CA1145261A

CA1145261A - Oral preparation containing polyoxyethylene derivative of a fatty alcohol

Info

Publication number: CA1145261A
Application number: CA000366823A
Authority: CA
Inventors: Irving R. Schmolka
Original assignee: BASF Wyandotte Corp
Current assignee: BASF Corp
Priority date: 1980-12-15
Filing date: 1980-12-15
Publication date: 1983-04-26

Abstract

ORAL PRODUCT HAVING IMPROVED TASTE
Abstract of the Disclosure Oral products such as mouthwashes and dentifrices are disclosed which utilize a polyoxyethylene derivative of a fatty alcohol having 15 to 22 carbon atoms wherein the poly-oxyethylene chains are responsible for about 50 to about 90 percent of the molecular weight of the surfactant. Un-expectedly, the nonionic surfactants solubilize peppermint oil and other flavorants at ambient temperatures and below so that the mouthwash compositions of the invention remain clear and haze-free. The visually clear dental creams of the invention also maintain their clarity at ambient temperatures and below.
Both mouthwash and dental creams of the invention are free of the usual bitter surfactant taste.

Description

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ORAL PRODUCT HAVING IMPROVED TASTE
. . . _ .
Background of the Invention 1. Field of the Invention . .
This invention relates to oral preparations including mouthwashes and dentifri~es.

2. Description of the Prior Art Tomlinson in U.S. 4r130~636 disclose dental creams and mouthwash compositions free from bitter surfactant taste wherein the surfactant is an alkyl polyglycol ether car-boxylate. A mouthwash having superior taste characteristicsand improved clarity is disclosed by Januszewski in U.S.

3~639~563. The improved clarity is obtained by selecting nonionic surface active agents for their ability to solubilize one or more oily components contained in the mouthwash. Thus, polyoxypropylene-polyoxyethylene block polymers and polyoxy-ethylene derivatives of sorbitan esters are disclosed as useful surfactants which solubilize ce!rtain oily components and ~hus provide improved clarity in the mouthwash~
Pensak et al, in U.S. 3,947,570, also disclose a visually clear, ha~e-free mouthwash free from unpleasan~ ~a~te which includes a nonionic surfactant which is a polyoxy-ethylene derivative of a sorbitan ester. ~hese references neither disclose nor su~gest the applicant's use o a nonionic surfa~tant consisting of the polyoxyethylene derivative of a fatty alcohol having about 15 to about 22 carbon atoms and wherein the ethylene oxide derived component of the surfactant ~:~L45~6~ `
makes up about 50 to about 90 percent by weight of the surfac-tant.
Summary of the Invention An oral product can be prepared which is free of the usual bitter taste associated with most nonionic surfactants and yet has improved clarity at ambient temperatures and below by utilizing a particular nonionic surfactant solubilizing.
agent especially effecti.ve with peppermint flavoring oil.
Thus the present invention provides an aqueous oral product free from unpleasant, bitter surfactant taste which is visually clear comprising about 0.01 to about 5% by weight of flavoring oil and about 0.1 to about 5.0~ by weight of a nonionic surfactant consisting essentially of a polyoxyethylene derivative of a fatty alcohol having about 15 to about 22 car-bon atoms wherein about 50 to about 90~ by weight of said nonionic surfactant is derived from ethylene oxide.
In addition to the advantages of using the polyoxy-ethylene surfactant in the oral products of the invention, as described above, the surfactants of the invention are biode-gradable and thus contribute less to the pollution of the envi-ronment as compared to certain other types of polyoxyalkylene-based nonionic surfactants.
Detailed Description of the Invention In accordance with this invention, it has been found that mouthwash and dentifice compositions can be prepared containing a tasteless polyoxyethylene fatty alcohol reaction product wherein the fatty alcohol contains about 15 to about 22 carbon atoms and wherein the ethylene oxide-derived portion of the surfactant contains abou-t 50 to abou-t 90 percent by weight thereof. The use of said p~lyoxyethylene-fatty alcohol surfactant is particularly suited for use in a mouthwash wherein a water-insoluble flavoring oil such as peppermint oil is required to be solubilized so as to prevent cloudiness and haze formation at ambient temperatures and below.
Surprisingly, it has been ~ound that the surfactants of the invention are tasteless and, therefore~ additional formulation latitude is provided in the preparation of mouth-wash compositions as well as dentifrice compositionsc Thus, visually clear dentifrice compositions can be prepared con-taining a flavoring oil such as peppermint oil which retain clarity at ambient temperatures and below.
With a few exceptions as noted in the discussion of prior art, generally all commercially available surfactants for use in oral products have a bitter taste. Heretofore, the bitter taste has been overcome by the use of a sweetening ingredient such as saccharin. As is well known, when saccharin is the sole sweetening agent, it too leaves a bit~er taste and other sweeteners are often not acceptable because of the reluctance to add caries-inducing carbohydrate-based sweetening agents and because o~ storage stability problems. One object of the invention is the elimination of the problems in a mouthwash composition associated with solubilizing a flavoring oil, particularly peppermint oil, so as to avoid reduced clarity at ambient temperatures and below.
The invention is also directed to visually clear dentifrice compositions. Such compositions, when containing ~45261 ordinarily water-insoluble flavoring oils such as peppermint oil, have reduced clarity where certain prior art nonionic surfactants are utilized in the dentifrice composition~ In both types of oral products, the use of the nonionic surfactant of the invention alleviates problems related to overcoming the ordinarily bitter taste of prior art nonionic surfactants with sweetening agents.
Broadly, the instant invention provides for an oral product which i8 a visually clear dentifrice or a mouthwash having improved clarity at temperatures below ambient temp~ra-tures comprising a nonionic sur~actant as described above.
Generally, said nonioni~ surfactant is utilized in the visually clear dentifrice or the mouthwash of the invention as the sole surfactant component of the composition but it is also useful when blended with other conventional prior art surfactants in a major proportion of the mixture. Generally, about 0.1 to about 5.0 percent, prefera~ly about 1 ]percent to about 3 percent, and most preferably, about 1 to about 2 percent, by weight o the nonionic surfactant of the invention is employed as the sole surfactant in either the visually clear dentifrioe composition or the mouthwash composition of the invention.
The water-insoluble flavoring oils utilized in the oral compositions of the inventiont for instance peppermint oil, require a water solubilizing amoun~ of the non~onic surfactant of the invention in order to effectually render the oral composition visually clear at ambient temperatures and below.
Generally, where peppermint oil is employed in the composition, 52~

