FIELD OF THE INVENTION
The present invention relates to a dentifrice composition. More particularly, the
present invention relates to a calcium carbonate based dentifrice composition
comprising a high molecular weight polyethylene glycol (PEG) and sodium
carboxymethyl cellulose (SCMC), and a process for preparing the same.
BACKGROUND OF THE INVENTION
Dentifrices are agents used along with a toothbrush to clean and polish teeth.
Dentifrice compositions generally contain abrasives, humectants, water, binders,
flavours, sweeteners, and preservatives.
A binder is one of the most important ingredients in a dentifrice composition as it
not only binds all the other components but also provides consistency, texture and
shape to the dentifrice composition after it is extruded from the tube, onto the
tooth brush. Additionally, it enables the solid phase to be adequately suspended in
the liquid phase to prevent phase separation. Examples of binders used in
dentifrice compositions include PEG, SCMC (henceforth referred to as CMC),
Hydroxyethyl cellulose, Carrageenan, Xanthan gum, Sodium alginate, etc.
Moreover, PEG also acts as a humectant in dentifrice compositions to prevent loss
of water and hardening of the product upon exposure to air.
Polyethylene glycol (PEG) is a polyether compound with applications ranging
from industrial manufacturing to medicine. PEG is also known as polyethylene
oxide (PEO) or polyoxyethylene (POE), and is commonly expressed as
H−(O−CH2−CH2)n−OH. PEGs are prepared by polymerization of ethylene
oxide and are commercially available over a wide range of molecular weights
from 300 g/mol to 10,000,000 g/mol. While PEGs with different molecular
weights find use in different applications, and have different physical properties
(e.g. viscosity) due to chain length effects, their chemical properties are nearly
identical. Typically, the lower molecular weight polyethylene glycols, i.e. having
a molecular weight below 800, which are normally liquids, impart a bitter taste
and a pronounced bitter after-taste, whereas higher molecular weight ones, i.e.
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those having molecular weight above 1200, taste relatively bland with no
pronounced after-taste.
PEG is widely used in dentifrice compositions as a binder and humectant. United
States Patent US 2501145 A discloses a composition containing in cream form,
sodium perborate, 10-50 parts, polyethylene glycol (PEG) having an average
molecular weight of from about 300 to about 2000, 38-85 parts, and an
inactivating agent selected from the group consisting of benzaldehyde,
oxyderivatives thereof and cinnamic aldehyde in an amount from about 0.1 to
about 0.5 part. Likewise, United States Patent US 2991229 A discloses a
toothpaste composition comprising Po1y(ethylene oxide) 0.001-5%, Waterinsoluble
abrasive 20-75%, Liquid vehicle 20-75%, and Anti-caries agent 0.5-5%.
United States patent US 3689637 A discloses that high molecular weight PEGs
(above 800 and preferably 1000-6000) have been used in toothpastes, in order to
obtain good texture, particularly with CMC. According to this document, the use
of a relatively small amount of the high molecular weight PEG has a significant
impact on the texture, translucency, and transparency of the dentifrice. The
dentifrice contains about 1 percent to 15 percent, preferably about 2 percent to 8
percent, of the high molecular weight polyethylene glycol. Despite the high
degree of cohesiveness provided by the polyethylene glycol, the toothpaste is very
quickly dispersed in the mouth during tooth brushing.
The inventors of the present invention sought to prepare a chalk (calcium
carbonate) based dentifrice composition comprising CMC and PEG, particularly
PEG 32, which has a number average molecular weight of about 1500. A
dentifrice composition with such a combination, due to undesirable attributes such
as less foam and syneresis or oozing out of polyethylene glycol from the product,
has never been formulated in the prior art. Surprisingly, the present inventors have
discovered that by limiting the amount of PEG 32 in a chalk based dentifrice
composition, within a certain range, the drawbacks such as less foam and
syneresis can be effectively mitigated.
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SUMMARY OF THE INVENTION
The present invention is broadly related to a dentifrice composition comprising
CMC, wherein the drawbacks, such as syneresis and low foam are overcome by
modulating the concentration of PEG 32. The terms “PEG 32” and “PEG 1500”
mean essentially the same thing and can be used interchangeably.
