GB1599690A - Dental cream composition - Google Patents

Description

(54) DENTAL CREAM COMPOSITION (71) We, COLGATE-PALMOLIVE COMPANY, a Corporation organised under the laws of the State of Delaware, United States of America of 300 Park Avenue, New York, New York 10022, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a dental cream composition having a desirable rheological character. In particular it relates to a dental cream composition of smooth texture with little tendency to form grain, particularly upon aging at low temperatures.

Calcium carbonate or chalk has long been used as a dental polishing agent. In earlier times, in spite of its effectiveness in polishing teeth, it had disadvantages in that it tended to make dental cream somewhat slimy in feel. More recently, however, grades of calcium carbonate have come into use which substantially avoid this problem.

Nevertheless, it has been observed that in dental creams containing calcium carbonate, including modern grades of the material, when the cream further contains sodium lauryl sulphate as a surface active agent, and particularly what is known as broad cut" sodium lauryl sulphate, namely sodium lauryl sulphate having a distribution of alkyl chain lengths, from Cl(, to C1, the C12 content being from 40 to 70% by weight, such as 1 - 8% Clo; 40-70% C12; 13 - 30% C14; 5 - 16% C16; and up to 23% C1; grain formation does occur after storage at low temperatures e.g. between -7 and 7"C.

According to the present invention a dental cream composition comprises from 20 to 75% by weight of a calcium carbonate polishing material, from 0.1 to 5% by weight of a surface active material including sodium lauryl sulphate having a broad distribution of alkyl groups from 10 to 18 carbon atoms, the Cl. content being from 40 to 70% by weight, and from 0.2 to 1% by weight of an additive which is an anionic phosphate ester comprising a mixture of monoester of the formula

diester of the formula

wherein M is hydrogen, alkali metal or ammonium, R is an alkyl group of 10 - 20 carbon atoms and n is an integer from 1 to 6.

Calcium carbonate is available in various grades, particularly as precipitated chalk. For example, grades may have an apparent density of 0.47 - 0.61 gms/cc; a flow point of 19 to 25; a moisture loss of 105"C of 1 - 2%; a particle size such that at least 99.7% of the particles are finer than 74 microns (pass through U.S. 200 sieve), the median size is 4 to 9 microns and not more than 90% are less than 18 microns; and the material is composed of calcite and aragonite in a ratio of from 1:9 to 3:1, typically about 1:10, 1:1, or 3:1. Suitable grades are available from John and E. Sturge Ltd., Birmingham, England for instance as Sturcal H (STURCAL is a trade mark) and from Johann Schaefer Kalkwerke, Diez, West Germany as Schaefer AC.

The polishing material preferably constitutes from 40 to 55% of the dental cream and preferably at least about 95% of the polishing material is calcium carbonate. In addition to calcium carbonate the polishing material may optionally contain up to about 5% of its content of additional polishing agent such as dicalcium phosphate (anhydrous or dihydrate), tricalcium phosphate, dimagnesium phosphate, trimagnesium phosphate, insoluble sodium metaphosphate, hydrated alumina or silica.

Sodium lauryl sulphate has long been used in dental cream compositions but it has generally been used as a "narrow cut" material in which at least 90%, even 99%, of the alkyl groups are C12. Dental creams containing calcium carbonate and "narrow cut" sodium lauryl sulphate often do not become grainy, even upon aging at low temperatures. It is when the "broad cut" sodium lauryl sulphate is employed that the problem of grain upon aging at low temperature can be recognized. A particular sodium lauryl sulphate employed in dental creams of the present invention contains about 3% Cl0; 56% Cl2; 21% C14; 9% C16; and 11% C18 alkyl groups and is commerically available in the form of needles as "LZV" from Marchon Division of Albright and Wilson, Whitehaven, England. Further, "broad cut" grades of sodium lauryl sulphate which may be employed are Tensopol ACL 17 from Tensia S.A., Liege, Belgium and Texapon ZHC from Henkel and Cie, Dusseldorf, West Germany (TEXAPON is a trade mark). Such grades of sodium lauryl sulphate include 40 to 70% C12 of their alkyl distribution. More particularly, they typically have an alkyl distribution of 1 to 8% C(, 40 to 70% C12; 13 to 30% C14; 5 to 16% Cl6; and up to 23% C18. The alkyl groups are substantially straight chain (normal).

In addition to "broad cut" sodium lauryl sulphate, the dental cream optionally may include an additional surface active agent. Such agents may include anionic materials, for instance, water-soluble fatty acid monoglyceride monosulphates (e.g. sodium coconut fatty acid monoglyceride monosulphate), alkyl aryl suphonates (e.g. sodium dodecyl benzene sulphonate), fatty acid esters of 1,2-dihydroxy propane sulphonate (e.g. sodium coconut fatty acid ester of 1,2-dihydroxy propane sulphonate. The anionic phosphate esters of the type indicated above which are also effective as additives to reduce grain formation are surface active and may also serve as part of the surface active material.

