CA1039656A - Clear gel dental compositions - Google Patents
Clear gel dental compositionsInfo
- Publication number
- CA1039656A CA1039656A CA230,362A CA230362A CA1039656A CA 1039656 A CA1039656 A CA 1039656A CA 230362 A CA230362 A CA 230362A CA 1039656 A CA1039656 A CA 1039656A
- Authority
- CA
- Canada
- Prior art keywords
- silica
- gel
- weight
- clear gel
- composition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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- Cosmetics (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A clear gel-like dental composition for cleaning the teeth comprising as the active ingredient about 10-15% by weight of a precipitated silica, said silica being produced by the destabilization and precipitation of silica from soluble sodium silicate by the addition of a mineral acid and having a particle size ranging from 100-300 Angstrom units in diameter and having a surface area ranging from 10m2/g to 300m2/g. Such gel compositions, in comparison with known compositions, exhibit a better shelf-like, and an improved compatibility with fluoride ions.
A clear gel-like dental composition for cleaning the teeth comprising as the active ingredient about 10-15% by weight of a precipitated silica, said silica being produced by the destabilization and precipitation of silica from soluble sodium silicate by the addition of a mineral acid and having a particle size ranging from 100-300 Angstrom units in diameter and having a surface area ranging from 10m2/g to 300m2/g. Such gel compositions, in comparison with known compositions, exhibit a better shelf-like, and an improved compatibility with fluoride ions.
Description
~ ( ~
~)396S6 The present invention relates to compositions of matter and, more p~rticularly, the present invention relates to novel den-tal compositions which are characterized as having a clear gel consistency and exhibiting a high degree of cleansing properties. Still more particu-larly, the present invention relates to a clear gel dental composition containing a non-porous form of precipitated silica as the principal cleansing agent.
Heretofore, particulate dehydrated silica gels have been included in dentifrice compositions as an active ingredient to enhance their polishing and cleansing properties. Please see, for example, Canadian patents 835,353, 911,335 and 914,069.
We have found that these dental compositions, while providing good cleansing properties exhibit instability, e.g., loss of gel consistency, upon storage. This instability is more pronounced when therapeutic amounts of a fluoride compound such as, for example, sodium mono fluorophosphate is added to such a composition. These instabilities obviously make the dental compositions commercially less attractive.
We have now found that it is possible to formulate den-tal compositions which not only provide good cleansing and polishing of the teeth but which are also stable over long periods of time. In addition, therapeutic amounts of fluoride can be included without loss of stability.
The silicas used in the aforementloned patents are characterized as "dehydrated silica" or "Xerogel".
In contrast thereto, silicas used herein are prepared in accordance with the procedures described in United States Patents 3,110, -- 606 and 3,582,379 and available under the trade name of "ZEo-49." In Canadian Patent 835,353,-for example, the silica is prepared by treating sodium silicate with a mineral acid. After gelling, the hydrogel is dried and reduced to a small particle.
*Trade Mark , ......
1~39~S6 The precipitated silicas useful for the present invention are pro-duced by the destabilization and precipitation of silica from soluble sodium silicate by the addition of a mineral acid under carefully controlled conditions. The reactants, both silicate and acid, are dilute solutions ~-and the reaction is carried out at an elevated temperature with agitation.
The addition of reactants or the reaction rate is extremely critical as the first phase in the reaction is the development of a hydrosol. The hydrosol ~ -stage is a colloidial dispersion of the silica in a highly polymerized form of micellular development. Under the formation conditions, the micelles are in a metastable state and are the nuclei for the precipitation of the silica particles. The particles occur in discrete spherical particles or in irregularly shaped clusters of the particles called aggregates. The size of the particles and the state of aggregation are controlled by the process ~ -conditions. The particles are then separated by filtration from the aqueous medium in which they were precipitated. The filter cake is washed with water to displace the precipitation medium which contains soluble salts.
The filter cake is then dried by forced hot air and the dry powder is ground to a state suitable for use. The ultimate particles in the dry powder may vary from 100 to 300 A in diameter with surface areas ranging from 10 m /g to 300 m2/g.