In accordance with an embodiment of the invention, there is provided a dentifrice
composition, comprising: (a) Calcium carbonate in an amount in the range from
36.00 to 49.50%; (b) PEG 32 in an amount in the range from 0 to 2%; (c) CMC in
an amount in the range from 0.30 to 0.80%; (d) additives; and (e) water.
The additives are selected from the group consisting of an abrasive; a humectant;
a surfactant; a flavour; a sweetener; a preservative; a herbal extract; and sodium
silicate.
Preferably, the abrasive is present in an amount of 2.25 to 4.25%, the humectant is
present in an amount of 25.00 to 38.00%, the surfactant is present in an amount of
1.50 to 2.40%, the flavour is present in an amount of 0.60 to 1.20%, the sweetener
is present in an amount of 0.15 to 0.25%, the preservative is present in an amount
of 0.11 to 0.25%, the herbal extract is present in an amount of 0.10 to 0.50%, and
sodium silicate is present in an amount of 0.50 to 0.80%.
In accordance with another embodiment of the invention, there is provided a
process for preparing a dentifrice composition, said process comprising the steps
of:
(a) adding water and humectant to a mixing vessel and mixing;
(b) adding CMC to the mixture of step a and mixing;
(c) adding sweetener, herbal extract and preservatives to the mixture
of step b and mixing;
(d) adding PEG 32 and sodium silicate to the mixture of step c and
mixing;
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(e) adding abrasive and calcium carbonate to the mixture of step d and
mixing;
(f) adding surfactant to the mixture of step e and mixing; and
(g) adding flavor to the mixture of step f and mixing to form the
dentifrice composition.
.BRIEF DESCRIPTION OF DRAWINGS
Figure 1. is a graph of cohesive value of dentifrice compositions with varying
amounts of CMC and PEG 32.
Figure 2. is a graph of the foam level provided by dentifrice compositions with
varying amounts of CMC and PEG 32.
Figure 3. depicts the degree of syneresis in dentifrice compositions with varying
amounts of CMC and PEG 32 at 1 hour, 8 hour and 24 hour time points.
Figure 4. illustrates shear thinning behaviour of the dentifrice compositions with
increase in shear rate.
Figure 5. is a graph of the Thixotropic study showing better structure
regeneration in a dentifrice composition comprising 2% PEG 32 than without
PEG 32.
Figure 6. is a graph of Time sweep illustrating better drying time for a dentifrice
composition comprising 2% PEG 32 than without PEG 32.
DETAILED DESCRIPTION OF THE INVENTION
Discussed below are some representative embodiments of the present invention.
The invention in its broader aspects is not limited to the specific details and
representative methods. The illustrative examples are described in this section in
connection with the embodiments and methods provided. The invention according
to its various aspects is particularly pointed out and distinctly claimed in the
attached claims read in view of this specification.
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It is to be noted that, as used in the specification and the appended claims, the
singular forms "a," "an," and "the" include plural referents unless the context
clearly dictates otherwise. Thus, for example, a reference to a composition
containing “a compound” includes a mixture of two or more compounds. It should
also be noted that the term “or” is generally employed in its sense including
“and/or” unless the content clearly dictates otherwise.
The expression of various quantities in terms of “%” or “% w/w” means the
percentage by weight of the total solution or composition unless otherwise
specified.
All cited references are incorporated herein by reference in their entireties.
Citation of any reference is not an admission regarding any determination as to its
availability as prior art to the claimed invention.
An ideal dentifrice composition has optimum spreadability, dispersibility,
cohesive value, ribbon stand-up, foaming property and flavour retention. These
objectives can be met by carefully modulating the concentrations of the
constituents of a dentifrice composition. A dentifrice composition comprising
calcium carbonate, PEG 32 and CMC, exhibits several undesirable attributes such
as low foam and syneresis. Surprisingly, the inventors of the present invention
have discovered that these drawbacks can be overcome by restricting the amount
of PEG 32 below 2%. The discovery is even more remarkable considering the fact
that PEG 32 is considered an anti-foaming agent, i.e. a substance that reduces the
foaming ability of a composition. The term “PEG 32” stands for polyethylene
Glycol, which is a polymer of ethylene glycol. The number in the name represents
the average number of ethylene glycol units. The term “PEG 1500” refers to a
polyethylene glycol having a number average molecular weight of 1500. Hence,
the terms “PEG 32” and “PEG 1500” mean essentially the same thing and can be
used interchangeably.
