NO852352L - STABLE DENTAL CARE WITH DEXTRANASE. - Google Patents

Description

The present invention relates to new oral preparations with dextranase enzymes which are stabilized enzymatically, physically and cosmetically in the presence of anionic surface-active compounds by the addition of a polycationic stabilizing compound selected from the group consisting of proteins, polypeptides and polyamines which prevent the inactivation of dextranase while maintaining the enzyme activity over time. The presence of the amphoteric surfactant helps to provide mixture stability.

The state of the art is full of information regarding the effectiveness of dextranase against dental plaque, dissolution and removal thereof, as shown in an article by Bowen in the British Dental Journal, vol. 24 number 8, pp. 347-349,

(April 16, 1968); an article by Fitzgerald et al. in JADA,

Vol. 76, pp. 301-304, (February 1968) and an article by Duany et al. in Journal of Preventive Dentistry, vol. 2, No. 2, pp. 23-27, (March - April 1975). The dextranase enzymes also reduce the formation of tooth decay and disease in the root membrane when applied topically. These enzymes cleave and break down the dextrans that are synthesized in the coating from sucrose by Streptomyces mutans. The dextrans serve as an adhesive for attaching the coating.

Consequently, dextranase has been incorporated into common products for oral hygiene such as e.g. toothpastes, rinses and chewing gums containing surface-active cleaning and foaming agents, as shown in the generally available Japanese Patent Publication No. 56834/1973, and in GB Patent Publication No. 1,319,423, which contain an anionic surface-active compound. These surface-active compounds, especially anionic surface-active compounds, act in the direction of deactivating the enzymes such as dextranase, with rapid loss of enzyme activity in the absence of stabilization. It is thus difficult to produce a stable and foaming dentifrice with dextranase. Consequently, a number of stabilizing agents have been incorporated into dental care preparations containing dextranase.

In US patent document no. 3 991 177, e.g. the use of manganese and calcium ions to stabilize dextranase in the dentifrices in the presence of an anionic surfactant such as e.g. sodium N-lauroyl sarcosinate. US Patent No. 3,981,989 describes gelatin or peptone as stabilizing agents for dextranase in the presence of sodium lauryl sulfate. US Patent No. 4,140,758 describes the use of a metal

ion selected from the group consisting of manganese, calcium, magnesium and mixtures thereof as stabilizer/activator for dextranase. According to Japanese patent document No. 013318, 6 February 1980, eugenol and 1-menthol are used as dextranase stabilizers in the presence of anionic surface-active compounds. According to Japanese patent document No. 010350, 27 January 1981, a mixture of dextranase and omega-amino acids is used in oral preparations to prevent the formation of bacterial plaque. French patent application no. 82/05799 describes an oral preparation consisting of a mixture of dextranase and α-1,3-glucanase. According to GB patent application no. 2 061 727A, aluminum oxides and hydrated aluminum oxides are used as abrasives to stabilize the dextranase in the dental care preparation.

US Patent No. 3,562,385 describes preparations

against plaque and calculus containing a mixture of bis-biguanido compound, dextranase and sodium hexametaphosphate.

US Patent No. 3,622,661 describes oral preparations

containing dextranase and the particular binder kruskar-ragen or gum tragacanth to prevent separation after settling. Oral anti-plaque and/or anti-stone preparations containing dextranase are also described in US patent documents no. 3,630,924, 3,686,393 and 3,751,561. Oral preparations containing dextranase in mixture with other enzymes are described in US patent document no. 4,335,101 Dextranase has been modified by molecular modification using a phosphoprotein carrier and a reagent such as ethyl chloroformate to provide longer periods of action in the oral cavity, as described in US Patent No. 4,138,476.

Toothpastes with cosmetic and enzymatic stability containing a neutral protease from B. subtilis stabilized by a partially hydrolyzed protein are described in US Patent No. 4,058,596. The addition of a group IIA metal ion to the mixture of the neutral protease and hydrolyzed protein provides additional stability as described in US Patent No. 4,058,595.

Although the problem of stabilizing dextranase in the presence of anionic surfactants is well known from the past and has been solved by the addition of a number of different stabilizing agents as indicated above, there is no disclosure of the use of a polycationic stabilizing compound selected from the group consisting of proteins , polypeptides and polyamines, which more specifically comprise a quaternized hydrolyzed protein (Crotein Q), polylysine, polyarginine, prbtamine sulfate, ammonium salt of polyacryloxyalkyl, ammonium salt of polyvinylpyridine, polyoxyethylene-(dimethylamino)-ethylene dichloride (Busan-77 and poly-N-(2 -hydroxypropyl methacrylamide).

