MXPA96002897A - Oral composition containing anionic surfactants having a reduced adverse reaction to tissue or irritation - Google Patents

Abstract

The present invention relates to an oral composition containing a surfactant system comprising an effective amount of an anionic surfactant and an alkyl glucoside having the formula RO (C 6 H 10 O 5) x H, wherein R is an aliphatic residue of a C 12 to C 22 fatty alcohol and x is an integer from 1 to 20, and it reduces tissue irritation or

Description

? QMPQglCIQIT QRftE : 1. Field of the Invention This invention generally relates to an oral composition containing an anionic surfactant which exhibits a reduced adverse reaction to oral tissue. 2. v? Preio Surfactants, and particularly anionic surfactants such as sodium lauryl sulfate, are an essential ingredient of the oral compositions and serve as a solubilizing, dispersing, emulsifying and promoting agent for the other ingredients present in the tooth and especially effective in solubilizing the taste. I presented. The cosmetic effect of the presence of the surfactant is that of which it promotes the foam of the oral composition. Oral compositions with a strong foaming ability are preferred by consumers since the foam provides the perception that the oral composition effectively cleans only if it makes good foam.

The incorporation of anionic surfactants such as sodium lauryl sulfate in oral compositions such as dentifrices is known to cause adverse reactions in oral tissue, such adverse reactions having been reported by R.C. Caldwell and R.E. Stallard in the book "Textbook of Preventive Dentistry" 196, W.B Saunders (1977); L.J. Guarnieri, IADR, Extract No. 661 (1974); L.J. Guarnieri, Thesis, University of Idiana (1970). An example of such an adverse reaction is gingival irritation.

The art has therefore sought ways to reduce the adverse reaction to oral tissue caused by oral compositions containing an anionic surfactant such as sodium lauryl sulfate.

Summary of the Invention It has been unexpectedly discovered that oral compositions such as dentifrices, mouth rinses, gels and the like containing anionic surfactants such as sodium lauryl sulfate are less irritating to oral tissue when an effective amount of an alkyl glycoside is incorporated into the oral composition.

In the co-pending patent application of the United States of America number 08/078, 527 describes an oral composition having improved organoleptic properties and rheological storage stability, oral capping contains a surfactant system composed of a mixture of purified sodium lauryl sulfoacetate and an alkyl glycoside. There is no indication in the application that the inclusion of an alkyl glycoside is effective in reducing the irritation of anionic surfactants such as sodium lauryl sulfate.

DESCRIPTION OF THE PREFERRED MODALITIES Suitable examples of the anionic surfactants used in the preparation of the oral compositions of the present invention include water-soluble salts of monoglyceride monosulfates of higher fatty acid, such as the sodium salt of the mono-sulfated monoglyceride of hydrogenated coconut oil fatty acids such as N-methyl N-cocoyl taurate sodium, sodium cocomo-glyceride sulfate, higher alkyl sulfates such as sodium lauryl sulfate, alkyl aryl sulfonates such as sodium sulfonate dodecyl benzene, higher alkyl sulfoacetates such as sodium sulfoacetic lauryl acetate and sodium 1,2-dihydroxy propane sulfonate, sulfolaurate and sarcosinate lauryl sodium higher fatty acid.

The anionic surfactant is incorporated in the oral composition in the present invention at a concentration of from about 0.1 to about 3.0% by weight and preferably from about 0.3 to about 1.5% by weight.

The inclusion of an alkyl glycoside in oral compositions containing anionic surfactants decreases irritation of the anionic surfactant without deleteriously affecting the foaming properties of the oral composition.

The alkyl glycosides which are incorporated in the oral compositions of the present invention have the formula RO (C6H10O5)? H wherein R is an aliphatic residue of a C 12-22 fatty alcohol and x is an integer from 1 to 20 and preferably from 1 to 10 and more preferably from 1.2 to 2.0.

The incorporation of alkyl glycosides in oral compositions is known in the art. For example, U.S. Patent No. 4,748,158 discloses the use of alkyl glycosides in combination with an antimicrobial biguanide compound to improve antimicrobial performance. U.S. Patent No. 4,923,685 discloses an antimicrobial mouthwash containing an antimicrobial biguanide compound, a flavorant and a surfactant system, a combination of C6-Cu alkyl glycoside and the ethoxylated fatty acid glyceride and the partial ester of sorbitan.