The inventors of the present invention disclose a dentifrice composition,
comprising: (a) Calcium carbonate in an amount in the range from 36.00 to
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49.50%; (b) PEG 32 in an amount in the range from 0 to 2%; (c) CMC in an
amount of 0.3 to 0.8%; (d) additives; and (e) water.
A dentifrice composition comprises functional additives that not only stabilize and
improve the appearance of the composition but also impart medicinal properties
for dealing with the numerous maladies of the oral cavity. Non-limiting examples
of the additives that can be used in the present invention include an abrasive; a
humectant; a surfactant; a flavour; a sweetener; a preservative, a herbal extract,
sodium silicate and so forth, each of which can be used individually or in
combination.
Preferably, the dentifrice composition of the present invention contains an
abrasive in an amount in the range from 2.25 to 4.25%. An abrasive is one of the
most important ingredients in a dentifrice composition, as it cleans and polishes
teeth by removing solid insoluble particles, debries and residual stains. Examples
of abrasives that can be used in the present invention include, but not limited to,
sodium metaphosphate, potassium metaphosphate, tricalcium phosphate,
dihydrated calcium phosphate, anhydrous dicalcium phosphate, calcium
pyrophosphate, magnesium orthophosphate, trimagnesium phosphate, calcium
carbonate, alumina, hydrated alumina, aluminum silicate, zirconium silicates,
silica, bentonite and so forth, each of which can be used individually or in
combination.
Furthermore, a dentifrice composition exposed to the environment soon hardens
due to evaporation of water. Hence, in order to prevent the loss of water and
hardening upon exposure to air, the dentifrice composition of the present
invention contains humectants selected from the group consisting of glycerine,
sorbitol, polypropylene glycol and combinations thereof in the range from 25.00
to 38.00%.
Another important constituent of a dentifrice composition is a surfactant. The term
“surfactant” used herein refers to an organic compound that is amphiphilic,
meaning it contains both hydrophobic group (their tail) and hydrophilic group
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(their head). Therefore, a surfactant contains both a water-insoluble (or oilsoluble)
component and a water-soluble component. The purpose of a surfactant is
to loosen and break down substances on the teeth that would otherwise not be
soluble, meaning they could not be dissolved and rinsed away with water.
Examples of surfactants that can be used in the present invention include, but not
limited to, sodium lauryl sulphate, cocamidopropyl betaine, sodium lauryl
sarcosinate, and sodium methyl cocoyl taurate. In a preferred embodiment the
dentifrice composition contains sodium lauryl sulphate in an amount in the range
from 1.50 to 2.40%.
Yet another important constituent of a dentifrice composition is a binder, as it
provides consistency, texture and shape to said composition after it is extruded
from the tube onto the tooth brush. The binder also enables the solid phase to be
adequately suspended in the liquid phase, to prevent phase separation. Nonlimiting
examples of binders that can be used in the present invention include
hydroxyethyl cellulose, carrageenan, xanthan gum, sodium alginate and so forth,
each of which can be used individually or in combination in an amount in the
range from 0.30 to 0.80%.
In order to make the dentifrice attractive and appealing to consumers, particularly
children, flavours and sweeteners are added. Flavours include, but not limited to,
spearmint, peppermint, wintergreen, eucalyptol oil. Further, sweeteners include,
but not limited to, saccharin, sugar alcohols, sorbitol, and xylitol. Preferably, the
flavour is present in an amount in the range from 0.60 to 1.20%, whereas the
sweetener is present in an amount of 0.15 to 0.25%.
Yet another important constituent of the dentifrice composition is a preservative,
which increases its shelf life by preventing the growth of micro-organisms such as
bacteria, viruses and fungi. Non-limiting examples of the anti-microbial
preservatives that can be used in the present invention include, potassium sorbate,
sodium benzoate, sodium methyl paraben, methyl paraben, propyl paraben,
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benzoic acid, sorbic acid and so forth, each of which can be present individually
or in combination in an amount in the range from 0.11 to 0.25%.
