NOVEL MOISTURE BARRIERIMMEDIATE RELEASE FILM COATING COMPOSITIONS

FIELD OF INVENTION
The present invention relates to immediate release film coating compositions with excellent
moisture barrier properties for use in film coating o substrates like pharmaceutical materials,
food, confectionery forms, nutritional supplements, agricultural seeds and the like.
BACKGROUND OF INVENTION
Many therapeutic ingredients are sensitive to moisture and undergo degradation when in contact
with moisture from the atmosphere. Moreover, the humidity level of different places is different.
Thus, relying on packaging material isn't sufficient to prevent therapeutic ingredients from
moisture degradation. A moisture barrier coating on a substrate prevents or delays the substance
from being degraded by moisture.
Certain film coating compositions are said to have moisture barrier properties. For instance,
WO199600 1874 discloses a moisture barrier film coating composition comprising polyvinyl
alcohol and soya lecithin. WO0104195 discloses film coating compositions comprising poly
vinyl alcohol or poly ethylene glycol or Glycerol in combination with talc and soya lecithin.
Certain film coating compositions with PVA and stearic acid are also reported to have moisture
barrier properties.
However, there are certain disadvantages of the prior art compositions asthe compositions which
contain soya lecithin are highly hygroscopic, tends to pick up moisture, andhence the material
stability is very poor with low shelf life. It also tends to become pale yellow to dark yellow on
storage, thus interfering with the color shade of the final product. Compositions which use
polyvinyl alcohol (PVA) in solution form render tackiness to the final coating dispersion. The
increased tackiness of the final composition may cause variety of problems including tablet
sticking, agglomeration and may lead to variation in batches.
WO2010132204disclosesa moisture barrier immediate release film coating composition
comprising a polymer, a polymer with pH dependent solubility, optionally plasticizer and/or
glidant, alkalizing agent, emulsifier and pigment. However this process includes glycerin (having
hygroscopic properties) in higher amount of 6-12%, therefore composition could possibly retain
some amount of water.
WO20061 11981discloses a coating composition capable of forming an immediate release
moisture barrier film coat for pharmaceutical substrates like tablets and the like, comprising
polyvinyl alcohol and self emulsifyingself-emulsifyingglyceryl monostearate as an anti-tack
agent. However this process includes use of hot water for reconstitution and final film
coating,which is cumbersome in an industrial set up and not suitable for heat sensitive materials
Hence, there is still a need for a moisture barrier coating that is quick and easy to reconstitute, is
not tacky and easy to handle.
OBJECT OF INVENTION
An object of the present invention is to provide a novel immediate release, moisture barrier, nontacky
film coating composition of PVA that is completely dispersed at ambient temperature and
the process for producing the same.
SUMMARY OF INVENTION
It has been surprisingly found that the use of plasticizer in combination withwaxyemulsifierand a
hydrophobic barrier forming material and the polymer results in a composition giving smooth
coating, which is non-tacky and disperses easily in ambient temperature. Further the resultant
film exhibits good adhesion and tensile strength.
DETAILED DESCRIPTION
Unless otherwise stated all terms used in the following description, shall constitute the same
meaning as understood by a person skilled in the art. All terms used here in the specification
carry the same meaning as in common scientific parlance.
Film coating is the process whereby a tablet, capsule, or pellet is surrounded by a thin layer of
polymeric material. Coating tablet with a thin polymeric film is commonly performed to modify
drug release, mask the taste of therapeutic agents, to enhance the stability of the drug within the
gastrointestinal fluids or may be used for pure aesthetic reasons.
The present invention provides a novel moisture barrier, immediate release film coating
composition comprising a polymer, a waxy emulsifier, a plasticizer, a wetting agent, a
hydrophobic agent,and optionally an opacifier, a pigment, a diluent, lubricant or other
pharmaceutically acceptable excipients.
For the purpose of this invention 'hydrophobic polymer composite base' comprises the dry mass
obtained by mixing the polymer with heated plasticizer, emulsifier, hydrophobic agent and
wetting agent.
For the purpose of present invention, 'ambient temperature' shall be understood to mean
temperatures generally in the range of from about 20°C (68°F) to about 30°C (86°F) +/-3°C.