It has unexpectedly been found that the addition of a polycationic stabilizing compound, comprising proteins, peptides and polyamines, to a dentifrice consisting of a dextranase enzyme and one or more anionic surface-active compounds, preferably in admixture with amphoteric or non-ionic surface-active compounds, provides better shelf-life stability for the enzyme than gelatin and other previously used stabilizing compounds for the enzyme, without adversely affecting the foaming power or the cleansing effect of the anionic surface-active compound.

A primary object of the present invention is therefore to provide a stable dental care agent containing an anionic surface-active compound, a dextranase enzyme and a polycationic and stabilizing compound.

Another object of the present invention is to provide a foaming and stable dextranase-containing dentifrice in the presence of anionic and non-ionic surface-active compounds.

Yet another object of the present invention is

to provide a foaming and stable dextranase-containing dentifrice in the presence of anionic and amphoteric surfactant compounds.

Another object of the present invention is to provide a physically and cosmetically stable dextranase-containing dentifrice with retention of enzyme activity during storage.

Yet another object of the present invention is to provide a stable dextranase-containing dentifrice without adversely affecting the foaming property of the anionic surfactant system.

Further objects, advantages and new features of the invention will be partly indicated in the description below and will partly be understood by those skilled in the art after reviewing the description below or can be understood by practicing the invention. The purposes and advantages of the invention can be realized and achieved by means of the indications and combinations which are particularly highlighted in the claims.

In order to achieve the above-mentioned and other purposes according to the present invention as it is carried out and broadly described, the stable dentifrice according to the invention comprises an anionic surfactant system, a dextranase and a polycationic stabilizing compound selected from the group consisting of proteins, polypeptides and polyamines, in a dental carrier material. Typical stabilizing compounds may be selected from the group consisting of a quaternary derivative of hydrolyzed protein, polylysine, polyarginine, protamine sulfate, ammonium salt of polyacryloxyalkyl, ammonium salt of polyvinylpyridine, polyoxyethylene-(dimethylamino)-ethylene dichloride and poly-N-(2-hydroxypropyl- methacrylamide).

More specifically, the present invention relates to a stable oral preparation which can be in the form of a powder, a paste, a cream, a liquid or a chewing gum, and which comprises an anionic surfactant system, a dextranase in an amount that gives 1,000 to 55,000 units/ grams of initial enzyme activity, and a polycationic stabilizing compound in a weight ratio of 1:1 to 1:2 between anionic surface-active compound and stabilizing compound.

Dextranase enzymes are prepared from a wide variety of sources, all of which are useful in the present invention. Dextranase enzymes are usually produced by growing Penicillium funiculosum or other fungal sources in a medium containing dextran. The dextran is usually of commercial grade obtained from Leuconostoc mesenteroides. This dextran of commercial purity contains approx. 95% α-1,6-glucoside bonds and approx.

5% α-1,3-glucosidic bonds. The Penicillium organism produces the dextranase which partially hydrolyzes the 1,6 bonds.

Dextranase can also be prepared according to methods described in the art. These include the method described by Bowen, "British Dental Journal", vol. 124, No. 6, 16 April 1968, pp. 343-349. Yet another method is described in US Patent No. 2,742,399 (see also Tsuchiya et al, "Journal of Bacteriology", vol. 64, p. 513).

By the method according to Bowen, dextran can be produced from non-cariogenic streptococcus strains such as, for example ATCC 10558, 903-1600, IIA2 + 3 or Leuconostoc mesenteroides and purified according to the method described by Wood et al, "Archives of Oral Biology", vol. 11, 1066, p. 1039 t seq., except that L. mesenteroides is grown at 25°C.

Dextranase can be prepared by inoculating Penicillium funiculosum in flasks containing 250 ml of a medium containing 0.5% yeast extract and 1% dextran. The flasks are incubated at 30°C on a shaking incubator for 4 days. The culture is then centrifuged at 3000 g for 20 minutes and filtered through Whatman 42 filter paper. Dialysis in 16 mm "Visking" tubes against deionized water and concentration 50 times by dialysis against polyethylene glycol (molecular weight 20,000) follows. The dextranase produced according to this method has a molecular weight of approx. 200,000 to 275,000. If desired, the dextranase can be further purified by fractionation with ammonium sulphate.

Additional methods for producing dextranase include that described in US Patent No. 2,742,399.