A number of herbal extracts can be used in the present invention as they mimic
the function of artificial chemical agents used in traditional toothpastes to fight
plaque, freshen breath and prevent gum disease. Non limiting examples include:
Aloevera: Antiseptic and anti-inflammatory, soothes, promotes healing and
reduces inflammation; Tea tree oil: Antibiotic, anaesthetic antimicrobial and
antiseptic, promotes healing and combats infection; Chitosan: Antibacterial,
promotes wound healing by combating bacteria; CO-Q10: A natural plant extract
which promotes healthy gums through increased circulation; Chamomile: Hastens
wound healing; Sage: Treats sore throats, gums and mouth ulcers; Myrrh: Treats
sore throats, mouth ulcers and gum disease; Eucalyptus: Reduces pain and eases
sore gums through its warming and mildly anaesthetic; Echinacea: Boosts
immunity against viral and other infections, relieves respiratory problems
including sore throats, aids tissue regeneration for healthy gums; Horse chestnut:
Anti-inflammatory, promotes healthy gums by reducing swelling and
inflammation; Peppermint and menthol: Antibacterial and anti-inflammatory;
Escin: Anti-inflammatory, Promotes healthy gums by reducing swelling and
inflammation; Peelu extract (Salvadora oleiodes); Akarkara extract (Anacyclus
pyrethrum); Neem leaf extract (Azadirachta indica); Olive leaf extract (Olea
europaea) and so forth. Preferably, the herbal extracts may be present individually
or in combination in an amount in the range from 0.10 to 0.50%.
Still another important component of a dentifrice composition is sodium silicate,
which controls the pH of the finished product and prevents the corrosion (rusting)
of metallic materials used in dentifrice packaging. Preferably, the dentifrice
composition of the present invention contains sodium silicate in an amount in the
range from 0.50 to 0.80%.
The present invention is more particularly described in the following non-limiting
examples that are intended as illustrations only since numerous modifications and
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variations within the scope of the present invention will be apparent to a skilled
artisan. Unless otherwise noted, all parts, percentages, and ratios reported in the
following examples are on a weight basis, and all reagents used in the examples
were obtained or made available from the chemical suppliers.
Examples 1 to 5
Table 1 lists the constituents of the dentifrice composition and their amounts. The
unit of each value is weight percent.
Table 1. Dentifrice compositions
No. Ingredients
1
% w/w
2
% w/w
3
% w/w
4
% w/w
5
% w/w
1 Calcium carbonate 36.00 40.50 45.00 47.25 49.50
2
Sorbitol solution
(non-crystalizing)
38.00 35.00 35.00 30.00 25.00
3
Sodium lauryl
sulphate
2.00 2.00 2.00 2.00 2.00
4 Silica 4.25 3.50 3.00 2.50 2.25
5
Sodium carboxy
methyl cellulose
(SCMC or CMC)
0.80 0.60 0.35 0.30 0.30
6
Polyethylene glycol
1500 (PEG 32)
2.00 1.00 0.20 0.50 1.00
7 Sodium Silicate 0.80 0.70 0.60 0.60 0.50
8 Herbal extract 0.10 0.20 0.20 0.20 0.50
9 Sodium Saccharin 0.15 0.20 0.20 0.25 0.25
10 Preservatives* 0.20 0.20 0.11 0.20 0.25
11 Flavour 1.00 1.00 1.00 1.00 1.00
12 Purified water 14.70 15.10 12.34 15.20 17.45
*Preservatives include: Sodium benzoate, Methyl paraben, Propyl paraben or
combinations thereof.
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Process for preparing the dentifrice composition
The amounts of ingredients used to prepare the dentifrice composition are
presented in table 1. Water and Sorbitol were accurately weighed and mixed in a
mixing vessel. After that, CMC was added gradually under stirring at room
temperature. ensuring that no lumps were formed. Further, sodium saccharin,
herbal extract, methyl paraben and sodium benzoate were added gradually under
stirring to afford a dispersion free of lumps. To this dispersion were added premelted
polyethylene glycol 1500 (PEG 32) and sodium silicate and mixed well.
Thereafter, silica and calcium carbonate were added gradually with high speed
stirring to afford a smooth lump free paste. Still further, sodium lauryl sulphate
powder was added to the above mixture and mixed. Finally, the mixture is cooled
below 40 °C and a flavour containing propyl paraben was added. The mixture was
further mixed under vacuum for about 10 min to obtain the dentifrice composition
of the present invention.