The major distinguishing differences between the silica gel or xerogel products disclosed in the aforesaid Canadian patents and the pre-cipitated silicas useful for the present invention are the high concentra-tion of the reactants, the low temperature of the reaction, the fast reaction rate and the absence of agitation during the formation of the hydrogel phase.
The hydrogel phase is characterized by the infinite polymerization of the silica to the state that the liquid phase is completely encapsulated and immobilized within the framework of the solid. The hydrogel is then disin- ~ -tegrated with agitation, and the solid phase is recovered by filtration, 1~396S6 washing and drying. The dried gel is termed a xerogel which is a gel that has been separated from its mother liquor or the gel is simply "silica gel."
Sueh a gel is readily distinguishable from precipitated silicas by its high surface area, which ranges from 300 ~o 1000 m /g. The high surface area is the result of the internal porosity within the ultimate particle.
This internal porosity is due to the interconnecting channels or network formed during the hydrogel stage of the manufacturing process. In the preeipitated silicas, most of the surface area is due to the area of the external surfaee.
In a typieal embodiment of the present invention, about 1 to 20%
and, typieally, 12.5% of the precipitated silica available under the trade name l'ZEO" from J. M. Huber Corporation, Havre de Graee, Maryland, 21078, is blended together with 0.1% of sodium earboxymethyl cellulose and 1% of polyethylene glycol at a temperature of about 90 C. To enhance the wett-ability of such a eomposition, small amounts of a surfaee active agent sueh as sodium lauryl sulfate~ a small amount of a humeetant sueh as glycerine or sorbitol may also be ineluded. Optionally, a small amount of pyrogenic siliea sueh as silica aerogel may also be included as a thickening agent and to broaden the eleansing properties. In order to enhance consumer acceptance, eoloring agents and flavoring agents may also be added.
The ingredients utilized to form the gel base are not critical so long as they are eompatible with the preeipitated siliea to give an optically elear gel. That is to say, instead of sodium earboxy methyl eellulose, other - thiekening agents sueh as carboxy polymer (carbopo~) and other synthetic binders, namely silieone dioxide derivatives sueh as Zeosyl* 200, may be used.
PEG 6000*, for example, may be substituted by other stiffening agents known in the art.
A fluoride compound may be advantageously ineluded to impart anti-earies properties. Although sodium monofluorophosphate is preferred, others *Trade Mark c , .. . . . _ ~6~39f~56 such as stannous fluori~e or sodium fluoridc may also be used. Conerally speaking, up to 150 and, prcferably, 0.7% by weight is desirable.
In order to illustrate the practice of this invention, the follow-ing example is included:
E~MPLE ~ -A toothpaste is prepared by mixing in a steam-jaclceted kettle equipped with a gate mixer, 0.1 grams of sodium carboxy methyl cellulose and 52.5 grams of glycerin. The temperature in the jacket is raised to about ~ I
90 C. 5.2 grams of aerosil, 1 gram of polyethlene glycol solvent, 12.5 grams of ZE0, 0.5 grams of saccharin sodium and 2.02 grams of methyl paraben are ~ -then added with constant mixing. In a separate vessel one gram of sodium lauryl sulfate is dissolved in about 4 ml of water. When the solution is complete, it is added to the contents of the steam-jacketed kettle. When the temperature cools to 50 C., 0.0025 grams of FD&C Red #2, 0.001 of D&C Red #33, 0.001 grams of FD~C yellow ~6, 1 gram of cinnamon flavor and 0.7 grams of sodium monofluorophosphate are added to the resulting mixture. When the mixture is cooled to room temperature, it is a clear gel exhibiting a re-fractive index of 1.41. It is then packed into conventional toothpast tubes by simple filling procedures.
A comparison was made between the above composition utilizing precipitated silica as against a typical composition utilizing silica gel.
The results are as follows~
~Trade ~ark ,'i~, ,,;, ~ r~; ., .', , :, ~ ,; ' ~:
. .' ~ .. , .: .