Dextranases of bacterial origin are also useful

in the present preparations. Dextranase of bacterial origin can be prepared in the usual way where enzymes are derived from bacteria. However, the preferred source of dextranase for the purposes of the present invention is a mutant of Bacillus coagulans, NRRL B-3988 (Beckman dextranase, catalog no. 680000). Dextranase of bacterial origin can be obtained by adding α-1,3-dextran or a mixture of α-1,6-, α-1,3- and α-1,4-dextranes.

The bacterial strain can be inoculated in a shake flask or fermenter for a period of 1 to 5 days at 25 to 40°C. The sterile growth media can consist of the previously mentioned dextran or mutan combined with a mixture of carbohydrate (starch, glucose, sucrose, cellulose), nitrogen-containing compounds (degraded protein, gelatin, casein, ammonium salts), growth stimulators, (yeast extract, corn molasses, "distiller's solubles") or minerals. Preservatives can be added and the enzyme decanted, filtered or centrifuged to precipitate the cells (intracellular dextranase). The extracellular dextranase can be eluted with ammonium sulfate, acetone, sodium sulfate or a similar salt. The intracellular dextranases are autolysed and extracted. After the salt fractionation step, the enzyme can be further purified using several different column chromatography methods (DEAE, Sephadex ® , ECTEOLA, hydroxyapatite) and frozen, or stabilized using the addition of protein, dextran,

salt, etc. (The purification steps are usually carried out at refrigerator temperatures).

The amount of dextranase used in the oral preparations according to the invention is at least such an amount that effectively provides oral hygiene. This amount depends on the dextranase activity, which can usually vary from 1,000 to 55,000 units/gram, and therefore on the way it is prepared.

A typical prepared material of dextranase enzyme has an activity of approx. 5000 to 10,000/gram. A Beckman dextranase unit is the amount of enzyme that gives 1 mol of reducing sugar from 1 .ug of maltose monohydrate or natural dextran per minute at 35°C and pH 6.0.

While smaller amounts of dextranase can be used, dextranase with an activity of approx. 1,000 to 55,000 units/gram be present in amounts from approx. 0.05 to 4% by weight of the oral preparation.

The dentifrice according to the invention preferably contains 5,000 to 55,000 units of initial enzyme activity per

gram of toothpaste, and exhibits physical and cosmetic stability and retention of enzyme activity over time (at least 75% enzyme activity after 12 weeks of aging at 37°C.

An essential ingredient in the present dextranase-containing dentifrice is a compatible anionic surface-active compound to produce a stable coat and help achieve thorough and complete dispersion of the preparation in the oral cavity. The anionic surfactants contain a sulfonate, sulfate, carboxylate or phosphate as the anionic water solubilizing group. Examples of suitable anionic detergents include the soaps, such as the water-soluble salts of higher fatty acids or resin acids, e.g. those which can be derived from fats, oils and waxes of animal, vegetable or marine origin, e.g. the sodium soaps of tallow, grease, coconut oil, tall oil and mixtures thereof, and the sulphated and sulphonated synthetic detergents, especially those with approx. 8 to 26, and preferably approx. 12 to 22, carbon atoms in the molecule. Examples of suitable synthetic anionic detergents include the higher alkyl mononuclear aromatic sulphonates such as the higher alkylbenzene sulphonates containing from 8 to 16 carbon atoms in the alkyl group in a straight or branched chain, e.g. the sodium salts of decyl-, undecyl-, dodecyl-(lauryl)-, tridecyl-, tetradecyl-, pentadecyl- or hexadecylbenzenesulfonate and Cg-C-^g alkyltoluene, -xylene and -phenolsulfonates, Cg-C-^ alkylnaphthalene sulfonate, ammonium diamylnaphthalene sulfonate and sodium dinonylnaphthalene sulfonate, sulfated aliphatic alcohols such as sodium lauryl and hexadecyl sulfates, triethanolamine lauryl sulfate and sodium oleyl sulfate; sulfated alcohol ethers, such as e.g. lauryl, tridecyl or tetradecyl sulfates with 1-5 ethylene oxide residues; ammonium lauryl ether sulfate; sulphated and sulphonated fatty oils, acids or esters, such as the sodium salts of sulfonated castor oil and sulfated castor oil; sulfated hydroxyamides such as sulfated hydroxyethyllauramide; sodium salt of lauryl sulfoacetate; sodium salt of dioctylsulfosuccinate, the sodium salt of oleylmethyl tauride and sodium N-lauryl sarcosinate.

