MXPA01006749A - High water content dentifrice composition and method of making the same - Google Patents

Abstract

A high water content dentifrice composition having a viscosity greater than about 200,000 centipoise (cP) comprising a water content greater than about 50%by weight, abrasive material, binder, and a polyol humectant. This invention provides a high water content dentifrice composition that has acceptable stability, mouthfeel and rheological properties. The inventive dentifrice composition also is relatively inexpensive to manufacture

Description

DENTÍFRICA COMPOSITION WITH HIGH CONTENT OF WATER AND METHOD TO MANUFACTURE IT TECHNICAL FIELD This invention relates to a dentifrice composition with high water content and, more particularly, to a dentifrice composition having a water content greater than 50 weight percent and a viscosity greater than 200,000 centipoise (cP). The invention also relates to a method for manufacturing this dentifrice composition. BACKGROUND ART Toothpaste compositions generally contain combinations of an abrasive material with one or typically several of a thickening system, a wetting system, a flavoring agent and a foaming agent. Other ingredients commonly found in tooth compositions such as toothpaste formulations include detergents or surfactants, colorants or bleaching agents, preservatives, antibacterial agents and fluorides. The use of silicon dioxide as an abrasive component in toothpaste formulations has dramatically changed the technology in the last 20 years when fluoride was established as an active anti-caries ingredient for the prevention of tooth decay. Unlike calcium carbonate, dental grade silicon dioxide proved to be compatible with most fluoride sources. Its predominant use in dentifrices in industrialized countries has contributed to a significant decline in tooth decay and tooth decay among school-age children. The World Health Organization has as its main priority the elimination of dental caries. The Division of Oral Health of Noncommunicable Diseases, of the World Health Organization, published in 1998 a report entitled "School-based Primary Preventive Program for Children" (Primary Preventive Program based on the School for Children). One goal of the project described in this report is to encourage companies to produce "inexpensive, fluoride-containing toothpaste." Although the beneficial impact of the use of a dentifrice containing fluoride in oral hygiene and dental health is well documented, these compositions are relatively expensive for many consumers and, therefore, can not be purchased in many developing countries. The cost of a given toothpaste formulation is often determined by the amount of water that can be incorporated into it. Given the participating economies, the toothpaste formulation would ideally contain as much as a fraction of water as possible without sacrificing the necessary performance and aesthetics. However, the notion of significantly increasing the water content of a toothpaste itself raises concerns about undermining, for example, the stability and uniformity of the toothpaste formulation, its ability to retain its body and shape without experiencing messy bag formation. when it is extruded on the bristles of the toothbrush in order to settle sufficiently on the bristles, or the tendency of the formulation not to leave the dispenser easily when it is opened. In practice, increasing only the water content in conventional toothpaste formulations, while keeping everything else the same, has been found to have a detrimental impact on stability, mouthfeel and rheological properties. In any case, the liquid dentifrice compositions have been sold, particularly but not exclusively in Europe, for many years. These compositions may contain relatively high amounts of water, but have lower viscosity and a thinner mouthfeel than typical toothpaste formulations to which many other consumers have grown accustomed and prefer from aesthetic and performance perspectives. Many consumers will not accept a watery toothpaste. On the other hand, although toothpaste needs a body, it should not be lumpy or too sticky. Examples of the measured viscosity values for various commercial liquid dentifrice compositions sampled are given in Table A below. Table A In view of the above, it can be seen that a challenge and need has existed in the field of toothpastes for the development of a liquid dentifrice that can sustain an increased water content without sacrificing the desired performance and aesthetics. SUMMARY OF THE DESCRIPTION The present invention overcomes the shortcomings of the prior art and satisfies the challenges outlined above. This invention provides a dentifrice composition with a high water content having acceptable stability, mouthfeel and rheological properties. The dentifrice composition of the invention is also relatively inexpensive to manufacture, which can be translated into a more accessible product for consumers. To achieve these and