1~3g656 GEL TOOTHPASTE
OF THE PRIOR ART
INVENTION COMPOSITION
(1) ABR~SI~E
INGREDIENT (a) Precipitated silica (a) Dehydrated - silica gel (~erogel) (b) Non-porous (b) Porous (c) Refractive 1.40 inde~ (c) 1.46
~)396S6 The present invention relates to compositions of matter and, more p~rticularly, the present invention relates to novel den-tal compositions which are characterized as having a clear gel consistency and exhibiting a high degree of cleansing properties. Still more particu-larly, the present invention relates to a clear gel dental composition containing a non-porous form of precipitated silica as the principal cleansing agent.
Heretofore, particulate dehydrated silica gels have been included in dentifrice compositions as an active ingredient to enhance their polishing and cleansing properties. Please see, for example, Canadian patents 835,353, 911,335 and 914,069.
We have found that these dental compositions, while providing good cleansing properties exhibit instability, e.g., loss of gel consistency, upon storage. This instability is more pronounced when therapeutic amounts of a fluoride compound such as, for example, sodium mono fluorophosphate is added to such a composition. These instabilities obviously make the dental compositions commercially less attractive.
We have now found that it is possible to formulate den-tal compositions which not only provide good cleansing and polishing of the teeth but which are also stable over long periods of time. In addition, therapeutic amounts of fluoride can be included without loss of stability.
The silicas used in the aforementloned patents are characterized as "dehydrated silica" or "Xerogel".
In contrast thereto, silicas used herein are prepared in accordance with the procedures described in United States Patents 3,110, -- 606 and 3,582,379 and available under the trade name of "ZEo-49." In Canadian Patent 835,353,-for example, the silica is prepared by treating sodium silicate with a mineral acid. After gelling, the hydrogel is dried and reduced to a small particle.
*Trade Mark , ......
1~39~S6 The precipitated silicas useful for the present invention are pro-duced by the destabilization and precipitation of silica from soluble sodium silicate by the addition of a mineral acid under carefully controlled conditions. The reactants, both silicate and acid, are dilute solutions ~-and the reaction is carried out at an elevated temperature with agitation.
The addition of reactants or the reaction rate is extremely critical as the first phase in the reaction is the development of a hydrosol. The hydrosol ~ -stage is a colloidial dispersion of the silica in a highly polymerized form of micellular development. Under the formation conditions, the micelles are in a metastable state and are the nuclei for the precipitation of the silica particles. The particles occur in discrete spherical particles or in irregularly shaped clusters of the particles called aggregates. The size of the particles and the state of aggregation are controlled by the process ~ -conditions. The particles are then separated by filtration from the aqueous medium in which they were precipitated. The filter cake is washed with water to displace the precipitation medium which contains soluble salts.
The filter cake is then dried by forced hot air and the dry powder is ground to a state suitable for use. The ultimate particles in the dry powder may vary from 100 to 300 A in diameter with surface areas ranging from 10 m /g to 300 m2/g.
The major distinguishing differences between the silica gel or xerogel products disclosed in the aforesaid Canadian patents and the pre-cipitated silicas useful for the present invention are the high concentra-tion of the reactants, the low temperature of the reaction, the fast reaction rate and the absence of agitation during the formation of the hydrogel phase.
The hydrogel phase is characterized by the infinite polymerization of the silica to the state that the liquid phase is completely encapsulated and immobilized within the framework of the solid. The hydrogel is then disin- ~ -tegrated with agitation, and the solid phase is recovered by filtration, 1~396S6 washing and drying. The dried gel is termed a xerogel which is a gel that has been separated from its mother liquor or the gel is simply "silica gel."
Sueh a gel is readily distinguishable from precipitated silicas by its high surface area, which ranges from 300 ~o 1000 m /g. The high surface area is the result of the internal porosity within the ultimate particle.
This internal porosity is due to the interconnecting channels or network formed during the hydrogel stage of the manufacturing process. In the preeipitated silicas, most of the surface area is due to the area of the external surfaee.