Also included within the scope of the invention are the sulfuric acid esters of polyhydric alcohols which are incompletely esterified with higher fatty acids, e.g. coconut oil monoglyceride monosulphate, tallow diglyceride monosulphate and dihyuroxy-sulfonated higher fatty acid esters such as the higher fatty acid esters of low molecular weight alkylol sulphonic acids, e.g. oil-

acid ester of isethionic acid.

The most commonly used anionic surface-active compounds are ammonium, mono-, di- and triethanolamine, and the alkali metal salts (sodium and potassium) of the higher alkylbenzene sulfonates, the higher alkyl sulfates, the higher fatty acid monoglyceride sulfates, and the sulfated ethoxylated alcohols, ammonium lauryl ether sulfate , sodium N-lauroyl sarcosinate, dioctyl sodium sulfosuccinate and mixtures thereof.

It is preferred to use the anionic compound(s) in an amount of approx. 0.1 to 5% by weight of the carrier or dental fluid.

Other suitable surfactants include non-ionic agents such as condensates of sorbitan monostearate and about 20 to 60 moles of ethylene oxide, condensates of ethylene oxide and propylene oxide condensates of propylene glycol (Pluronics ® ); condensates of higher fatty alcohols or ethers and ethylene oxide, condensates of alkylthiophenols and 10 to 15 ethylene oxide units, and ethylene oxide additions to monoesters of six-valent alcohols and inner esters thereof such as e.g. sorbitan monolaurate, sorbitol monooleate, mannitan monopalmitate and sorbitan monoisostearate. Specific examples include polyoxyethylene-2-sorbitan monooleate ("Tween 80"), polyoxyethylene-20-sorbitan monoisostearate. Weight ratios between anionic and nonionic surfactant of 1:1, 1:2 and 2:1 have been found to give good dextranase stability in the presence of a polycationic stabilizing agent such as e.g. Protein Q.

The amphoteric surfactant, which is a preferred additional surfactant, has both anionic and cationic groups, has ionic equilibrium and its isoelectric point lies at a pH of about 7, and it includes the betaines and sulfobetaines. The betaines are a class of amphoteric surface-active compounds that include alkylbetaines, alkylamidobetaines and alkylaminobetaines with the general formula:

where R is an alkyl group with 10 to approx. 20 carbon atoms, preferably 12 to 16 carbon atoms or the amido radical: or an amino radical:

where R is an alkyl group with approx. 10 to 20 carbon atoms and a is an integer from 1 to 3, R2 and R^ are alkyl groups with 1 to 3 carbon atoms and preferably 1 carbon atom, R^ is an alkylene or hydroxyalkylene group with from 1 to 4 carbon atoms and optionally a hydroxyl group. Characteristic alkyl dimethyl betaines include decyl betaine or 2-(N-decyl-N,N-dimethylamino)-acetate, coco betaine or 2-(N-coco-N,N-dimethylamino)-acetate myristyl betaine, palmityl betaine, lauryl betaine, cetyl betaine, stearyl betaine, etc. The amidobetaines likewise include coconut amidoethyl betaine, coconut amidopropyl betaine, lauramidopropyl betaine and the like.

The sulfobetaines, which are structurally similar to the betaines, have sulfonate groups instead of the carboxylate groups as shown by the general formula:

where R^, R^, R^°g R4 have the same meanings as above,

and includes alkylsulfobetaines, alkylamidosulfobetaines and alkylaminosulfobetaines.

A molar ratio of anionic to amphoteric surfactant of 1:0.8 to 0.8:2, the optimum ratio being about 1.2:1, provides good dextranase stability in the presence of a polycationic stabilizing agent such as e.g. Crotein Q. It is believed that the desirability of this molar ratio is due to the optimal establishment of a mixed micelle system which helps to moderate the denaturing action of the sodium lauryl sulfate. By increasing the betaine content to an amount that gives a ratio between SLS and betaine of 1:2 or more, a stable dentifrice with unsatisfactory taste characteristics is obtained. This surface-active system produces a stable foam and helps to achieve thorough and complete dispersion of the preparation in the oral cavity. J: Garcia Dominguez, International Journal of Cosmetic Science,

Vol. 2, pp. 57-68 (1981) describes that amphoteric betaine prevents the sodium lauryl sulfate from denaturing dextranase in aqueous solution by the formation of mixed micelles by ionic reaction with SLS. However, its use in a dentifrice along with the cationic stabilizing protein provides unexpected and unusual compositional stability and maintenance of enzyme activity after aging.

It is preferred to use the amphoteric and surfactant in an amount of approx. 2 to 6% by weight of the carrier or dental fluid.