An immediate release film coating composition of the present invention comprises a dry
hydrophobic polymer composite base along with pharmaceutically acceptable excipients.
The dry hydrophobic polymer composite base of present invention comprises a polymer, awaxy
emulsifier, a plasticizer, a wetting agent and a hydrophobic agent.
The novel immediate release film coating composition of the present invention includes a
polymer which forms a good film lacks toxicity and has a suitable solubility profile upon
ingestion. The film must provide a tough, yet elastic film even in the presence of powdered
additives such as pigments. The film must be stable to heat, light, moisture and be free from
undesirable taste and odor.
The polymer may be selected from the group comprising polyvinyl alcohol (PVA), copolymers
based on PVA, polyvinylpyrrolidone-vinyl acetate copolymer (copovidone), polyvinylacetate
phthalate, methacrylic acid copolymers, hypromellose (hydroxypropylmethyl cellulose),
hydroxypropylcellulose, sodium carboxymethyl cellulose, ethyl cellulose. The polymer may be
preferably polyvinyl alcohol.
Polyvinyl alcohol is an odorless and tasteless, translucent, white or cream colored granular
powder. All grades of polyvinyl alcohol may be used in the present invention.
The amount of polymer used in the composition of the present invention may be range of 55
to80%, preferably 60 to 75% by weight of the hydrophobic polymer composite base.
Plasticizer of the present invention may be selected from the group comprising phthalate esters,
phosphate esters, and other esters like citrates, stearates, sebacate, oleate, oils, glycerols, glycols
etc. Preferably, the plasticizer of the present invention is selected from the group comprising
polyethylene glycol, ethyl phthalate, methyl phthalate, propylene glycol, fractionated coconut
oil, lecithin, castor oil, dibutylsebacate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate,
triacetin, liquid paraffin, triethyl citrate, and combinations thereof. More preferably, the
plasticizer is dibutylsebacate, diethyl phthalate, and dibutyl phthalate.
The amount of plasticizer used in the composition of the present invention may be range of lOto
25% w/w, preferably 10-20% by weight of the hydrophobic polymer composite base.
The composition of the present invention comprises a waxy emulsifier. A non-limiting list of
materials that may be used as 'waxy emulsifier' includes glyceryl monostearate,
glycerylbehenate (e.g. Compritol 888 ATO), glycerylpalmitostearate (e.g. Precirol ATO 05),
sorbitan ester (e.g. sorbitan monopalmitate—Span 40), palmitic acid, polyoxyethylene alkyl
ether (e.g. Cremophor AG; Brij 52; Brij 72; Volpo S2; and Ethylan 2512),
lauroylpolyoxylglyceride (e.g. Gelucire 44/14) and stearoylpolyoxylglyceride (e.g. Gelucire
50/13), ceresin, cetostearyl alcohol, cetyl alcohol, docusate sodium, ethyl maltol, ethylene glycol
stearates, glycerylmonooleate, lanolin, myristic acid, petrolatum/lanolin alcohol, polyoxyl 6
stearate, polyoxyl 8 stearate, propylene glycol monostearate, sorbitan tristearate, sodium
stearylfumarate, stearyl alcohol, hydrogenated vegetable oil, carnauba wax, microcrystalline wax
and zinc stearate, and the like.
The amount of waxy emulsifier used in the composition may be in the range of 0.3% w/w to 10
% w/w, preferably in the range of 0.5 % w/w to 5% by weight of the hydrophobic polymer
composite base.
Wetting agents of the present invention may be selected from the group comprising Tween 20
(polysorbate 20 or poloxyethylene (20) sorbitan monolaurate), Tween 40 (polysorbate 40 or
polyoxyethylene (20) sorbitan monopalmitate), Tween 60 (polysorbate 60 or polyoxyethylene
(20) sorbitan monostearate), Tween 80 (polysorbate 80 or polyoxyethylene (20) sorbitan
monoleate), sodium lauryl sulphate and combinations thereof.Preferably the wetting agent is
polysorbate 80.