Spreadability Study:
Spreadability is a measure of the anti-sag behaviour when a dentifrice
composition is extruded from a tube onto a surface. The spreadability of the paste
is measured by placing the paste in between two identical petri-plates & applying
a defined pressure on it. 2.5 g of the dentifrice composition (Table 2) was placed
between two identical petri-plates and a weight of 500 g was applied on the plates
for 3 min. After that, the paste spreadability was measured using a marked scale.
It is evident from the results illustrated in table 2 that as the concentration of PEG
32 in the formulation increases its spreadability decreases. A low spreadability
value is generally associated with a good ribbon stand up.
Table 2. Effect of the concentration of PEG 32 on spreadability
No Composition Spreadability
1 0.3% CMC and 2.0% PEG 32 6.50 cm
2 0.3% CMC and 0.2% PEG 32 6.80 cm
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3 0.3% CMC and 0.0% PEG 32 7.00 cm
Paste Dispersion Study:
The dispersibility test measures the time required for a dentifrice composition to
completely disperse in water. Hence, shorter the time required for a dentifrice
composition to completely disperse in water, better is the composition. The test
was carried out on a disintegration test apparatus - Veego Digital tablet DT
apparatus, Model: VTD-DVP. A 1000 mL beaker was filled with water and
maintained at a temperature of 37 °C. The paste (2 g) was placed in a basket rack
consisting of six open ended transparent tubes. The cylindrical disks (9.5 ± 0.15
mm thick and 20.7 ± 0.15 mm in diameter and made of a suitable, transparent
plastic material having specific gravity of between 1.18 and 1.20.) were placed in
each tube. The basket rack assembly was kept on constant upward and downward
strokes at a frequency of 32 cycles per min in the immersion fluid. The time
required for the complete dispersion of the paste in the fluid was determined and
the results are presented in table 3. The paste dispersion study revealed that in the
absence of CMC a dentifrice composition with 8% PEG 32 had a dispersibility of
7-8 minutes. Further, in the presence of a fixed amount of CMC (0.3%) the
dispersibility of the composition decreases with the increase in concentration of
PEG 32.
Table 3. Measurement of Paste Dispersion for various combinations of PEG and
CMC
No Composition Time (min)
1 0.3% CMC and 2.0% PEG 32 12-13
2 0.3% CMC and 0.0% PEG 32 16-18
3 0.3% CMC and 4.0% PEG 32 10-11
4 0.3% CMC and 6.0% PEG 32 8-9
5 0.3% CMC and 8.0% PEG 32 7
6 0.0% CMC and 8.0% PEG 32 7-8
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Measurement of Cohesive Value:
A cohesion or cohesive value is a measure of the cohesive forces acting within a
dentifrice composition to hold it together. Hence, a high cohesive value is
generally associated with a strong and firm ribbon. In order to determine the
cohesive value, the sample (40 g) was placed uniformly on the disk of a Cohesion
Value (C.V.) meter from JM Engineering & Instruments, Mumbai. A thermometer
was inserted in the mass on the disc and the temperature was recorded, ensuring
that the mass was free from air pockets. The two disks were pressed such that
there was no air gap and the meter reading was set to zero. Thereafter the excess
sample coming out of the disks was wiped, the C.V. meter was switched on and
the reading at which there was discontinuity in the sample was noted. The
cohesion value measurements revealed that in the absence of CMC a dentifrice
composition with 8% PEG 32 had a cohesion value of 490. Further, as illustrated
in figure 1, in the presence of a fixed amount of CMC (0.3%), the cohesive value
of the composition decreases with an increase in concentration of PEG 32.