The inactivation of the dextranase due to the presence of an anionic surface-active compound in the dental care agent makes it important to add approx. 0.55% by weight of a cationic stabilizing compound with multiple positive charges to react with the anionic surfactant sodium lauryl sulfate (SLS) and thereby reduce its ability to react with the enzyme dextranase. Suitable stabilizers are polycationic and include proteins, polypeptides and polyamines. More specifically, the polycationic stabilizer is selected from the group consisting of a quaternary derivative of hydrolyzed collagen protein, polylysine, polyarginine, protamine sulfate, ammonium salt of polyacryloxyalkyl, ammonium salt of polyvinylpyridine, polyoxyethylene-(dimethylamino)-ethylene dichloride (Busan-7 poly-N-(2- hydroxypropyl methacrylamide). Cationic surfactants do not act as a stabilizer for the dextranase. The ratio of stabilizer:anionic surfactant is preferably within the weight range of 1:1 to 2:1 to bind the anionic surfactant and prevent its reaction with dextranase, respectively.

The quaternary derivative of hydrolyzed collagen product, a preferred polycationic stabilizer, is a product of Croda Inc., New York, known as Crotein Q with a minimum pH of 9.5 to 10.5, is an off-white free-flowing powder and is called steartrimonium hydrolyzed animal protein. The free amino groups in the protein molecule react with the quaternary ammonium reactant so that the quaternized derivative, which has more positive charges, is formed. At pH values below 5.5, Crotein Q will exhibit a double positive charge due to the protonation of NaH groups in the protein chain, as shown schematically on page 2 of Circular No. 7778 from Crodata.

The quaternary group in Crotein Q is still positively charged at pH 9.5.

Crotein Q was evaluated as a stabilizer for dextranase activity in a mixed surfactant system. An aqueous system was used as aging periods are shorter than those required for dentifrices. The effects of temperature, surfactant and concentrations of Crotein Q were evaluated. The time needed for 50% loss of activity (t%) was calculated and used for comparison. Representative data from each survey is reproduced.

Effect of SLS concentration on enzyme activity:

Inactivation of enzyme increased with SLS concentration.

Effect of temperature on enzyme activation:

The enzyme activity is stabilized at lower temperatures.

Stability of enzyme activity as a function of Crotein Q:

In the presence of detergent(s), enzyme stability increases with the concentration of Crotein Q.

Stability studies carried out on dextranase enzymes have shown that the enzyme-activating effects of anionic surface-active compounds such as e.g. sodium lauryl sulfate (SLS), can be reduced in the presence of a polycationic stabilizer such as e.g. Crotein Q. Although the exact mechanism by which the stabilizer affects this function is not known, it is believed that the polycationic stabilizer preferentially prevents the reaction between the enzyme and the anionic surfactant compounds without impairing the foaming property of the surfactant compound. The favored reaction between the stabilizer and the surfactant prevents the inactivation of the dextranase by the anionic surfactant.

The stability of the dextranase-containing dentifrice is measured by the retention of enzyme activity over a long period of time as shown in Table I where comparative samples of the dentifrice containing anionic and/or non-ionic surface-active compounds and stabilizers are evaluated using the following procedure. To 0.05 ml of diluted dextranase in distilled water containing 200 to 300 units/ml is added 0.95 ml of dextran (average molecular weight 110,000) dissolved in 0.1 M sodium acetate, and the dextran is digested for 30 minutes at 37°C. At the end of the cleavage period, 1 ml of color reagent is added with stirring and heated in a boiling water bath for 15 minutes. The samples are cooled and 10 mL of water is added with stirring, and OD readings are taken at 549 nM using the maltose standard. 1.0 ml of maltose

(100 - 1000 ug/ml) and 1 ml of color reagent is boiled for 15 minutes, cooled and O.D. is read at 540 nM after addition of 10 ml

I^O. The color reagent consists of 5 g of 3,5-dinitrosalicylic acid,

1 g of phenol, 0.25 g of sodium sulphite and 10 g of sodium potassium tartrate dissolved in 500 ml of 2% NaOH. A unit of dextranase activity is defined as the release of 1 ug of maltose monohydrate (Baker) per minute at 37°C.

Examples 1 - 7 are set out more fully below.

Footnotes to Table I:

x

Control toothpaste containing enzyme but no SLS or stabilizer

Block polymer with approx. 80% polyoxyethylene and approx. 20% polyoxypropylene, the latter radical having a molecular weight of 3,250, obtained from BASF Wyandotte Co.