The amount of wetting agent used in the composition of the present invention may be in the
range of 0.3% w/w to 10% w/w, preferably in the range of 0.5% w/w to 5% by weight of the
hydrophobic polymer composite base.
The hydrophobic agent gives moisture barrier properties to the film coating composition. Further
the hydrophobic agent gives smooth flowing properties to film coating composition.The
Hydrophobic agent of the present invention may be selected from the group comprising Stearic
acid, Sodium stearate, calcium stearate, zinc stearate, glyceryl palmitostearate.Preferably the
hydrophobic agent is stearic acid.
The amount of hydrophobic agent used in the composition of the present invention may be in the
range of 1% w/w to 25% w/w, preferably in the range of 5% w/w to 20% by weight of the
hydrophobic polymer composite base.
The composition of the present invention may additionally comprise other ingredients such as an
opacifier, a colorant, a diluent, a lubricant, a flavoring agent and/or a sweetening agent etc.
Opacifiers of the present invention may be selected from the group comprising titanium dioxide,
zinc oxide, calcium carbonate, magnesium oxide and the like.
A pigment may be used to provide color to the film coating. For instance, pigments of the
present invention may include iron oxide colors, Lake or soluble colors, natural colors, candurin
colorsand the like or any food approved colors or dyes or combinations thereof.
Diluent of the present invention may include Tri basic calcium phosphate, Micro-crystalline
cellulose, calcium phosphateand the like.
Lubricants of the present invention may be selected from the group comprising magnesium
stearate, calcium stearate, zinc stearate, stearic acid, mineral oil, and combinations thereof.
Sweeteners of the present invention may be selected from the group comprising glucose,
fructose, sorbitol, aspartame, glycerol, saccharin, xylitol and the like.
Flavoring agents of the present invention may be selected from the group comprising powder,
liquid, encapsulated flavors either natural or syntheticorigin.
Substrates of the present invention comprise but are not limited to pharmaceutical materials,
nutritional supplements, food, confectionery forms, agricultural seeds, and the like.
The present invention provides a composition for coating , wherein the a dry hydrophobic
polymer composite base present in the range from about 55 to about 80%, preferably in the
range of 60 % w/w to 75%, with other pharmaceutical excipients further comprising alubricant is
present in the range of 1-15% w/w,and optionally an opacifier is present in the range of 0.1-25%
w/w, a pigment is present in the range of 0.1 - 15% w/w a diluent is present in the range of
0.1-15% w/w, or combinations thereof along with other pharmaceutically acceptable excipients.
In another aspect the composition of the present invention may be prepared by a process
comprising the steps of:
1. combining the liquefied plasticizer with the waxy emulsifier, hydrophobic agent and
wetting agent;
2. heating the above said mixture to obtain a homogenous liquid dispersion;
3. adding the polymer to the heated mixture of step 1 to obtain the hydrophobic polymer
composite base in dry powder form;
4. optionally adding other pharmaceutical excipients to obtain the composition of the
present invention.
The process of preparing the composition of the present invention includes combining the axy
emulsifier and wetting agent with the liquefied plasticizer. The combination may be achieved by
several processes such as heating, stirring etc. The resultant mixture obtained on combining the
liquefied plasticizer with the waxy emulsifier and hydrophobic agent may be heated in the
temperature range of about 60-90 °C (degree Celsius), more preferably about 70-80°C, for a
period of 5-10 min to obtain a homogenous liquid dispersion.
The polymer of the present invention is added to the homogenous liquid dispersion to obtain the
hydrophobic polymer composite base. In addition other pharmaceutical acceptable excipients
may be added to polymer composite base.
In another embodiment, the present invention provides a method for coating substrates
comprising reconstituting the film coating composition into water at ambient temperature to form
an aqueous coating solution, applying the coating solution onto the substrates to form a film
coating on the substrates, and drying the film coating on said substrates.
In another aspect of the invention, the composition of the present invention is reconstituted
inpurified water, de-mineralized water, andlike.The amount of solidpresent after reconstitution
may be in the range of 10-40% w/v, preferably 15to 30% w/v.
The hydrophobic polymer composite base of the present invention may be coated by methods
such as simple pan coating, fluidized bed coating, pans with one-way air flow through the tablet
bed and the like.