Alkyl glycosides used in the practice of the present invention are typically produced by reacting glucose or an oligosaccharide with a fatty alcohol containing 12-22 carbon atoms and more preferably with alcohols containing an alkyl group having from 12 to 18 carbon atoms. carbon atoms. Alkyl glycosides having an alkyl group of 12-16 carbon atoms are preferred in the practice of the present invention. Alkyl glycosides prepared using the fatty alcohols containing less than 12 carbon atoms suffer from the presence of the lower alkyl chain, for example impurities of C 10 free alcohol which deleteriously affect the organoleptic properties of the oral care compositions. within which the alkyl polyglicoside is incorporated. Polyglycosides containing C12-C16 alkyl glycosides are commercially available from Horizon Chemical Division of Hen, Inc. under the trademark "Plantaren".

A preferred Plantaren glycoside especially useful in the practice of the present invention is a non-ionic alkyl polyglycoside sold under the brand name Planteren 1200 UP characterized by the formula: nH2r + lO (° 6H10O5)? H where n = 12-16 and x (degree of polymerization) - 1.4. The product has a pH of 11.4; a specific gravity at 25 * C of 1.1 grams / ml; a calculated lipophilic hydrophilic balance of about 11.5 and a Brookfield viscosity at 35 * C, spindle 21, 5-10 revolutions per minute from about 15,000 to about 20,000 centistokes per second.

The alkyl glycoside is incorporated into the oral care compositions of the present invention at a concentration of from about 0.1 to about 2.0% by weight and preferably from about 0.2 to about 1.0% by weight. In the preparation of a surfactant system according to the present invention, the anionic surfactant and the alkyl glycoside are present in the oral composition at a ratio by weight of anionic to polyglycoside surfactant of 10: 1 to 1: 5, a ratio of weight from 3: 1 to 1: 1 being preferred.

The oral compositions of the present invention can be virtually semi-solid or pasty in character such as a toothpaste, gel or toothpaste. The vehicle of such pasty or semi-solid oral preparations generally contains a polishing material.

Examples of materials useful as polishing agents in the oral composition of the present invention include sodium bicarbonate, water-insoluble siliceous polishing agents, dicalcium phosphate and hydrated alumina, including calcium phosphate dihydrate and calcium dihydrate. dicalcium phosphate and anhydrous dicalcium phosphate. Silicone polishing agents include colloidal silica, xerogel, precipitated silica and sodium aluminosilicates or silica classes containing combined alumina, typically in an amount of about 0.1-7% by weight. Other polishing materials include insoluble metaphosphate, calcium carbonate, trimagnesium phosphate, magnesium carbonate, etc. Mixtures of polishing agents can be used.

Typically, the polishing material is included in the pasty or semisolid dentifrice compositions of the present invention in an amount of from about 15 to about 60% by weight and preferably from about 20 to about 55%.

In a toothpaste, gel or toothpaste, the oral composition is formulated using water and a humectant carrier typically in an amount ranging from about 10 to about 90% of the composition.

Wetting carriers such as sorbitol, typically commercially available in 70% aqueous solution, glycerin, low molecular weight polyethylene glycol, (for example, about 200 to 600) or propylene glycol, exemplify wetting carriers used to formulate toothpaste, gel or compositions. teeth and are incorporated into the oral compositions of the present invention at a concentration of from about 10 to about 40% by weight and preferably from about 5 to about 30% by weight.

The toothpastes, creams and gels typically contain a natural synthetic gelling agent or thickener in concentrations of from about 0.1 to about 10% by weight, preferably from about 0.5 to about 5% by weight. Suitable thickeners include Irish moss, tragacanth gum, starch, hydroxyethyl propyl cellulose, hydrobutyl methyl cellulose, hydropropyl methyl cellulose, hydroethyl cellulose and sodium carboxymethyl cellulose.

Oral compositions of the present invention also include products which are substantially liquid in character such as a mouth rinse or a wash. In such preparation the vehicle is typically a water-alcohol mixture, desirably including a humectant as described below. Generally, the weight ratio of water to alcohol is in the range of from about 1: 1 to about 20: 1, preferably from about 3: 1 to 10: 1 and more preferably from about 4: 1 to about of 6: 1. The total amount of the water-alcohol mixture in this type of preparations is typically in the range of about 70% to about 99.9% by weight of the preparation.