the weight ratio of said nonionic surfactant to said pepper-mint oil is greater than 1.5:1. Preferably, the ratio of said surfactant to peppermint oil is about 5:1 and most preferably 1 0 : 1 .
Minor amounts of prior art nonionic suractants can be employed in admixture with the nonionic surfactant of the invention without substantially contributing to reduction in clarity of the composition or resulting in the usual bitter taste associated with conventional prior art nonionic sur-factants. Where mixtures of surfactants are used, generallyabout 10 to 20 percent by weight of conventional prior art nonionic surfactant i5 used with the surfactants of the invention. In addition, anionic and cationic organic surfac-tants can be employed in admixture with the nonionic surfac-tants of the invention.
Suitable anionic and cationic surfactants are water-soluble salts o~ higher fatty acids, monoglycerides of hydrogenated coconut oil fatty acids, higher alkyl æulfates such as sodium lauryl sulfate, alkylaryl su~fonates, such as sodium dodecylbenzene sulfonate, higher alkyl sulfoacetates, higher fatty acid esters of ly2-dihydroxypropane sulfo~ates, olefin sulfonates and the substantially saturated higher aliphatic acylamides of lower aliphatic amino carboxylic compounds such as those having 12 to 16 carbon atomR in the fatty acid or acyl radicals and the like. Examples of useful substantially-saturated higher aliphatic a~ylamides of lower aliphatic amino carboxylic acids are N-lauroyl sarcosine and the sodium, potassium and ethanol-amine salts of N-lauroyl~
N-myristoyl, or N-palmitoyl sarcosine. These should be sub~tantially free from soap or similar higher fatty acid materials which tend to substantially reduce the effectiveness of these compounds. The use of sarcosinate compounds par-ticularly in dentirice compositions is advantageous as is well known in the prior art since these materials exhibit a prolonged and marked effect in the inhibition of acid ~orma-tion in the oral cavity as a consequence of carbohydrate breakdown~
Conventional nonionic surfactants suitable for use in admixture with the nonionic surfactant polyoxyalkylene-fatty alcohol surfactant of the invention include such non ionic surfactant~ as sorbitan monostearate containing about 60 moles of ethylene oxide, condensates of ethylene oxide with propylene oxide, condensates of propylene glycol and ampho-teric agents such as ~uarternized imidazole derivatives.
Additional examples of conventional nonionic surfactants suitable for use in minor amounts in the oral compositions of Z0 the invention are ~ondensates of an alpha-olefin epoxide and a polyhydris alcohol containing 2 to about 10 carbon atoms and 2 to 6 hydroxyl groups with either ethylene oxide or a heteric mixture of ethylene oxide and propylene oxide. Such heteric polymers have a molecular weight in the range of 400 to 1600 and contain 40 to 80 percent by weight of ethylene oxide or a mixture of ethylene oxide and propylene oxide. The ratio of alpha-olefin epoxide to polyhdyric alcohol is in a molar ratio ~6 , 5~