other advantages, benefits and improvements, a high water content dentifrice composition having a viscosity of greater than about 200,000 centipoise (cP) according to this invention is provided which comprises a water content greater than about 50%. weight percent, abrasive material, binder, and polyol humectant. In accordance with one embodiment of the present invention, the high water content toothpaste composition having a viscosity greater than 200,000 cP and including water in an amount greater than about 50 weight percent is formulated as a mixture with the same of abrasive material in an amount of about 8 percent to about 18 percent by weight, silicon dioxide thickener in an amount of about 8 percent to about 15 percent by weight, binder in an amount of about 0.5 percent. one hundred to about 1.5 weight percent, and polyol humectant in an amount of about 1 percent to about 20 weight percent. In order to render the "therapeutic" dentifrice compositions of the invention in nature, the dentifrice compositions of the present invention will typically also contain a water-soluble compound containing fluorine and / or other active compounds as long as they have a beneficial effect on the care and hygiene of the oral cavity protecting the teeth against decomposition, reducing the acid solubility of the enamel of the teeth, reducing bacterial plaque, and / or reducing oral bacteria, among other things. For example, fluorine-containing compounds that provide one or more of these properties can be included in an effective, non-toxic amount in the formulation, which generally can vary from about 0.01 to about 1 weight percent of the overall formulation. Other objects, features and advantages will be readily apparent from the following detailed description of the preferred embodiments thereof. BEST MODE FOR CARRYING OUT THE INVENTION In accordance with the above compendium, the present invention is directed towards a dentifrice composition with a high water content having acceptable rheology, mouthfeel and stability. Generally, the dentifrice composition of the invention will include water in an amount of greater than about 50 percent, abrasive material in an amount of about 8 percent to about 18 percent, silicon dioxide thickener in an amount of about 8 percent. one hundred to about 15 percent, binder in an amount of about 0.5 percent to about 1.5 percent, and a polyol humectant in an amount of about 1 percent to about 20 percent by weight. All percentages by weight described and mentioned in this application for the respective components of the dentifrice composition of the invention are based on the total (overall) weight of all the combined ingredients of the dentifrice composition product. The term "dentifrice" as used herein, includes opaque therapeutic paste formulations. In order to be "therapeutic", the toothpaste compositions of the present invention will typically also contain a water-soluble compound containing fluorine and / or other active compounds as long as they have a beneficial effect on the care and hygiene of the oral cavity by protecting the teeth against decomposition (ie. say, anticaries agents), reducing the acid solubility of tooth enamel, reducing plaque, and / or reducing oral bacteria. The fluorine-containing compounds provide one or more of these properties are included in an effective, non-toxic amount in the formulation, which generally ranges from 0.01 to about 1 weight percent of the overall formulation. The term "therapeutic" as used herein to characterize the dentifrice composition, includes therapeutic agents such as sodium fluoride, stannous fluoride, sodium monofluorophosphate, potassium fluoride, stannous potassium fluoride, triclosan, chlorhexidine, sodium fluorostannate. , stannous chlorofluoride, amine fluoride, alone or in combinations thereof, and other comparable anticaries and / or antibacterial agents commonly used in dentifrice compositions that release or dissociate ions containing fluorine in water. The total water content of the present invention is greater than about 50 weight percent, preferably ranges from about 50 weight percent to about 85 weight percent, and more preferably ranges from about 60 weight percent to about 70 weight percent by weight of the overall dentifrice composition. The percentage (%) by weight of water described herein means the total or combined weight of the water present in the composition including not only additions of pure water but also other water sources contributed from additives and adjuvants that are mixed with the global formulation, such as, for example, water present in a humectant formulation such as sorbitol. The high water content results in the ability to manufacture a toothpaste with a relatively low cost that can be sold and marketed in developing countries around the world. The abrasive material is preferably a precipitated amorphous silicon dioxide such as Zeodent® 113. Other preferred amorphous amorphous silicon dioxide abrasives