The pH of the other compositions of the present invention is generally in the range of from about 6 to about 8.0. The pH can be controlled with acid (for example citric acid or benzoic acid) or base (for example sodium hydroxide) or buffered (as with sodium citrate, benzoate, carbonate or bicarbonate, disodium hydrogen phosphate, sodium dihydrogen phosphate, etc.). ).

In certain preferred forms of this invention salts that provide fluorine having an effective anticaries can be incorporated into oral compositions and these are characterized by their ability to release fluoride ions in water. Among these materials are the inorganic metal salts, for example, sodium fluoride, potassium fluoride, cuprous fluoride, sodium fluorosilicate, ammonium fluosilicate, sodium monofluorophosphate, mono and aluminum difluorophosphate.

The amount of the fluorinating compound depends to some extent on the type of compound, its solubility, and the type of the oral preparation but must be a non-toxic amount, generally from about 0.01 to about 3.0 in the composition. In a pasty or semi-solid oral composition such as a gel, toothpaste or cream, an amount of such a compound can be used, but it is preferable to employ a sufficient fluoride compound to release about 0.005% to 1% more preferably about 0.1% of the fluoride ion. Typically in the case of alkali metal fluorides, this component is present in an amount of up to about 2.5% by weight, based on the weight of the preparation and preferably in the range of about 0.05% to 1%. In the case of sodium monofluorophosphate the compound may be present in an amount of about 0.1-3.0%.

In a liquid oral preparation such as a mouth rinse or a wash, the fluoride-providing compound is typically present in an amount sufficient to release up to about 1.0%, preferably about 0.001% to 0.5% by weight of fluoride ion. Generally, about 0.01 to about 3.0% by weight of such compound is present.

The pyrophosphate salts having an anticalculus efficacy such as the dialkyl or alkaline tetrametal phosphate salts such as Na4P207, K4P207, Na ^ P ^, Na2H2P207, and Na-J ^ P ^, the long chain phosphates such as sodium hexametaphosphate and Cyclic phosphate such as sodium trimetaphosphate are incorporated into the solid oral compositions of the present invention preferably at a concentration of about 0.5 to about 8.0% by weight. In liquid oral preparations the pyrophosphate salts are incorporated at a concentration of from about 0.1 to about 3% by weight.

LOI Antibacterial agents can also be included in the oral compositions of the present invention. Especially useful are the non-cationic antibacterial agents which are based on the phenolic and bisphenolic compounds, the halogenated diphenyl ether, the halogenated salicylanilides and particularly the fluoros salicylanilides, the esters of benzoate and carbanilides. Examples of such compounds are 4-chlorophenol, 2,2'-trichloro-2-hydroxy-diphenyl ether (Triclosan), 3,4'-trichlorosalicyl anilide, 5-n-octanoyl-3'-trifluoromethyl salicylate, esters of p-hydroxy benzoic acid, especially methyl, ethyl, propyl, butyl and benzyl esters, 3,4,4'-trichlorocarbanilide and 3,3 ', 4-trichlorocarbanilide. Triclosan and 5-n-octanoyl-3'-trichloromethyl salicylanilide in amounts ranging from 0.03% to 1% are preferred for use in the compositions of the present invention. A nonionic antimicrobial agent such as a sesquiterpene alcohol such as a merolidol or bisabolol is also useful in the present invention.

When antibacterial agents are included in the oral compositions of the present invention, an antibacterial enhancing agent may also be included in the oral composition. The use of antibacterial enhancing agents in combination with antibacterial agents such as Triclosan and halogenated salicyl anilide are known in the art, such as for example from U.S. Patent Nos. 5,18, 821 and 5,192,531. Preferably, the antibacterial enhancing agent is a natural synthetic anionic polymeric polycarboxylate having a molecular weight of from about 1,000 to about 1,000,000, preferably from about 30,000 to about 500,000. The synthetic anionic polymeric polycarboxylates are generally used in the form of their free acids or preferably the alkali metal salts, for example potassium and preferably sodium or water-soluble ammonium, partially or more preferably completely neutralized. Preferred are from 1: 4 to 4: 1 copolymers of maleic anhydride or acid with the polymerizable ethylenically unsaturated monomer, preferably the maleic anhydride / methyl vinyl ether having a molecular weight (NW) of from about 30,000 to about 1,000,000, more preferably from around 30,000 to around 500,000. These copolymers are available, for example, as Gantrez, for example AN 139 (M.W. 500,000), AN 119 (M.W. 250,000); and preferably S-97 Pharmaceutical Class (M.W. 70,000), from GAF Corporation.