of 1:1 to 1:3~ ~he preparation of such conventional nonionic surfactants is well known in the prior art. Generally, such surfactants are manufactured under conditions of high tem-perature and high pressure. Generally, the nonionic ~ur-factants are present in the proportion of about 0.1 to about 5 percent by weight.
Generally, the flavoring component is present as a denaturant in the non-toxic alcohol component, i.e., ethyl alcohol, utilized in a mouthwash composition. In the visually clear dentifice compositions of the inventi~n, such flavoring component must be added to the dentifrice mixture separately.
The conventional flavoring eomponents are exemplified by the following materials, menthol, anise oil, benzaldehyde, bitter almond oil, camphor, cedar leaf oil, clorothymol, cinnamic aldehyde, cinnamon oil, citronella oil, clove oil, eucalyptol, lavendar oil, menthol, mustard oil, peppermint oil, phenyl salicylate, pine oil, pine needle oil, rosemary oil, sassafras oil, spearmint oil, thyme oil, thymol, and wintergreen oil.
The mouthwash compositions of the invention ~enerally contain about 60 to 95 percent, preferably about ~0 to 80 percent by weight of water an~ from 0 to about 25, pre~erably about 5 to about 20 percent by weight, most preferably about 15 percent by weight of a nontoxic alcohol such as isopropanol or ethanol. In addition to the flavoring component and the nonionic surfactant which is utilized as a solubilizing agent, the mouthwash compositions of the invention generally contain optional effective amounts of antibacterial agents such as quarternary ammonium compounds or the substantially saturated aliphatic acyl amides. Generally, these anti-bacterial agents are utilized in amounts of about O~Oi to about 0.1 percent by weight. The following illustrative antibacterial agents are useful: benzethonium chloride, diisobutylphenoxyethoxyethyldimethylbenzyl ammonium chloride, N-alkyl pyridinium chlorider N-cetyl pyridinium bromide, sodium N-lauroyl sarcosinate.
Additional adjuvants can be added to provide color, flavor, or sweetening effects, as desired. Examples of suitable sweetening agents include sucrose, lactose, maltose, sorbitol, sodium cycl~mate, and saccharine. The coloring agent is typically added in an amount of 0.01 percent to about 0.02 percenty by weight. Citric acid is often utilized as a flavor additive. Ah types of favoring materialq are generally used in amounts of about 0.01 to about 5.0 percent by weight, preferably about 0.05 percent to about 3.0 percent by weight.
Generally, a buffering ingredient is also added to the mouthwash compositions of the invention in order to prevent natural degradation of the flavoring components of the mouthwash. Generally~ the pH of the mouthwash is adjusted to 3.5 to about 7 r preferably from about 5 to about 6. The buffering ingredient such an alkali metal salt of a weak organic acid, for instance, sodium benzoate, sodium citrate, sodium phosphate, and potassium tartrate is generally added in an amount of about 0.1 to about 1.0 percent by weiyht.

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In addition to the waterl nontoxic alcohol, nonionic surfactant and optional antibacterial, flavoring and pH
buffering ingredients, the mouthwash compositions of the invention can optionally contain at lea~t one humectant selected from the group consisting of glycerine, sorbitol, and propylene glycol. Generally, such humectants are utilized in the proportion of about ~ percent to about 12 percent by weight based upon the total weight of the mouthwash composi-tion. Preferably, the humectant is utilized in an amount of a~out 10 to 12 percent by weight.
The mouthwash compositions of the invention are prepared using methods similar to those well known in the art.
Typically, the ingredients are combined in a specified amount in an amount of water su~ficient to bring the total of com-ponents to 100 percent by weight. Preerably, the alcohol-soluble cvmponents are separately premixed in a suitable mixing vessel and subsequently added to the water. Those components having solubility in water are preferably added ~o the water before mixing the alcohol premixture into the wat~r.
In the preparation of the visually clear~ gelled dentifrice compositions of the invention, besides the in-clusion of similar amounts of a flavoring component and a nonionic surfactant component, as described above, such compositions generally contain a humectant and a water-insolu~le dental polishing agent. The humectant material is selected from the group consisting of at least one of ylycerine, sorbitol and propylene glycol and is present generally in an amount up to about 50 percent to about B0 _9_ ~s~