include silicon dioxides Zeodent® 115, Zeodent®623 and Zeodent®124. Zeodent® silicon dioxides are available of JM Huber Corporation of Edison, NJ. The typical properties of these silicon dioxides are listed in Table B below. Table B For the purposes of this application, the properties reported in Table B are determined as follows. Oil absorption, using linseed oil, is determined by the rubbing method. This method is based on a principle of mixing oil with a silicon dioxide by rubbing with a spatula on a smooth surface until a stiff mastic-like paste is formed. By measuring the amount of oil required to have a paste mixture that will curl when extended, one can calculate the absorption value of silicon dioxide oil - the value that represents the volume of oil required per unit weight of silicon dioxide to saturate the sorptive capacity of silicon dioxide. The calculation of the value of the oil absorption was made as follows: Oil absorption = cm3 of oil absorbed X 100 weight of silicon dioxide, grams = cm3 of oil / 100 g of silicon dioxide The particle size is determined using a Leeds and Northrup Microtrac II. A laser beam is projected through a transparent cell containing a stream of mobile particles suspended in a liquid. The rays of light that affect the particles are scattered through angles that are inversely proportional to their sizes. The photodetector array measures the amount of light at various predetermined angles. The electrical signals proportional to the measured light flow values are processed by a microcomputer system to form a multi-channel histogram of the particle size distribution. The surface area is determined by BET nitrogen adsorption methods of Brunaur et al., J. Am. Chem. Soc. , 60, 309 (1938). The pore volume (pore volume of mercury) is determined using an Autopore II 9220 porosimeter (Micromeritics Corporation). This instrument measures the void volume and the pore size distribution of various materials. The mercury is forced into the voids as a function of the pressure and the volume of mercury introduced per gram of sample is calculated at each pressure setting. The total pore volume expressed herein represents the cumulative volume of mercury introduced at vacuum pressures up to 4200 kilograms / cm2. Increases in volume (cm3 / gram) at each pressure setting are plotted against the pore radius corresponding to the pressure setting increments. The peak in the volume entered against the curve of the pore radius corresponds to the mode in the pore size distribution and identifies the pore size most common in the sample. The pore density is determined using 100 grams of product in a graduated cylinder of 450 milliliters and recording the volume occupied. The density packed or covered is determined by weighing 100 grams of the product in a 250 milliliter plastic graduated cylinder with a flat bottom. The cylinder is closed with a rubber plunger, placed in the apparent density machine and run for 15 minutes. The apparent powder density machine is a conventional motor gear reducer that operates a cam at 60 rpm. The cam is cut or designed to raise and lower the cylinder at a distance of 5,715 centimeters every second. The cylinder is held in place by guide fasteners. The volume occupied by the product is recorded after covering it and calculating the packing density in grams / milliliter. It should be noted that not only amorphous precipitated silicon dioxides but also fluoride-compatible abrasive materials could be used as silica gel, aluminum oxide, aluminosilicate, dicalcium phosphate, gis and precipitated calcium bicarbonate, using them alone or in combinations thereof. The purpose of the abrasive material in the dentifrice formulation is to remove stains on the teeth, which typically can not be removed by the bristles of the toothbrush. The abrasive material also provides general cleaning and removal of the plate. In addition to being compatible with fluoride, the abrasive material should have an RDA value of from about 30 to about 150. In infantile toothpaste formulations, the abrasive material preferably has an RDA value of from about 30 to about 50. In adult toothpaste formulations, the abrasive material preferably has a RDA value of from about 50 to about 90. RDA means radioactive abrasion test of dentin. The procedure for determining the RDA follows the method recommended by the American Dental Association (Journal of Dental Research 55 (4) 563, 1976). In the recommended procedure, human teeth are irradiated with a neutron flux and subjected to a standard polishing regime. The radioactive phosphorus 32 removed from the dentin in the roots is used as an index of the abrasion of the tested dentifrice. A reference water paste containing 10 grams of calcium pyrophosphate in 50 milliliters of a 0.5 percent aqueous solution of sodium carboxymethylcellulose is also measured and the RDA of this mixture is arbitrarily taken as 100. The dentifrice with high water content which is to be tested is