In a typieal embodiment of the present invention, about 1 to 20%
and, typieally, 12.5% of the precipitated silica available under the trade name l'ZEO" from J. M. Huber Corporation, Havre de Graee, Maryland, 21078, is blended together with 0.1% of sodium earboxymethyl cellulose and 1% of polyethylene glycol at a temperature of about 90 C. To enhance the wett-ability of such a eomposition, small amounts of a surfaee active agent sueh as sodium lauryl sulfate~ a small amount of a humeetant sueh as glycerine or sorbitol may also be ineluded. Optionally, a small amount of pyrogenic siliea sueh as silica aerogel may also be included as a thickening agent and to broaden the eleansing properties. In order to enhance consumer acceptance, eoloring agents and flavoring agents may also be added.
The ingredients utilized to form the gel base are not critical so long as they are eompatible with the preeipitated siliea to give an optically elear gel. That is to say, instead of sodium earboxy methyl eellulose, other - thiekening agents sueh as carboxy polymer (carbopo~) and other synthetic binders, namely silieone dioxide derivatives sueh as Zeosyl* 200, may be used.
PEG 6000*, for example, may be substituted by other stiffening agents known in the art.
A fluoride compound may be advantageously ineluded to impart anti-earies properties. Although sodium monofluorophosphate is preferred, others *Trade Mark c , .. . . . _ ~6~39f~56 such as stannous fluori~e or sodium fluoridc may also be used. Conerally speaking, up to 150 and, prcferably, 0.7% by weight is desirable.
In order to illustrate the practice of this invention, the follow-ing example is included:
E~MPLE ~ -A toothpaste is prepared by mixing in a steam-jaclceted kettle equipped with a gate mixer, 0.1 grams of sodium carboxy methyl cellulose and 52.5 grams of glycerin. The temperature in the jacket is raised to about ~ I
90 C. 5.2 grams of aerosil, 1 gram of polyethlene glycol solvent, 12.5 grams of ZE0, 0.5 grams of saccharin sodium and 2.02 grams of methyl paraben are ~ -then added with constant mixing. In a separate vessel one gram of sodium lauryl sulfate is dissolved in about 4 ml of water. When the solution is complete, it is added to the contents of the steam-jacketed kettle. When the temperature cools to 50 C., 0.0025 grams of FD&C Red #2, 0.001 of D&C Red #33, 0.001 grams of FD~C yellow ~6, 1 gram of cinnamon flavor and 0.7 grams of sodium monofluorophosphate are added to the resulting mixture. When the mixture is cooled to room temperature, it is a clear gel exhibiting a re-fractive index of 1.41. It is then packed into conventional toothpast tubes by simple filling procedures.
A comparison was made between the above composition utilizing precipitated silica as against a typical composition utilizing silica gel.
The results are as follows~
~Trade ~ark ,'i~, ,,;, ~ r~; ., .', , :, ~ ,; ' ~:
. .' ~ .. , .: .
1~3g656 GEL TOOTHPASTE
OF THE PRIOR ART
INVENTION COMPOSITION
(1) ABR~SI~E
INGREDIENT (a) Precipitated silica (a) Dehydrated - silica gel (~erogel) (b) Non-porous (b) Porous (c) Refractive 1.40 inde~ (c) 1.46
(2) SUPPLE~DENTARY Aerosil 200 Pyrogenic ABRASIVE (Aerogel) silica INGREDIENT
(3) REFRACTIVE INDEX 1-456 1.480 OF THE GEL
~4) TRANSPARENCY* Clear transparent Translucent (greater than o.8) (greater than 0.5 - but less than o.8) (5) FOAMING AGENT 1.0% ~-5%
(6) FOAMIN~ PROPERTY*
Foam Volume in c.c.
Immediately 10 ml. 6 ml.
Life (Stability of 8 min. 5 min.
foam) (7) AVAILABLE FLUORIDE 80-85 ppm as MFP 25-84 ppm as SnF2 (8) DENTIN ABRASION App. 350-45 150-500 estimated * TRANSPARENCY TEST:
.