percent of the visually clear dentifrice composition. Prefer-ably, such compositions contain about 60 to 75 percent of humectant. Gelling agents are known in the prior art and can be selected from natural and synthetic gums such as gum tragacanth, methyl cellulose, polyvinyl pyrrolidone, and hydrophilic carboxyvinyl polymers such as tho~e sold under the trademark Carbopol 934. Generally, about 0.5 per~ent to about 5 percent by weight of gelling agent is used. Often, thicken-ing and gelling of the visually clear dentifrice can be accomplished by the addition of about 1 to about 5 percent by weight of a synthetic, finely-divided, pyrogenic silica such as those sold under the trademark CAB-O-SIL M5, SILOID 244, SILOID 266 and AEROSIL D-200. The pro;portion of flavoring oil is generally about 0.01 to about 5.0 percent, perferably about 0.05 to about 3 percent, by weight of the dentifrice composi-tion and the proportion Qf nonionic surfactant is generally about 0.1 to about 5.0 percent by weight of said dentifrice composition. Generally, the proportion of nonionic surfactant o flavoring oil, i.e., peppermint oil, is greater tha~ 1.5:1, preferably at least 5:1 and most preferably about 10:1. The pH of the visually clear dentifrice composition of the inven-tion can be adjusted to a p~ of 3.5 to 7 or to the preferred pH range of about 5 to about 6 utilizing buffering materials as disclosed above and by the use of acids such as citric, acetic~ chloropropionic, malonic, formic, fumaric, methoxy-acetic, and the water-soluble alkali metal salts thereof~
Because the nonionic surfactant utilized in the visually clear ~s~

dentifrice compositions of the invention is free of bitter taste, it is often unnecessary to utili~e sweetening materials~
Thus, greater formulating freedom is obtained and the flavor-ing and sweetening materials utilized are not undesirably changed in their effectiveness over the characteristics of the pure flavoring or sweetening materials.
Since the usual water-insoluble polishing agents of the type commonly employed in prior art dental creams would tend to reduce the visual clarity of the dentifrice, ordinarily rendering the dentifrice opaque, when visually clear denti-frice compositions are required a dental polishing agent is selected from those polishing agents which have refractive indices close to the refractive indices of the remainder of the dentifrice composition. Generally, the polishing agent is utilized in amounts of about 5 to about 50 percent, preferably about 5 to about 15 percent, by weight of the total weight of the visually clear dentifrice. Examples of suitable polishing agents are certain colloidal silicas and silicates, for in~tance, those silicas sold under the trademark SILOID 72 or under the trademark SANTOCEL 100 and certain synthetic alkali metal aluminosilicate complexes such as sodium alumina silicate.
Various other adjuvants are often employed in dentifrice formulations such as coloring agents, preserva-~ives, silicone compoundsJ chlorophyll compounds, ammoniated materials such as urea, diammonium phosphate and mixtures thereof and other conventional components~ These adjuvants are incorporated in the instant visually clear dentifrice compositions in amounts which do not substantially adversely effect the visual clarity of the dentifrice compositions.
Additional optional ingredients include antibacterial agents as recited above.
The following examples more fully describe the oral products o the invention and show the unexpected resul~s obtained by the use of the nonionic surfactants disclosed herein. The examples are intended for the purpose of illus-tration and are not to be construed as limiting in any way.
Unless otherwise indicated, all parts, percentages and propor-tions are by weight and all temperatur~es are in degrees Centigrade.