Measurement of Foam Height:
Foam height is a measure of the foaming ability of a dentifrice composition. In
order to measure the foam height, 5 g of the dentifrice composition was added to a
100 mL glass beaker with 10 mL of water. The beaker was covered with a watch
glass and allowed to stand for 30 minutes for completely dispersing the toothpaste
in water. The contents of the beaker were stirred with a glass rod and transferred
to a 250 mL graduated cylinder, ensuring that no foam (more than 2 mL) was
produced and no lump of the composition goes into the cylinder. The residue left
in the beaker was transferred with further portions of 5 to 6 mL of water ensuring
that all the matter in the beaker is transferred to the cylinder. The volume of the
contents in the cylinder was made up to 50 mL by adding sufficient water and the
temperature of the cylinder and its contents was raised to 30°C. Thereafter, the
contents of the cylinder were stirred with a glass rod to ensure uniform
suspension. As soon as the temperature of the contents of the cylinder reaches 30
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°C, stirring was stopped and 12 complete shakes in a vertical plane, upside down
and vice versa were performed on the cylinder. Finally, the cylinder was allowed
to stand still for 5 minutes and the volumes of (a) Foam along with water (V1) and
(b) water alone (V2) were recorded. The Foam height was then calculated in mL
as V1-V2. As illustrated in Figure 2 compositions with 2%, 4%, 6%, 8% of PEG
32 along with 0.3% of CMC generated a foam height of 460mL, 400mL, 360mL
and 350mL respectively. Composition with only 0.3% of CMC afforded a foam
height of 410 mL, whereas the one with 8% of PEG 32 without CMC produced a
foam height of 320 mL.
Study of Syneresis or oozing out:
Syneresis is a phenomenon wherein the flavour, water and other water-soluble
components separate or ooze out from the main semi-solid or paste phase on
storage. Hence, a stable dentifrice composition should be free from the
phenomenon of syneresis. In order to determine the degree of syneresis in a
dentifrice composition, a freshly prepared dentifrice composition was squeezed
out onto a piece of paper and allowed to stand for 24 hours. As illustrated in
figure 3, the dentifrice compositions with varying amounts of CMC and PEG 32
were observed at 1 hour, 8 hour and 24 hour time points respectively. The
formulations comprising 0 to 2% PEG 32 along with 0.3% CMC exhibited the
least syneresis, whereas the degree of syneresis in formulations comprising 0.3%
CMC increased as the concentration of PEG 32 increased.
Rheological study:
Rheological study was performed to evaluate the deformation & flow
behaviour/properties of the toothpaste. The rheological parameters of the
dentifrice composition, such as flow curve, thixotropic flow and time sweep were
studied.
Flow curve: This study was carried out to evaluate the flow behaviour of the
toothpaste at applied shear rate. The study was carried out on Anton-Paar Modular
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Compact Rheometer- MCR-302 and the following dentifrice compositions i.e.
Sample O (without PEG) and Sample B (with PEG) were evaluated (Table 4).
Table 4. Dentifrice Compositions
No. Ingredients name Sample O
% w/w
Sample B
% w/w
1 Calcium carbonate 45.00 45.00
2
Sorbitol solution (noncrystalizing)
35.00 35.00
3 Sodium lauryl sulphate 2.00 2.00
4 Silica 3.00 3.00
5
Sodium carboxy methyl
cellulose
0.35 0.35
6
Polyethylene glycol 1500 (PEG
32)
0.00 2.00
7 Sodium Silicate 0.60 0.60
8 Herbal extract 0.20 0.20
9 Sodium Saccharin 0.20 0.20
10 Preservatives 0.11 0.11
11 Flavour 1.00 1.00
12 Purified water 12.54 10.54
The flow behaviours of the dentifrice compositions were analyzed by running the
samples for shear rate sweep in the range from 2 to 100 s-1, at room temperature.
Shear rate is the rate at which a progressive shearing deformation is applied to a
material. As depicted in the figure 4, the dentifrice samples (Sample O and
Sample B) show shear thinning behaviour with increase of shear rate. Sharp
viscosity change occurred around 60 s-1 and thereafter a gradual change in
viscosity was observed.
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Thixotropy study: This study was carried out to evaluate the time-dependent
shear thinning of the dentifrice composition. The study was carried out on Anton-
Paar Modular Compact Rheometer- MCR-302 and the following dentifrice
compositions i.e. Sample O (without PEG) and Sample B (with PEG) were
evaluated (Table 4).
The experiment was performed in the following three intervals: (1) shear rate
ramp of 2 to 100 s-1 for 165 s; (2) a constant shear of 100 s-1 for 50 s; and (3)
shear rate ramp from 100 to 2 s-1. Figure 5 illustrates the thixotropic properties of
the two dentifrice compositions (Sample O and Sample B).
Time sweep study (drying): The study was carried out to determine the drying
time of the toothpaste. The experiment was carried out on Anton-Paar Modular
Compact Rheometer- MCR-302 and the following dentifrice compositions i.e.
Sample O (without PEG) and Sample B (with PEG) were evaluated (Table 4).