<XXX>Water soluble polymer compound, a high molecular weight polyethylene oxide polymer obtained from Union Carbide Corporation.

The table shows that the enzyme per se in the absence of detergent is unstable in toothpaste. Addition of SLS increases deactivation rate (1). Addition of Pluronic w to the SLS/ enzyme dentifrice (3) does not stabilize the dextranase. Further addition of Polyox (w 5) provides sufficient stabilization (4) compared to Crotein Q, (5) provided better enzyme stability in the dentifrice than gelatin (compare 5 with 6). Polyvinylpyrrolidone (7) is not effective when it comes to stabilizing dextranase in the dentifrice.

The stability of the dextranase-containing dentifrice as measured by the retention of enzyme activity over a long period of time is also shown in Table II where comparative samples of the dentifrice containing anionic and amphoteric surfactant compounds have been evaluated using the manual method of Tsuchiya et al, Journal of Bacteriology, vol. 64 (4) pp. 513-514 (1952), which can be modified for the Technicon autoanalyzer, in both cases using the colorimetric reagent dinitrosalicylic acid. Stored samples solubilized in water and buffer were incubated for 11.5 minutes with dextran substrate, the reaction was stopped by boiling, the solution reacted with color reagent, and the degree of absorbance read and compared to a glucose standard curve to determine percent residual enzyme activity. Despite discrepancies between enzyme activities detected in stored dentifrice samples that showed increasing activity with age, trends provided evidence of a gradual loss of enzyme activity in the dentifrice at the end of 12 weeks of storage at 37°C. In some of the better preparations, spot tests were carried out and verified by manual analysis a loss of up to 30% after 12 weeks using the method described above.

Examples 8 - 10 are set out more fully below.

Examples 11 - 17 show other dental care preparations with

two surface-active compounds where conventional humectants, thickeners, flavoring agents and the like are used in the usual amounts indicated in the description.

Table 1 continued

Calculations:

SLS (94% active, molecular weight 288.38) 18 g x 0.94 = 16.9 g = 0.0587 mol.

Betaine (27% active, molecular weight 283) 50 g x 0.27 = 13.5 g = 0.0477 mol.

Molar ratio SLS:Betain = 0.06:0.05 = 1.2:1.

The reactions between the stabilizer and the anionic surfactant to prevent the reaction of the latter with dextranase do not completely reduce the foaming ability of the anionic agent. The foaming properties of the surfactant compounds were measured in accordance with the standard procedure for measuring foam height. This analysis was carried out at 37°C both in distilled and in hard water (105 ppm CaCl2 and 70 ppm MgCl2). Solutions containing 0.1% SLS and 0.2% Crotein Q alone or in a mixture were prepared. Foam volume was measured in ml after 30 revolutions of the measuring cylinder.

These data show that Crotein Q, being non-foaming, does not readily reduce SLS foaming in distilled water, and increases SLS foaming in hard water. It is also noticed that foaming with the help of SLS is greatly reduced in hard water, but is greatly increased with the help of the stabilizer Crotein Q.

The curve below shows the relative foam volumes in distilled water and hard water.

These data show that SLS produces the largest foam volume in distilled water. , The mixtures containing SLS and protein foamed better than the mixture of SLS and betaine, Crotein and betaine, and betaine alone. It is also noted that protein does not readily reduce SLS foaming although betaine does. In hard water, SLS foaming is greatly reduced, while betaine foaming is unchanged. In hard water, SLS foaming is greatly increased with the help of the stabilizer Crotein. Above all, these results show that the system that provides optimal enzyme stabilization, SLS + Crotein + betaine, exhibits good foaming characteristics regardless of the water's hardness. This point is important as the concentration of divalent cation in the oral cavity is very high.

Investigations with accelerated aging further show that enzymatically, physically and cosmetically stable dentifrices containing approximately 5,000 units of dextranase per g dentifrices, exhibit good foaming in the presence of betaine and anionic surfactants and the cationic stabilizer as shown in Table IV.

Toothpastes and tooth powders usually contain a polishing agent or abrasive which is essentially insoluble in water and which is compatible with the preparation. Preferred compatible materials which do not adversely affect the composition of the dentifrice include dicalcium phosphate dihydrate, silica and hydrated alumina. The polishing agent can be the only carrier material in a tooth powder and is present in an amount of up to approx. 80% of the toothpaste and usually approx. 30-75% of the toothpaste.

