and improved silica abrasive
US4187287A (en) * 1977-08-24 1980-02-05 Colgate Palmolive Company Warm two tone flavored dentifrice
GB2082454A (en) * 1980-08-21 1982-03-10 Grace W R & Co Dentifrice composition containing zeolite
US5964937A (en) * 1995-06-30 1999-10-12 Crosfield Limited Amorphous silicas

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3862307A (en) * 1973-04-09 1975-01-21 Procter & Gamble Dentifrices containing a cationic therapeutic agent and improved silica abrasive
US4187287A (en) * 1977-08-24 1980-02-05 Colgate Palmolive Company Warm two tone flavored dentifrice
GB2082454A (en) * 1980-08-21 1982-03-10 Grace W R & Co Dentifrice composition containing zeolite
US5964937A (en) * 1995-06-30 1999-10-12 Crosfield Limited Amorphous silicas

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080193391A1 (en) * 2005-03-21 2008-08-14 Craig Sinclair Newby Alkyl Sulfate Free and Orthophosphate Free Dentifrice Composition Comprising Fluoride Source and a Silica Dental Abrasive
US9554975B2 (en) * 2005-03-21 2017-01-31 Glaxo Group Limited Alkyl sulfate free and orthophosphate free dentifrice composition comprising fluoride source and a silica dental abrasive
US9968802B2 (en) 2005-12-14 2018-05-15 Pq Silicas Uk Limited Silicas
WO2014124904A1 (fr) * 2013-02-14 2014-08-21 Unilever Plc Compositions de soin buccal non aqueuses
CN105163705A (zh) * 2013-02-14 2015-12-16 荷兰联合利华有限公司 非水性口腔护理组合物
EA034533B1 (ru) * 2013-02-14 2020-02-18 Юнилевер Н.В. Неводные композиции для ухода за полостью рта
WO2022123263A1 (fr) * 2020-12-11 2022-06-16 Pq Silicas Uk Limited Particules de silice abrasive
US20240099947A1 (en) * 2020-12-11 2024-03-28 Pq Silicas Uk Limited Abrasive Silica Particles

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