Time sweep was performed at a constant strain (0.02%) and angular frequency (5
rad/s) to simulate the drying time of toothpaste samples after extruding it from the
tube. A higher thixotropy index translates into lesser regeneration of structure. In
the practical usage of a dentifrice composition, the structure regeneration is a
useful property so that a dentifrice composition can be placed on brush after
extruding it from a tube without sinking into the toothbrush bristles. As illustrated
in figure 6 the time sweep drying started after around 250 s for sample O (without
PEG), and after around 260 seconds for sample B (with PEG).
While particular embodiments of the present invention have been illustrated and
described, it would be obvious to those skilled in the art that various other
changes and modifications can be made without departing from the spirit and
scope of the invention. It is thereof intended to cover in the appended claims such
changes and modifications that are within the scope of the invention.

We Claim:
1. A dentifrice composition, comprising: (a) Calcium carbonate in an amount
in the range from 36.00 to 49.50%; (b) PEG 32 in an amount in the range
from 0 to 2%; (c) CMC in an amount in the range from 0.30 to 0.80%; (d)
additives; and (e) water.
2. The dentifrice composition, as claimed in claim 1, wherein the additive is
selected from the group consisting of an abrasive; a humectant; a
surfactant; a flavor; a sweetener; a preservative, a herbal extract, sodium
silicate and combinations thereof.
3. The dentifrice composition as claimed in claim 2, wherein the abrasive is
selected from the group consisting of sodium metaphosphate, potassium
metaphosphate, tricalcium phosphate, dihydrated calcium phosphate,
anhydrous dicalcium phosphate, calcium pyrophosphate, magnesium
orthophosphate, trimagnesium phosphate, calcium carbonate, alumina,
hydrated alumina, aluminum silicate, zirconium silicates, silica, bentonite,
and combinations thereof and present in an amount in the range from 2.25
to 4.25%.
4. The dentifrice composition as claimed in claim 2, wherein the humectant
is selected from the group consisting of glycerine, sorbitol, polypropylene
glycol and combinations thereof and present in an amount in the range
from 25.00 to 38.00%.
5. The dentifrice composition as claimed in claim 2, wherein the surfactant is
selected from the group consisting of anionic surfactants, amphoteric
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surfactants, nonionic surfactants, sodium lauryl sulphate, cocamidopropyl
betaine, sodium lauryl sarcosinate, sodium methyl cocoyl taurate and
combinations thereof and present in an amount in the range from 1.50 to
2.40%.
6. The dentifrice composition as claimed in claim 2, wherein the flavor is
selected from the group consisting of spearmint, peppermint, wintergreen,
eucalyptol oil and combinations thereof and present in an amount in the
range from 0.60 to 1.20%.
7. The dentifrice composition as claimed in claim 2, wherein the sweetener is
selected from the group consisting of saccharin, sugar alcohols, sorbitol,
xylitol, and combinations thereof and present in an amount in the range
from 0.15 to 0.25%.
8. The dentifrice composition as claimed in claim 2, wherein the preservative
is selected from the group consisting of methyl paraben, propyl paraben,
sodium benzoate and combinations thereof and present in an amount in the
range from 0.11 to 0.25%.
9. The dentifrice composition as claimed in claim 2, wherein the herbal
extract is selected from the group consisting of Peelu extract (Salvadora
oleiodes), Akarkara extract (Anacyclus pyrethrum), Neem leaf extract
(Azadirachta indica), Olive leaf extract (Olea europaea) and combinations
thereof and present in an amount in the range from 0.10 to 0.50%.
10. The dentifrice composition as claimed in claim 2, wherein sodium silicate
is present in an amount in the range from 0.50 to 0.80%.
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11. A process for preparing a dentifrice composition as claimed in claims 2 to
10, comprising the steps of:
(a) adding water and humectant to a mixing vessel and mixing;
(b) adding CMC to the mixture of step a and mixing;
(c) adding sweetener, herbal extract and preservatives to the mixture
of step b and mixing;
(d) adding PEG 32 and sodium silicate to the mixture of step c and
mixing;
(e) adding abrasive and calcium carbonate to the mixture of step d and
mixing;
(f) adding surfactant to the mixture of step e and mixing;
(g) adding flavor to the mixture of step f and mixing to form the
dentifrice composition.