prepared as a suspension at the same concentration as the pyrophosphate and is subjected to the same brushing regime. The precipitated silicon dioxide to be tested is prepared as a suspension of 6.25 grams in 50 milliliters of a 0.5 percent aqueous solution of sodium carboxymethylcellulose and subjected to the same brushing regime. The preferred silicon dioxide thickener is also an amorphous precipitated silicon dioxide such as Zeodent® 165 silicon dioxide. Other preferred silicon dioxide thickeners are Zeodent® 163 and Zeofree® 153 also available from J.M. Huber Corporation. The typical properties of these silicon dioxides are listed in Table C below. Table C Other conventionally known silicon dioxide thickeners suitable for dentifrice applications could also be used, alone or in combinations thereof. The binder, which can also be determined herein as a "rubber thickener", is preferably selected from the group consisting of natural gums such as xanthan gum, carrageenan, cellulose gum, tragacanth gum, and / or synthetic gums such as alkali metal carboxymethylcellulose (for example, sodium carboxymethylcellulose), hydroxyethylcellulose, polyvinyl pyrrolidone, starch, water soluble carboxyvinyl polymer, and polyacrylic acids or water soluble polyacrylic acid salts, as used alone or in combinations of the same. For example, a convenient binder is a sodium carboxymethyl cellulose (SCMC). Convenient sodium carboxymethyl cellulose having about 0.6 to about 0.8 carboxymethyl groups per anhydroglucose units is available such as the Aqualon product CMC-7MXF. The binder or gum thickener is used to provide cohesion to the composition and is preferably added to the composition in an amount sufficient to obtain a viscosity greater than 200,000 centipoise in the resulting dentifrice composition. More preferably, the gum binder or thickener is added in an amount to obtain a viscosity of between 220,000 to 500,000 centipoise after 6 weeks of aging at room temperature (about 23 ° C). When the abrasive polishing material is released from the binders during tooth brushing activity, the binders are water soluble in the mouth. The binder is used in an amount of from 0.5 to about 1.5 weight percent, and more preferably about 1 weight percent to about 1.5 weight percent, of the dentifrice composition of this invention. The amounts of binder of less than about 0.5 weight percent will not allow sufficient viscosity and paste stability to be imparted by the toothpaste composition to meet the viscosity criterion presented herein, although binder amounts exceeding 1.5 percent by weight. Weight has been found to result in dentifrice compositions that tend to be lumpy and / or too sticky. Another advantageous component of the dentifrice composition of the present invention is a polyol humectant. The polyol humectant is added in an amount sufficient to facilitate and ensure moisture retention by the dentifrice composition in a manner that prevents drying of the dentifrice composition upon exposure to air. The moisturizer also adds sweetness. In the preferred embodiment the polyol humectant is selected from the group consisting of glycerin (glycerol), sorbitol, polyalkylene glycols such as polyethylene glycol and propylene glycol, hydrogenated starch hydrolyzates, xylitol, lactitol, hydrogenated corn syrup, and other edible polyhydric alcohols, used alone or as mixtures thereof. The polyalkylene glycols useful as the humectant generally have a weight average molecular weight ranging from about 200 to 3,700. The polyalkylene glycol should be used in an amount and with a molecular weight consistent with the overall viscosity requirements of the dentifrice formulation of the invention. The polyol humectant can be used alone or in combination with other types of humectants suitable for toothpaste compositions. Other adjuvants, additives, and materials may be added to the dentifrice composition of the present invention such as flavoring agents, foaming agents (e.g., sodium lauryl sulfate), detergents or surfactants, colorants or bleaching agents (e.g. titanium dioxide, FD &C dyes), condoms (for example, sodium benzoate, methylparaben), and other materials typically found in toothpaste compositions. Optional additional adjuvants are typically present in small amounts, if present, at no more than 5 weight percent each. The ingredients of the dentifrice formulation are typically and preferably mixed thoroughly and uniformly. The dentifrice formulation can be conveniently dosed in the form of a strip with a good body and texture, for example, from a collapsible squeezable tube or a manual pump dispenser. The liquid dentifrice formulation of this invention does not hang on the bristles of a toothbrush because of its high viscosity, although the texture of the dentifrice formulation is neither lumpy nor too thick. Exemplary, the non-limiting methods for preparing the high water content toothpaste compositions of the present invention are illustrated in the following