The film coating process may be carried out in conventional pan. Operation variables such as
speed of pan, rotation, angle of pan axis, and temperature and humidity control, optimum spray
rate may beadjusted whichhelp in increasing the efficiency of the process and obtaining desired
coating effect. Surprisingly inventive composition displayed good spray delivery rates even at
such high solids in the coating suspension.
For instance, the composite base or the composition of the present invention may be sprayed by
adapting the following coating parameters, such as Inlet air temperature in the range of 50-70
degree Celsius, Tablet bed temperature in the range of 30-50 degree Celsius, suitable pump
speed, pan speed, an atomizing air pressure in the range of 1.4-3.0KG/cm sq. as per requirement
of lot size to be coated.
Without being limited by theory, the composition of the present invention uses a hydrophobic
plasticizer in combination with other ingredients and PVA, which results in a composition which
provides a smooth coating, which is non-tacky and disperses easily in ambient temperature.
Further the resultant film exhibits good adhesion and tensile strength. Moreover, the process of
preparing the composition of the present invention, using a combination of heating and
maintaining the mixture at appropriate temperatures and addition of the composition in sequence.
It is postulated that the plasticizer interacts with the waxy emulsifier thereby surprisingly
reducing the relative size of GMS and hydrophobicity of mixture. Such a mixture is easily
dispersed in the polymer, thereby easing reconstitution. The composition of the present invention
is highly effective in spite of the presence of another hydrophobic agent.
Hence, the composition of the present invention is synergistic, is easily dispersible, readily
reconstitutable and eliminates the problems of prior art. Further the composition of the present
invention provides a highly effective moisture barrier.
In another aspect, the present invention relates to the intimate mixture obtained by heating the
plasticizer, hydrophobic agent and wetting agent to a temperature of about 60-85°C and
subsequent addition of waxy emuisifier with continuous mixing of 10-15 minutes. The intimate
mixture thus obtained has a desirable particle size. This intimate mixture is capable of freely
passing through #120 mesh to #325 mesh, 38 micron, 28 micron sieves. Subsequently addition of
polymer to this intimate mixture provides granules having ranges of #100 mesh to #120 mesh.
In another aspect, the composition of the present invention has a moisture vapor transmission
rate (MVTR) in the range of 0.004-0.009 grams water/day/cm2, much lower than the data
obtained for HPMC based films.
ADVANTAGES
1. The present invention uses a wetting agent with a waxy emuisifier and a liquefied
plasticizer in raised temperature, thereby dissolving the waxy emuisifier easily and hence
eliminating the problem of prior art.
2. The composition of the present invention may be adapted to provide colorless and
transparent film coat to the materials with the enhanced film properties like finish,
aesthetics, moisture barrier and luster.
3. The composition of the present invention has minimum tackiness, good adhesion, good
tensile strength, high stability and high percentage of reconstitution.
4. The reconstitution of composition of the present invention is simple and the high solid
content does not lead to any viscosity problem for spray and does not dry at the orifice of
the spray gun and the coating can easily be completed very quickly.
5. The reconstitution of the composition of the present invention may be carried out in
water, and thereby eliminates the use of harmful organic solvents and vapors.
6. The composition of the present invention provides a uniform and nearly perfect coat in
relatively less time.
7. High solid content of the present composition helps to build up necessary weight and
coating thickness quicker than other compositions thus increasing the speed of the
process and thereby decreases the time consumed and is more economic.
8. During reconstitution of the composition, there is no sedimentation or floating of the
particles thereby eliminating continuous stirring. Thus the compositions of the present
invention are highly stable with respect to storing after reconstitution for long hours.
9. The formulation of the present invention solves the problems of prior art, with regards to
the use of glycerol monostearate in a composition.
10. The composition of the present invention reduces the dispersion time of the composition
and renders ease of constitution. The composition of the present invention is reconstituted
within a time period of 20-25 minutes, whereas the compositions of prior art are
reconstituted only in about 35-40 minutes.
11. The solid content of the composition of the present invention is much higher than that of
prior art.