A nonionic of ampholytic surface active agent may also be present, such agents including nonionic agents such as sorbitan monostearate with approximately 60 moles of ethylene oxide, condensates of ethylene oxide with propylene glycol (available under the trademark "Pluronics") and amphoteric agents such as quaternized imidazole derivatives which are available under the trademark "Miranol" such as Miranol C2M. It is preferred that the total amount of surface active agent does not exceed 5% by weight of the dental cream. The total surface active material content of the dental cream is from 0.1 to 5% by weight. Preferably 1 to 2% by weight of sodium lauryl sulphate is present.

The anionic phosphate esters are mixtures of mono and di-esters of the formulas hereinabove set forth. They are available from MoDo Kemi Aktiebolaget, formerly Berol Aktiebolaget, of Sweden under the trade mark BEROL and may include an anionic triester moiety to, as well as some non-ionic portion. Berol 729 has alkyl chain lengths of 16 to 18 carbon atoms and contains series of 4 ethylene oxide units. Since the acid form of Berol 729 typically provides a completed dental cream with a pH below 6, this material is generally used in neutralized or partially neutralized from in order to assure a pH above 6 to the completed dental cream.

Further anionic phosphate esters which may be used in acid or neutralized forms are Berol 525 which contains alkyl groups of 10 to 18 carbon atoms and series of 5 ethylene oxide units and Berol 513 which contains alkyl groups of 16 to 18 carbon atoms. However, use of Berol 525 may also provide a completed oral preparation with a pH below 6 and it is preferred to use it in neutralized or partially neutralized form. Further Berol aaionic phosphate esters are available as Berol 521, Berol 724 and Berol 733. The weight ratio of monoester to diester may vary, typically from about 1:10 to 10:1 The grain reduction additive is employed in amount of from 0.2 to 1% by weight, preferably 0.2 to 0.5%. When a dental cream containing calcium carbonate and "broad cut" sodium lauryl sulphate but not including the anti-grain additive is prepared, grain formation may be observed after aging for one month at a low temperature, such as -7 to 7"C, typically 4"C.

The dental cream includes as a vehicle for the polishing material, grain reduction additive and other ingredients, liquids and solids proportioned to form an extrudable creamy mass of desirable consistency. In general, liquids in the dental cream will comprise chiefly water, glycerine, sorbitol or propylene glycol, including suitable mixtures thereof. It is advantageous usually to use a mixture of both water and a binder or humectant such as glycerine and/or sorbitol. It is preferred to use glycerine or mixtures of glycerine with sorbitol. The humectant is generally used in an amount between 20 and 25%, and preferably about 22%. The total liquid content will generally be from 20 to 65% by weight of the formulation, with water being in an amount to bring the total of components to 100%.

It is preferred to use also a gelling agent in the dental cream, such as the natural and synthetic gum and gum-like materials, e.g. Irish moss, gum tragacanth, sodium carboxymethylcellulose, polyvinyl pyrrolidone or starch; all being referred to as "gum". The Irish moss and sodium carboxymethylcellulose are compatible particularly and are preferred gelling agents. The gum content is usually in an amount up to 10% and preferably from 0.5 to 5% by weight of the formulation, with gum in an amount from 0.9 to 1.3% being especially preferred.

The total of liquid and gelling agent (gum) form the dental cream vehicle in which the other components are dispersed or dissolved.

Various other materials may be incorporated in the dental creams of this invention.

Examples thereof are colouring or whitening agents, flavours, sweeteners, preservatives, silicones, chlorophyll compounds and ammoniated materials such as urea, diammoniumphosphate and mixtures thereof. These adjuvants are incorporated in the dental creams in amounts which do not substantially adversely affect the properties and characteristics of the particular type of preparation involved.

A fluoride-providing compound may also be present. These compounds may be slightly soluble in water or may be fully water-soluble. They are characterized by their ability to release fluoride ions in water and by substantial freedom from reaction with other consituents of the dental cream. Among these materials are inorganic fluoride salts, such as suitable alkali metal, alkaline earth metal, and heavy metal salts, for example, sodium fluoride, potassium fluoride, ammonium fluoride, a copper fluoride such as cuprous fluoride, zinc fluoride, a tin fluoride such as stannous fluoride or stannous chlorofluroide, barium fluoride, sodium fluorosilicate, ammonium fluorosilicate, sodium fluorozirconate, sodium monofluorophosphate, aluminium mono-and di-fluorophosphate, and fluorinated sodium calcium pyrophosphate. Alkali metal and tin fluorides, such as sodium and stannous fluorides and also sodium monofluorophosphate are preferred.

The following Example illustrates the invention. All amounts and proportions are by weight.

Example The following dental creams were prepared and placed in unlined aluminium tubes: Parts Components A B Glycerine 6.060 6.060 Sodium carboxymethyl cellulose 1.200 1.200 Sodium saccharin 0.200 0.200 Sodium silicate 0.200 0.200 Sorbitol (70%) 16.000 16.000 Berol 513* --- 0.500 Deionized water 23.433 22.933 Calcium carbonate R 42.000 42.000 Sodium lauryl sulphate LZV*** 1.807 1.807 Flavour 1.100 1.100 pH 8.65 8.20 *Berol 513, employed in dentifrice B is a mixture of anionic phosphate monoesters and diesters of the earlier indicated formulas in which the alkyl group contains 16 to 18 carbon atoms. It is a pasty material with a density of about 1.050 / cm3 at 30"C. It is available from MoDo Kemi Aktiebolaget, of Sweden.