Polysiloxanes such as liquid silicone oils such as diphenyl or di-polysiloxanes (Ct-C4) and particularly dimethyl-polysiloxane can be used in the practice of the present invention as an antibacterial enhancing agent.

The antibacterial enhancing agent is incorporated in the compositions of the present invention in amounts by weight of from about 0.05 to about 5%, and preferably from about 0.1 to about 35.

Any suitable sweetening or flavoring material can also be employed. Examples of suitable flavor constituents are the flavoring oils, for example, peppermint oil, peppermint oil, pyrella, sassafras, clove, salvia, eucalyptus, cinnamon, lemon and orange, and methyl salicylate. Suitable sweetening agents include sucrose, lactose, maltose, xylitol, sodium cyclamate, perillartin, aspartyl phenyl alanine, methyl ester, saccharin and the like. Suitably the flavoring and sweetening agents can each or together comprise from about 0.1% to 5% more of the preparation.

Agents used to decrease the sensitivity of teeth such as strontium chloride, potassium nitrate and potassium citrate can also be included in the oral compositions of the present invention at concentrations of from about 0.1% to about 10% by weight. weight.

Various other materials may be incorporated into the oral compositions of this invention such as preservatives, such as sodium benzoate, silleones, chlorophyll compounds and / or ammoniated material such as urea, ammonium phosphate and mixtures thereof. These auxiliaries, where they are present, are incorporated in the preparations in amounts which do not adversely affect the desired properties and characteristics.

Teeth whitening agents can also be included in the oral compositions of the present invention. Especially useful are oxidizing agents such as hydrogen peroxide, urea peroxide, peracetic acid, calcium peroxide, sodium perborate, sodium percarbonate or any other source which, in aqueous solutions, acts as a source of hydrogen peroxide. The amount of active oxygen in such oral compositions can vary from 0.7% to 5% by weight and preferably from about 0.5% to about 2% by weight.

The oral composition of the present invention can be prepared by properly mixing the ingredients. In the preparation of the pasty or semi-solid composition such as a toothpaste, a thickener such as carboxymethyl cellulose or hydroxyethyl cellulose is dispersed with a humectant, water, salts, such as tetrasodium pyrophosphate, sodium fluoride, sodium monofluorophosphate, and the sweetener such as saccharin are then added and mixed. A polishing agent such as dicalcium phosphate dihydrate, anionic surfactant, alkyl glycoside and flavor are then added. The ingredients are then mixed under vacuum for about 15-30 minutes. The resulting gel or paste is then piped.

The following examples are illustrative of the present invention but it should be understood that the invention is not limited thereto. All amounts and proportions mentioned here and in the attached clauses are by weight unless otherwise indicated.

Example 1 A series of toothpastes were prepared having the compositions listed in Table 1, in which the surfactant system was composed of a surfactant system containing 1.3% by weight of an anionic surfactant and an alkyl glycoside.

TABLE I COMPOSITION h B C D E INGREDIENT% BY WEIGHT Phosphate calcium dihydrate 48.00 48.00 48.00 48.00 48.00 48.00 48.00 Glycerin 22.22 22.22 22.22 22.22 22.22 22.22 22.22 Anionic glycoside alkyl anhydride C121216 * AG 0.30 0.39 Flavor 0.95 0.95 .95 .95 .95 .95 .95 Sodium monofluorophosphate (MFP) 0.76 0.76 .76 .76 .76 .76 .76 Carboxymethyl Na cellulose (NaCMC) 0.50 0.50 Hydroxyethylcellulose (HEC) 0.50 0.50 Tetra-Sodium pyrophosphate (TSPP) 0.25 0.25 Saccharin Na 0.20 0.20 Deionized water q.s. c.s. c.s. pH 6.6 - 7.2 The anionic surfactant used in each of the compositions mentioned above are listed below: Composition Anionic Surfactant A Sodium lauryl sulfate B Sodium carbonate + Sodium alkyl benzene C Sarcosinate lauryl sodium D Sulfocolaurate E N-methyl N-cocoyl sodium tauride F Cocomonoglyceride sodium sulphate G Sulfoacetate lauryl sodium «Analysis of alkyl glucoside (Plantar 1200 UP): Activity,% 48-52 Free alcohol,% 0.4-0.8 D.P. average 1.4 pH, 10% sun. 11.4 - 11.8 The composition was prepared by mixing the glycerin together with the NaCMC and HEV, then adding TSPP and saccharin Na, followed by the deionized water. The mixture was placed in a double planetary vacuum mixer. The calcium phosphate dihydrate MFP, the flavor, the anionic surfactant and the AG were added to the mixture and the ingredients were mixed under vacuum for about 15-20 minutes. The homogeneous pastes were obtained using the compositions A-F.