examples. EXAMPLE 1 In this and the following examples, the protocol was used to formulate the dentifrice compositions, unless otherwise specifically indicated in the respective examples. A "premix" was made by adding carboxymethylcellulose (CMC) to water by volume in a Heidolph RZR 2051 mixer available from Heidolph Elektro Gmbh & amp;; Co. KG, Germany. The carboxymethylcellulose and the mixed water were mixed in high mixing for about 30 minutes at room temperature. The resulting mixture had no lumps. After that, sorbitol (70 weight percent solids) and molten polyethylene glycol (PEG) were added to the mixer and the resulting mixture was mixed for about 5 minutes. The polyethylene glycol was heated more than room temperature (molten) to facilitate dispersion. After that, fluoride, saccharin, sodium benzoate and titanium dioxide were added and the resulting mixture was mixed for about 15 minutes. The resulting mixture conuted the "premix". The premix was transferred to a vacuum mixer (Stephan UMC-5 available from A. Stephan u. Sohne Gmbh &Co., Germany). Silicon dioxide abrasives (Zeodent®113) and silicon dioxide thickeners (Zeodent® 165) were added to the premix and mixed for 20 minutes under vacuum at 400 rpm. Sodium lauryl sulfate and flavorings were added and the combination was mixed under vacuum for about 5 to 7 minutes at 400 rpm. The resulting toothpaste was removed from the mixer and placed in 50 cm3 pla toothpaste tubes, sealed and stored for teg. The viscosity of the toothpaste was measured with a Brookfield viscometer model number DV II equipped with a Helipath Stand pedestal and Helipath T-E Spindle spindle. The bottom of the toothpaste tube was cut exposing the toothpaste sample. The tube was held with a vertical open end by placing the tube in a small beaker or other convenient container. The viscometer was set at 5 rpm and the viscosity readings were recorded every 10 seconds for one minute for a total of 6 readings. The 6 readings were averaged and reported as the viscosity in the current age of the pulp. The viscosity was typically determined after one, three and six weeks of aging at room temperature. It can also be tested after accelerated aging at 50 ° C for longer periods. To accelerate aging, toothpaste samples are placed at room temperature (approximately 23 ° C) before the viscosity test. Unless otherwise indicated, the viscosity values provided in this application were determined by the aforementioned protocol after aging a sample of dentifrice composition for 6 weeks at room temperature (approximately 23 ° C). The aesthetic properties of the toothpastes (stability, gloss, separation) were measured visually. Approximately a 2.54 cm ribbon of toothpaste was squeezed from a tube onto a piece of ordinary paper for white notes. After waiting 3-5 minutes, the observations of the aesthetic properties were recorded. Stability refers to the shape of the toothpaste lath and is related to the ability of the toothpaste to stay on top of a toothbrush without sinking between the bristles. "Good" stability means that the ribbon retained its shape. The "bad" stability means that the ribbon was crushed, losing its shape. Gloss refers to the surface appearance of toothpaste. Toothpaste that has lost its bright appearance is dry, sometimes indicating very little moisturizer in the formulation. A glossy tooth paste is preferred over a matte finish. The ratings are either "bright" or "matt." The separation refers to the integrity of the toothpaste formulation. The solid and liquid phases of the toothpaste can be separated, usually due to very little binder or thickener. The liquid will be visible around the squeezed strip of the paste if there is separation. Separation scores are "none" (no separation); "light" (small amount of liquid around the strip); and "large" (large phase separation). Table 1 presents two formulations of inexpensive toothpaste in their corresponding viscosity and aesthetic properties. These formulations were prepared according to the procedure described above using the amounts of ingredients listed in Table 1. a: Cekol 2000 SCMC is a carboxymethylcellulose available from Metsa Specialty Chemicals, Nijmegen, The Netherlands b: The total water was calculated as the sum of the deionized water added to the batch in addition to the amount of water contributed by the sorbitol solution. As can be seen from the data in Table 1, Example 1A and IB of the formulations have acceptable viscosity and acceptable aesthetic properties. Example 2 Nine batches of therapeutic opaque toothpaste were prepared according to the process described above in Example 1 using the amounts of ingredients listed in Table 2. These batches all contained more than 63 percent total water. The batches represent two different types of carboxymethyl cellulose gums (CMC), three different silicon dioxide abrasives and two different silicon dioxide thickeners. All batches had acceptable aesthetic properties and viscosity after 6 weeks.