Example 1 A mouthwash of the invention was prepared by blending peppermint oil into 95 percent aqueous ethyl alcohol.
Glycerine, sodium saccharin, sodium citrate are dissolved in water together with the surfactant of the invention. The alcohol aqueous ~olutions are blended and the mixture is bottled and the appearance noted. A clear solution is obtained which, upon cooling to a temperature of 24C, is either clear or, at most, faintly opalescent. The composition 10 of the mouthwash i8 as follows:
Ingredient Parts by Weight ~5% ethyl alcohol 15.0 oil of peppermint 0u25 water 72.00 sodium saccharin 0.05 sodium citrate 1.7 ~lycerine 10.0 Cls fatty alcohol ethoxylate so as1.0 to ~ontain 60% ethylene oxide residue Examples 2-6 Example 1 is repeated substituting the following nonionic surfactants ~or the surfactant utilized in Example 1.
A fatty alcohol ethoxylate wherein the fatty alcohol is a mixture of alcohols having 16 to 18 ~arbon atoms ethoxy-lated so as to contain 80 percent by weight of the total weight of the nonionic surfactant of the residue of ethylene oxide, -A 16 carbon chain fatty alcohol ethoxylated so as to contain 62 percent ethylene oxide residue, A 1~ carbon chain fatty alcohol ethoxylated so as to contain 78 percent ethylene oxide residue, A 20 carbon chain fatty alcohol ethoxylated so as to cont~in 55 percent ethylene oxide residue, and A 15 carbon chain fatty al~ohol ethoxylated so as to contain 90 percent ethylene oxide residue.
In each mouthwash formulation prepared, a clear solution is obtained which, upon cooling to 2C, either remains clear or, at most, becomes faintly opalescent.
Example 7 The following visually clear dentifrice is prepared:
In~redient Parts by Weight Sorbitol (70%) 75.0 Glycerine 2S.1 Silicated clay 2.0 AEROSIL D-200 5.0 Sodium alumina silicate 16.0 20 Oil of peppermint 1.0 Coloring agent 1.0 Water 20.0 C1s fatty alcohol ethoxyla~e 2.
containing 60 percent by weight ethylene ox ide residue It is noted that the sodium alumina silicate employed in thi~ example is a eomplex having a refractive 5~

index of 1.46, a moisture content of about 6 percent and an average particle size of about 3~ microns.
While this invention has been described with reference to certain specific embod.ments, it will be recog-nized by those skilled in the art that many variations are possible without departing from the scope and spirit of the invention and it will be understood that it is intended to cover all changes and modifications of the invention disclosed herein for the purpose of illustration which do not constitute departures from the spirit and scope of the invention.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are as follows:

An aqueous oral product free from unpleasant, bitter surfactant taste which is visually clear comprising about 0.01 to about 5% by weight of flavoring oil and about 0.1 to about 5.0% by weight of a nonionic surfactant consisting essentially of a polyoxyethylene derivative of a fatty alcohol having about 15 to about 22 carbon atoms wherein about 50 to about 90% by weight of said nonionic surfactant is derived from ethylene oxide.

An oral product according to claim 1 wherein said oral product is an aqueous mouthwash which is stable and haze-free at ambient temperatures additionally com-prising about 60 to about 95% by weight of water and from 0 to about 25% by weight of a non-toxic alcohol.

A mouthwash according to claim 2 wherein said flavoring oil is peppermint oil and said non-toxic alcohol is ethanol or isopropanol which is present in an amount of from about 5 to about 20 percent by weight.

A mouthwash according to claim 3 wherein said peppermint oil is present in an amount from about 0.05 to about 3 percent by weight and the weight ratio of said nonionic surfactant to said peppermint oil is greater than 1.5:1.

A mounthwash according to claim 2 wherein the weight ratio of said surfactant to said peppermint oil is about 10:1.

A mouthwash according to claim 3 further including a humectant selected from the group consisting of glycerine, sorbitol and propylene glycol in an amount up to about 8 to about 12 percent by weight.

A mouthwash according to claim 6 including glycerine in an amount of about 10 percent by weight.

An oral product according to claim 1 wherein said oral product is a visually clear, aqueous dental cream addi-tionally comprising about 5 to about 50 percent by weight of a water-insoluble dental polishing agent in a gelled dental cream vehicle containing a humectant selected from a group consisting of glycerine, sorbitol, and propylene glycol in an amount of about 50 percent by weight to about 80 percent by weight and about 0.5 to 5 percent by weight of a gelling agent.

-A dental cream according to claim 8 additionally containing a silica-based thickening agent in an amount of about 1 percent to about 5 percent by weight and wherein the proportion of nonionic surfactant to flavoring oil is greater than 1.5:1.

A dental cream according to claim 9 wherein said flavoring oil is oil of peppermint and said dental cream addi-tionally contains coloring agents and water.