The irritation of the combination of the anionic surfactant / alkyl glycoside used to prepare the compositions of the toothpaste AF of the present invention was valued in accordance with the test procedure described in the article entitled "PREDICTING THE IRRITATION OF THE SURFACTANT OF THE RESPONSE OF BLOCKING OF A COLLAGEN FILM "J. Sociedad Cosmética, Chem 37, 199-210 (July / August 1986). In this in vitro test, the swelling, (tritriated water intake of a collagen film substrate correlates with the irritation of the anionic surfactants and the products based on these ingredients.) The swelling response depends on the concentration and swelling of the Higher substrate indicates greater potential irritation The results of this in vitro test have been found to correlate with the findings of clinical and laboratory assessments in vitro and in vivo.

In carrying out the irritation test, the collagen film supplied by Colla-Tec Inc., of Plainsboro, NJ, was prepared from a deep flexor flexor muscle tendon and cut into 1.27 x 1.27 cm squares of approximately 10 milligrams of weight. Each square was placed in a 20 milliliter container and treated with 10 ml of solution containing 1% of a 0.7% mixture of anionic surfactant (AS) in combination with 0.3% alkyl glucoside (AG) Planted 1200 and sufficiently tritiated (^ O) with water to give 1 x 105 dpm / ml.

The film quadrangles were removed from all solutions and each rinsed in one liter of deionized water for about 5 seconds to remove any adhered tritiated water and then placed in a liquid ccintillation vessel.

Films exposed to 1% surfactant solutions were digested in the containers with 1 ml of 2 N NaOH and dissolved in Ecolume (ICN Biomedicals, Inc.) scintillation cocktail with 0.25 ml of concentrated perchloric acid, and analyzed regarding radioactivity using a Beckman LS06800 scintillation spectrometer. The swelling was defined as microliters of tritiated water taken per dry milligram of collagen (ul / mg). The results were recorded in Table II given below.

For comparison purposes, the irritation test was repeated with the exception that the irritation of a surfactant system consisting of only the anionic surfactant at the same concentration as the alkyl glucoside / anionic surfactant system was also determined. The results of these comparative tests are also recorded in Table II given below.

Swelling irritation - collagen (ul / mg) Anionic surfactant (AS)% AS% AS 0.3% AG Sodium lauryl sulfate 23,738 14,633 Sodium alkyl benzene sulfonate 15,197 9,773 Sodium sulfocolaurate lauryl sodium 9.872 7.127 Sulfocolaurate of sarcosinate lauril Sodium 9,685 9,204 N-methyl Sodium 8,872 7,927 N-cocoyl taurate Cocomono-sodium glyceride sulphate 7,785 6,647 Sulfoacetate lauryl Sodium 7,618 7,048 The results recorded in Table II indicate that in each case the anionic surfactant / alkyl glucoside system was substantially less irritating than when the anionic surfactant was present at the same concentration in the test solutions.

Example III To determine the foaming properties of the toothpastes containing the combination of an anionic surfactant and an alkyl glucoside according to the present invention, an artificial saliva solution was prepared following the procedure described in Tavss et al. J. Par Sci. 1984 73 ( g) 1148-52 having the composition shown below.