Translucency values were derived from differences in reflectance with alternate use of black and white surface behind 1.6 mm. cell. The arbitrary translucency index Tl is defined as being equal to 1-AR where AR:
Absorbency with white backing Absorbency with black backing measured at 660 mp ** Trade Mark ~5~
A~
.~ .. . . . . . . . ..
~39656 Tl increases with increasing transparency Tl 0-0.5 = considered opaque Greater than 0.5 = translucent Greater than 0.8 = transparent * FOAMING PROPERTIES: ~ -2 gm. of sample is taken into a test tube, add 20 ml. of distilled water and shake the tube up and down for 1 minute. The foam volume is record-ed immediately and the stability of the foam is recorded in minutes, until it completely subsides.
It appears the instant formulation is e-qual or even superior in foam volume and exhibits a more stable foam.
The increased abrasion value is probably due to the difference in structure and internal surface area between silica zerogel and precipitated silica.
:. ; . . . , : .
~4) TRANSPARENCY* Clear transparent Translucent (greater than o.8) (greater than 0.5 - but less than o.8) (5) FOAMING AGENT 1.0% ~-5%
(6) FOAMIN~ PROPERTY*
Foam Volume in c.c.
Immediately 10 ml. 6 ml.
Life (Stability of 8 min. 5 min.
foam) (7) AVAILABLE FLUORIDE 80-85 ppm as MFP 25-84 ppm as SnF2 (8) DENTIN ABRASION App. 350-45 150-500 estimated * TRANSPARENCY TEST:
.
Translucency values were derived from differences in reflectance with alternate use of black and white surface behind 1.6 mm. cell. The arbitrary translucency index Tl is defined as being equal to 1-AR where AR:
Absorbency with white backing Absorbency with black backing measured at 660 mp ** Trade Mark ~5~
A~
.~ .. . . . . . . . ..
~39656 Tl increases with increasing transparency Tl 0-0.5 = considered opaque Greater than 0.5 = translucent Greater than 0.8 = transparent * FOAMING PROPERTIES: ~ -2 gm. of sample is taken into a test tube, add 20 ml. of distilled water and shake the tube up and down for 1 minute. The foam volume is record-ed immediately and the stability of the foam is recorded in minutes, until it completely subsides.
It appears the instant formulation is e-qual or even superior in foam volume and exhibits a more stable foam.
The increased abrasion value is probably due to the difference in structure and internal surface area between silica zerogel and precipitated silica.
:. ; . . . , : .
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A clear gel-like dental composition for cleaning the teeth com-prising as the active ingredient about 10 - 15% by weight of a precipitated silica, said silica being produced by the destabilization and precipitation of silica from soluble sodium silicate by the addition of a mineral acid and having a particle size ranging from 100 - 300 Angstrom units in diameter and having a surface area ranging from 10 m2/g to 300 m2/g.
2. A composition according to Claim 1 wherein the amount of the precipitated silica is about 12.5% by weight.
3. A composition according to any one of Claim 1 or 2 wherein the composition also contain flavouring agents.
4. A composition according to Claim 1 containing up to 1% by weight of a fluoride compound.
5. A compound according to Claim 4 wherein the fluoride compound is sodium monoflurophosphate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA230,362A CA1039656A (en) | 1975-06-27 | 1975-06-27 | Clear gel dental compositions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA230,362A CA1039656A (en) | 1975-06-27 | 1975-06-27 | Clear gel dental compositions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1039656A true CA1039656A (en) | 1978-10-03 |
Family
ID=4103462
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA230,362A Expired CA1039656A (en) | 1975-06-27 | 1975-06-27 | Clear gel dental compositions |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1039656A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0543442A1 (en) * | 1991-11-19 | 1993-05-26 | Unilever N.V. | Liquid dentifrices |
-
1975
- 1975-06-27 CA CA230,362A patent/CA1039656A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0543442A1 (en) * | 1991-11-19 | 1993-05-26 | Unilever N.V. | Liquid dentifrices |
| US5310543A (en) * | 1991-11-19 | 1994-05-10 | Chesebrough-Pond's Usa Co., Division Of Conopco, Inc. | Liquid dentifrices |
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