In toothpaste preparations, the liquids and solids should necessarily be present in a ratio that gives a creamy mass of the desired consistency that can be extruded from a container under pressure or a compressible tube (e.g. of aluminum or lead). Generally, the liquids in the toothpaste mainly contain water, glycerol, aqueous solution of sorbitol, propylene glycol, polyethylene glycol 400, etc., as well as suitable mixtures thereof. It is usually advantageous to use a mixture of both water and a wetting agent or binder such as e.g. glycerol or sorbitol. The total liquid content will usually be approx. 20-75% of the preparation. The amount of water is usually approx. 10-25% of the preparation. It is also preferred to use a gel-forming agent in toothpastes such as the natural and synthetic rubbers and rubber-like materials such as krus-carrageenan, gum tragacanth, starch, sodium alginates, carboxymethylcellulose, Viscarin GMC, Iota-carrageenan and others, usually in an amount up to approx. 10%, and preferably approx. 0.2-5%, of the carrier or liquid.

The carrier can suitably contain a fluorine-containing compound with a beneficial effect on the care and hygiene of the oral cavity, e.g. reduction of enamel solubility in acid and protection of the teeth against decay. Examples of such compounds include stannous fluoride, potassium stannous fluoride, sodium hexafluorostannate, stannous chlorofluoride, sodium fluorozirconate and sodium monofluorophosphate. These substances which dissociate or release fluorine-containing ions in water may suitably be present in the carrier in an effective but non-toxic amount, usually in the range of about 0.1-5% by weight.

Various other materials can also be incorporated into the carrier. Examples of such are coloring or bleaching agents (e.g. titanium dioxide), preservatives (e.g. sodium benzoate), silicones, chlorophyll compounds, ammonium-containing compounds such as e.g. urea, diammonium phosphate and mixtures thereof, alcohol, menthol and other ingredients. These additives are incorporated into the powder preparations in amounts that do not have any significant adverse effect on the properties and characteristics, and are selected and used in appropriate amounts depending on the specific type of preparations involved.

Flavorings or sweeteners of the type usually used in dental care products are incorporated into the carrier. If such substances are present, they help to modify the specific taste of the flavoring in the desired way. Examples of such additives include flavor oils, e.g. oils of spearmint, peppermint, wintergreen, sassafras, clove, sage, eucalyptus, marjoram, cinnamon, lemon and orange, as well as methyl salicylate. Suitable sweeteners include sucrose, lactose, maltose, sorbitol, sodium cyclamate and saccharin. The flavoring and sweetener can suitably together amount to approx. 0.01 to 2% of the carrier.

The dentifrice can be prepared by mixing the ingredients appropriately. For example, a gel-forming agent such as e.g. sodium alginate, carboxymethylcellulose or Iota-carrageenan and a preservative such as e.g. sodium benzoate, if this is used, in a wetting agent such as glycerol, in the manufacture of a toothpaste. Water may also be present. Additional moisturizer

and water can then be mixed with the dispersion, and a homogeneous paste, gel or cream is formed. Then, tooth grinding agent, surface-active agent and flavoring agent are added. The toothpaste is then thoroughly deaerated (e.g. under vacuum) and filled into tubes. The preparation can be deaerated during mixing or after mixing.

In the examples below, all amounts of various ingredients are based on weight unless otherwise indicated.

Examples 1-7

The stabilization properties of Examples 1-7, which were measured as retention of enzyme activity over a period of time and are set forth in Table I, clearly demonstrate the excellent properties of Example 5 containing a polycationic stabilizer in a dentifrice with dextranase and anionic surfactant compound according to the present invention. The other examples are controls containing no polycationic stabilizer (1), and replacement of the polycationic stabilizer with non-ionic surfactants (3 and 4) or cationic compounds (7) or gelatin (6). The omission of the betaine reduces the enzyme stability of this preparation to zero.

The table below further defines dextranase-containing dental care preparations with physical and cosmetic stability and retention of enzyme activity after storage.

Examples 18-26 comprise an aqueous carrier containing a suitable flavoring agent. Examples 18-21 contain 1.8% dextranase. Example 22 contains 2.1%, Example 23 contains 2.5%, and Examples 24-26 contain 3.6% dextranase. Conventional wetting agents or mixtures thereof were used in appropriate amounts as defined in the specification. Examples 18, 19, 21, 24 and 26 comprise glycerol, while examples 20, 22, 23 and 25 comprise a mixture of glycerol and sorbitol.

Variations can be made in the above preparations. For example, the particular anionic surfactants in the examples can be replaced with other anionic surfactants such as e.g. higher alkylbenzene sulphonates, fatty acid soaps such as tallow soap, sulphated alcohol ethers etc. In the same way, the specific surface-active betaine compounds in the examples can be replaced by other betaines and sulfated betaines. Likewise, the particular nonionic surfactant compounds in the examples can be replaced with other nonionic surfactant compounds.