EXAMPLE 3 Four batches of therapeutic opaque toothpaste were prepared according to the process described in Example 1 above using the ingredients and amounts listed in Table 3 below. These lots contained more than 67 percent total batch water and still had acceptable aesthetic attributes and viscosity.

K3 H Cp or p O Cp cp rO Cp O C1 or cp c: CMC-7MXF CMC-9M31XF each was a sodium carboxymethyl cellulose available from cp rO f-1? - > O Cp or Cp Aqualon, a division of Hercules Corp., Wilmington, DE. d: Carbowax 600 was polyethylene glycol available from Union Carbide, Danbury, CT t t t I- »Cp or Cp O Cp t co Viscosity / Acceleration 50 ° C Example 4 Two high water content toothpaste formulations were prepared as described above in Example 1 using the ingredients and amounts thereof listed in Table 4 below. The RDA was measured in this toothpaste formulation. Both pastes had good aesthetic attributes as well as acceptable levels of abrasion.

EXAMPLE 5 Three batches of inexpensive toothpaste with high water content were prepared as described in Example 1 using the ingredients and amounts listed in Table 5 below. All the formulations had good aesthetic properties and good availability of sodium fluoride.

The fluoride availability in the toothpaste was determined with a specific fluoride ion electrode (Orion # 94-09A) connected to an Orion EA940 meter. Specifically, 10 grams of toothpaste was made slurry in 30 milliliters of deionized water then centrifuged at 11,000 rpm for approximately 15 minutes. 10 milliliters of the resulting clear supernatant and 10 milliliters of regulator were placed in a beaker and the fluoride concentration was read directly from the meter which had previously been calibrated using 100 ppm and 1000 ppm F standards. The regulator consisted of 0.2J3 EDTA / 0.2 THAM (2-amino-2- (hydroxymethyl) -1, 3-propanediol) adjusted to pH 8.0 with 5U NaOH. The present invention may be embraced in specific ways without departing from the spirit or essential attributes thereof and in accordance therewith reference should be made to the appended claims rather than to the above specification to indicate the scope of the invention.

Claims (18)

1. A dentifrice composition with high water content comprising: water in an amount greater than about

50 percent by weight; abrasive material in an amount of about 8 percent to about 18 percent by weight, wherein the abrasive material is an amorphous silicon dioxide; silicon dioxide thickener in an amount of about 8 percent to about 15 percent by weight; and binder in an amount of about 0.5 percent to about 1.5 percent by weight; and polyol humectant in an amount of about 1 percent to about 20 percent by weight; and wherein the dentifrice composition has a viscosity greater than about 200,000 cP. The composition of claim 1, wherein the amorphous silicon dioxide abrasive has an RDA value of about 30 to about 150.

3. The composition of claim 1, having a viscosity from about 220,000 to about 500,000 cP.

4. The composition of claim 1, which has a viscosity from about 200,000 to about 500,000 cP.

The composition of claim 1, wherein the polyol humectant is selected from the group consisting of glycerin, sorbitol, polyethylene glycol, polypropylene glycol, hydrogenated starch hydrolysates, xylitol, lactitol, hydrogenated corn syrup, and combinations thereof.

6. The composition of claim 1, wherein the polyol humectant comprises sorbitol.

The composition of claim 1, wherein the polyol humectant comprises polyethylene glycol.

The composition of claim 1, wherein the gum thickener is selected from the group consisting of carboxymethylcellulose, carrageenan, polyacrylic acids, polyacrylic acid salts, alkali metal carboxymethylcellulose, hydroxyethyl carboxymethylcellulose, polyvinyl pyrrolidone, starch, water soluble carboxyvinyl, tragacanth gum, and xanthan gum.

9. The composition of claim 1, further comprising an anti-caries agent in an effective amount.

The composition of claim 1, further comprising a source of water-soluble fluoride selected from the group of sodium fluoride, sodium monofluorophosphate, stannous fluoride, potassium fluoride, stannous potassium fluoride, triclosan, chlorhexidine, sodium fluorostannate. , stannous chlorofluoride, and amine fluoride.

The composition of claim 1, wherein the composition comprises a substantially uniform and substantially complete mixture of water, abrasive material, silicon dioxide thickener, rubber thickener, and polyol humectant.

12. A method for making a high water content dentifrice composition comprising mixing the following components into a substantially uniform mixture thereof containing a viscosity greater than about 200,000 cP, wherein the mixed components comprise: water in an amount greater than approximately

50 weight percent, wherein the abrasive material is an amorphous silicon dioxide; silicon dioxide thickener in an amount of about 8 percent up to 15 percent by weight; binder in an amount of about

0. 5 percent up to 1.5 percent by weight; and polyol humectant in an amount of about 1 percent to about 20 percent by weight. The composition of claim 1, wherein the water is present in an amount ranging from about 50 percent to about 85 percent by weight. The composition of claim 1, wherein the water is present in an amount ranging from about 60 percent to about 70 percent by weight.

15. The composition of claim 1, wherein the amorphous silicon dioxide comprises precipitated amorphous silicon dioxide.

16. The composition of claim 1, wherein the silicon dioxide thickener comprises precipitated amorphous silicon dioxide. The composition of claim 1, wherein the gum thickener comprises alkali metal carboxymethylcellulose, and the polyol humectant comprises sorbitol. The method of claim 1, wherein the gum thickener comprises alkali metal carboxymethylcellulose, the polyol humectant comprises sorbitol, the amorphous silicon dioxide comprises precipitated amorphous silicon dioxide, the silicon dioxide thickener comprises silicon dioxide amorphous precipitate, and water is present in an amount ranging from about 60 percent to about 85 percent by weight.