**The calcium carbonate employed is Sturcal H chalk, available from John & E. Sturge Ltd., Birmingham, England.

***The sodium lauryl sulphate employed is "LZV" a broad cut needle material available from Marchon Division of Albright and Wilson.

After aging for three months at 40C, dentifrice A has an appearance which can be noticed as somewhat rough and grainy. On the other hand, the presence of Berol 513 in dentifrice B, reduces grain, such that after storage for three months at 4"C, dentifrice B is satisfactory and shiny after storage.

Likewise improvements are observed when the organic phosphate ester is present in dentifrices containing calcium carbonate available as Schaefer AC from and broad cut sodium lauryl sulphate, including "LZV" as well as needles of Tensapol ACL7 available from Tensia, S.A., Leige, Belgium and needles of Texapon ZHC, available from Henkel and Cie., Dusseldorf, West Germany.

A grain problem also exists when the formula contains 40% calcium carbonate, such as Sturcal H, and 2% dicalcium phosphate as polishing materials, and broad cut sodium lauryl sulphate, such as "LZV", which problem is reduced by the presence of the organic phosphate ester.

WHAT WE CLAIM IS: 1. A dental cream composition comprising from 20 to 75% by weight of a calcium carbonate polishing material and from 0.1 to 5% by weight of a surface active material including sodium lauryl sulphate having a broad distribution of alkyl groups from 10 to 18 carbon atoms, the C12 content being from 40 to 70% by weight, and from 0.2 to 1% by weight of an additive which is an anionic phosphate ester comprising a mixture of monoester of the formula

diester of the formula

wherein M is hydrogen, alkali metal or ammonium, R is an alkyl group of 10 to 20 carbon atoms and n is an integer from 1 to 6.

2. A dental cream composition as claimed in Claim 1 wherein the polishing agent is present in amount of from 40 to 55% by weight of the dental cream and at least 95% by weight of the polishing material is calcium carbonate.

3. A dental cream composition as claimed in Claim 1 or Claim 2 wherein the distribution of alkyl groups in the sodium lauryl sulphate is: C111 from 1 to 8% C12 from 40 to 70% C14 from 13 to 30% C16 from 5 to 16% C18 up to 23%; and the said alkyl groups are substantially straight chains.

4. A dental cream composition as claimed in any of Claims 1 to 3 in which the anionic phosphate ester additive is a mixture of a monoester and diester of the formulae set forth in Claim 1 wherein R contains 16 to 18 carbon atoms.

5. A dental cream composition substantially as described in formulation B of the Example.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. as somewhat rough and grainy. On the other hand, the presence of Berol 513 in dentifrice B, reduces grain, such that after storage for three months at 4"C, dentifrice B is satisfactory and shiny after storage. Likewise improvements are observed when the organic phosphate ester is present in dentifrices containing calcium carbonate available as Schaefer AC from and broad cut sodium lauryl sulphate, including "LZV" as well as needles of Tensapol ACL7 available from Tensia, S.A., Leige, Belgium and needles of Texapon ZHC, available from Henkel and Cie., Dusseldorf, West Germany. A grain problem also exists when the formula contains 40% calcium carbonate, such as Sturcal H, and 2% dicalcium phosphate as polishing materials, and broad cut sodium lauryl sulphate, such as "LZV", which problem is reduced by the presence of the organic phosphate ester. WHAT WE CLAIM IS:

1. A dental cream composition comprising from 20 to 75% by weight of a calcium carbonate polishing material and from 0.1 to 5% by weight of a surface active material including sodium lauryl sulphate having a broad distribution of alkyl groups from 10 to 18 carbon atoms, the C12 content being from 40 to 70% by weight, and from 0.2 to 1% by weight of an additive which is an anionic phosphate ester comprising a mixture of monoester of the formula

diester of the formula

wherein M is hydrogen, alkali metal or ammonium, R is an alkyl group of 10 to 20 carbon atoms and n is an integer from 1 to 6.

2. A dental cream composition as claimed in Claim 1 wherein the polishing agent is present in amount of from 40 to 55% by weight of the dental cream and at least 95% by weight of the polishing material is calcium carbonate.

3. A dental cream composition as claimed in Claim 1 or Claim 2 wherein the distribution of alkyl groups in the sodium lauryl sulphate is: C111 from 1 to 8% C12 from 40 to 70% C14 from 13 to 30% C16 from 5 to 16% C18 up to 23%; and the said alkyl groups are substantially straight chains.

4. A dental cream composition as claimed in any of Claims 1 to 3 in which the anionic phosphate ester additive is a mixture of a monoester and diester of the formulae set forth in Claim 1 wherein R contains 16 to 18 carbon atoms.

5. A dental cream composition substantially as described in formulation B of the Example.