Other thickeners or gelling agents can replace carboxymethylcellulose, carrageenan or sodium alginate, e.g. starch, mug carrageenan, gum tragacanth etc.

Likewise, Crotein Q, which is used in the examples, can be replaced by other polycationic stabilizers such as e.g. polylysine, polyarginine, protamine sulfate, ammonium salts of polyvinylpyridine, poly-N-(2-hydroxypropylmethacrylamide).

Claims (20)

1. Foaming, stable oral preparation, characterized in that it comprises one or more anionic surface-active compounds, a dextranase in an amount that gives 1000 to 55,000 units/g of starting enzyme activity, and a polycationic stabilizer in an amount sufficient to stabilizing the enzyme against loss of activity during storage, and against inactivation due to the presence of the anionic surface-active compounds, selected from the group consisting of proteins, polypeptides and polyamines, where the weight ratio between anionic surface-active compound and stabilizer is 1:1 to 1:2, in a dental carries. 2. Oral preparation according to claim 1, characterized in that the polycationic stabilizer is selected from the group consisting of a quaternary derivative of hydrolyzed collagen protein, polylysine, polyarginine, protamine sulfate, ammonium salt of polyacryloxyalkyl, ammonium salts of polyvinylpyridine, polyoxyethylene-(dimethyl-amino)-ethylenedichloride , poly-N-(2-hydroxypropylmethacrylamide). 3. Oral preparation according to claim 1, characterized in that it contains a non-ionic surface-active compound in a weight ratio between non-ionic surface-active compound and anionic surface-active compound of 2:1 to 1:2. 4. Oral preparation according to claim 1, characterized in that it contains an amphoteric surface-active compound selected from the group consisting of betaines and sulfobetaines in a molar ratio between anionic surface-active compound and amphoteric surface-active compound of 1:0.8 to 0.8:2. 5. Oral preparation according to claim 4, characterized in that the amphoteric surface-active compound has the general formula: where R, is an alkyl group with 10 to 20 carbon atoms, the amido radical: or the amino radical: where R is an alkyl radical with 10 to 20 carbon atoms and a is an integer from 1 to 3, R2 and R3 are alkyl radicals with 1 to 3 carbon atoms and R^ is an alkylene or hydroxyalkylene group with 1 to 4 carbon atoms, and amounts to approx. 2-6% by weight of the preparation. 6. Oral preparation according to claim 1, characterized in that the polycationic stabilizer constitutes approx. 0.5 to 5% by weight of the preparation. 7. Oral preparation according to claim 1, characterized in that the dextranase constitutes approx. 0.05 to 4% by weight of the preparation. 8. Oral preparation according to claim 1, characterized in that the anionic surfactant compound is sodium lauryl sulfate. 9. Oral preparation according to claim 1, characterized in that the anionic surfactant compounds are sodium lauryl sulfate and ammonium lauryl ether sulfate. Oral preparation according to claim 3, characterized in that the non-ionic surface-active compound is a block polymer of approx. 80% polyoxyethylene and approx. 20% polyoxypropylene with a molecular weight of 3,250. 11. Oral preparation according to claim 1, characterized in that it is available in the form of a toothpaste containing approx. 30-75% by weight of a water-soluble polishing agent. 12. Oral preparation according to claim 1, characterized in that it is available in the form of a tooth powder containing approx. 70-80% water-insoluble polishing agent. 13. Oral preparation according to claim 1, characterized in that it is in the form of an aqueous mouthwash containing approx. 5-10% ethanol. 14. Oral preparation according to claim 1, characterized in that it is in the form of a chewing gum comprising approx. 20-35% of a rubber base containing a natural or synthetic elastomer filler. 15. Oral preparation according to claim 11, characterized in that the polishing agent is hydrated aluminum oxide. 16. Oral preparation according to claim 11, characterized in that the polishing agent is dicalcium phosphate dihydrate. 17. Oral preparation according to claim 11, characterized in that the polishing agent is silicon oxide. 18. Oral preparation according to claim 11, characterized in that it has a liquid content of 20-75% by weight of the preparation. 19. Oral preparation according to claim 4, characterized in that the polycationic stabilizer is a quaternary derivative of hydrolysed collagen protein. 20. Oral preparation according to claim 11, characterized in that the polycationic stabilizer is a quaternary derivative of hydrolysed collagen protein.