Composition of Artificial Saliva Concentration ingredients (gp CaClj ^ HjO 0.228 MgCl2.6H20 0.061 NaCl 1.017 ^ COj. ld ^ 0 0.603 NaH2P04.H20 0.204 Na2HP04.7H20 0.273 Water Quantity Suff. Conc HCl Sufficient to achieve pH of 6.9 To artificial saliva were added 16% by weight of dicalcium phosphate dihydrate and 0.3% by weight of flavoring agent together with 0.3% by weight of a surfactant system consisting of an anionic surfactant and alkyl polyglucoside at variable weight ratios, which are shown in Table III. The anionic surfactants were sodium lauryl sulfate (SLS) and sodium dodecyl sulfo acetate (DSS) N-methyl cocoyl taurate (SMCT) and sodium alkyl benzene sulfonate (SABS). The concentrations of the resulting test solution correspond to a 1: 2 dilution of toothpaste in saliva normally associated in the toothpaste in the oral cavity.

In performing the foam test fifteen milliliters of the test solution were transferred to 50 ml of a sterile centrifuge tube. Six replicates were placed in a 37 ° C water bath for approximately 15 minutes. Centrifugal tubes were grasped on a burrel wrist action shaker and agitated an average of 50 times over a period of 10 seconds. The tubes were displaced on 7.0 cms. in each cycle. The upper and lower foam levels were recorded between the tubes between 5 and 20 seconds after the agitation. The differences in the levels provided a value of "Foam Volume in Milliliters". The increase in foam values correlates with the increase in foamability perceived by consumers using toothpaste. A close correlation has been found to exist between the foam test results using diluted toothpaste and the foamability qualified by a human test panel brushed with an undiluted toothpaste. The foam volume of the test solutions is recorded in Table III below.

For the purposes of comparison? the procedure of Example III was repeated except that solutions were prepared in which the anionic surfactant was the only surfactant (0.3% by weight) or the alkyl glycoside (0.3% by weight). These comparative solutions were also tested for foamability. The foam values of these comparative solutions are also recorded in Table III.

TABLE III Foaminess of Toothpaste Foam Volume (mi) Foam Vol. (Mi) AS / AG at a Wt Surfactant Ind.

Surfactant system 1: 3 1: 1 3: 1 10: 1 AS AG SLS / AG 15 21 27 10 7 5 DSS / AG 25 25 27 25 25 5 SMCT / AG 21 22 21 20 20 5 SABS / AG 18 22 22 20 17 5 The data in Table II showed that oral compositions containing the anionic surfactant (AS) / surfactant (AG) glycoside systems exhibited foaming levels equal to or greater than those of either the anionic surfactant or the alkyl glucoside alone.

Claims (12)

R E I V I ND I C A C I O N S

1. An oral composition having reduced irritation with respect to oral tissue, the composition contains a surfactant system comprising an effective amount of an anionic surfactant and an alkyl glycoside having the formula RO (C¿H10Os) HH, wherein R is a aliphatic residue of a fatty alcohol C12 to C22 and x is an integer from 1 to 20.

2. The composition as claimed in clause 1, characterized in that the alkyl glycoside is characterized by R being an aliphatic residue of a C 12 to C 16 fatty alcohol and x is an integer from 1.2 to 2.0.

3. The composition as claimed in clause 2, characterized in that x in the formula is 1.4.

4. The composition as claimed in clause 1, characterized in that the anionic surfactant is sodium lauryl sulfate.

5. The composition as claimed in clause 1, characterized in that the anionic surfactant is sodium alkyl benzene sulfonate.

6. The composition as claimed in clause 1, characterized in that the anionic surfactant is sarcosinate lauryl sodium.

7. The composition as claimed in clause 1, characterized in that the anionic surfactant is suffused laurate.

8. The composition as claimed in clause 1, characterized in that the anionic surfactant is N-methyl-N-cocoyl taurate sodium.

9. The composition as claimed in clause 1, characterized in that the anionic surfactant is sodium cocomonoglyceride sulfate.

10. The composition as claimed in clause 1, characterized in that the anionic surfactant is sulfoacetate lauryl sodium.

11. The composition as claimed in clause 1, characterized in that the anionic surfactant is composed in the oral composition at a concentration of about 0.1% to about 3.0% by weight and the alkyl glycoside is present in the oral composition at a concentration of 0.1% to 2.0%.

12. The composition as claimed in clause 1, characterized in that the weight ratio of the anionic surfactant to the glycoside is from 10: 1 to 1: 5. SUMMARY An oral composition that exhibits reduced irritability to oral tissue is described wherein the composition contains a surfactant system comprising a combination of an anionic surfactant such as sodium lauryl sulfate and C12-C22 alkyl glycoside.