The invention illustratively disclosed herein suitably may be practiced in the absence of any
component, ingredient, or step which is not specifically disclosed herein. Several examples are
set forth below to further illustrate the nature of the invention and the manner of carrying it out.
However, the invention should not be considered as being limited to the details thereof.
EXAMPLES
The present invention will next be described in further detail based on examples and comparative
examples, although the present invention shall not be limited by the following examples. All
units and percentages in the examples are by weight.
Example 1 :
Process of preparation of hydrophobic polymer composite base comprises of heating 39.31% of
diethyl phthalate to 65degree Celsius and adding 13.95% of Glyceryl monostearate,
9.74%ofPolysorbate 80 and 37.00% of Stearic acid to form a homogenous liquid dispersion.
Take 33% w/w of the above liquid dispersion (at a temperature 70-80°C) and mix with 67% w/w
poly vinyl alcohol to prepare the desired hydrophobic polymer composite base. The same is
gradually cooled to room temperature to obtain a dry powder base. The powder obtained is sifted
through sieve of 40 mesh to ensure the absence of lumps or agglomerates. The final composition
of the dry hydrophobic polymer composite base thus obtained is given in table 1.
Table 1
This powder is reconstituted in pharmaceutically acceptable solvent (e.g. water) at ambient
temperature (20°Cto 30°C) and the suspension thus obtained is used as film coating composition
to coat various substrates. The solid content of the re-dispersed hydrophobic polymer composite
base is about 6 to 9% w/v. The film coating can be applied as part of a pan coating or spray
coating process commonly used to coat such articles.
In this case types of tablet used were medium sized, round, plane on both sides with sharp edges
with diameter 10mm, thickness 5mm and hardness of core 4.2 kg/cm sq.
Example 2 :
Process of preparation of hydrophobic polymer composite base comprises of heating 43.84% of
diethyl phthalate to 65degree Celsius and adding 9.74% of Glyceryl monostearate,
9.71%ofPolysorbate 80 and 36.71% of Stearic acid to form a homogenous liquid dispersion.
Take 33% w/w of the above liquid dispersion (at a temperature 70-80°C) and mix with 67% w/w
poly vinyl alcohol to prepare the desired hydrophobic polymer composite base. The same is
gradually cooled to room temperature to obtain a dry powder base. The powder obtained is sifted
through sieve of 40 mesh to ensure the absence of lumps or agglomerates. The final composition
of the dry hydrophobic polymer composite base thus obtained is given in table 2
Table 2
Powder is sifted, reconstituted, sprayed on tablet as explained in example 1
Example 3 :
Process of preparation of hydrophobic polymer composite base comprises of heating 36.86% of
diethyl phthalate to 65degree Celsius and adding 7.96% of Glyceryl monostearate, 8.16% of
Polysorbate 80 and 47.02% of Stearic acid to form liquid dispersion
Take 37% w/w of the above liquid dispersion (at a temperature 70-80°C) and mix with 63% w/w
poly vinyl alcohol to prepare the desired hydrophobic polymer composite base. The same is
gradually cooled to room temperature to obtain a dry powder base. The powder obtained is sifted
through sieve of 40 mesh to ensure the absence of lumps or agglomerates. The final composition
of the dry hydrophobic polymer composite base thus obtained is given in table 3
Table 3
Powder is sifted, reconstituted, sprayed on tablet as explained in example 1
Example 4 :
Process of preparation of hydrophobic polymer composite base comprises of heating 57.17%of
diethyl phthalate to 65degree Celsius and adding 9.74%of Glyceryl monostearate,
9.71%ofPolysorbate 80 and 23.38% of Stearic acid to form liquid dispersion.
Take 30% w/w of the above liquid dispersion (at a temperature 70-80°C) and mix with 70% w/w
poly vinyl alcohol to prepare the desired hydrophobic polymer composite base. The same is
gradually cooled to room temperature to obtain a dry powder base. The powder obtained is sifted
through sieve of 40 mesh to ensure the absence of lumps or agglomerates. The final composition
of the dry hydrophobic polymer composite base thus obtained is given in table 4
Table 4
Component Percentage in Hydrophobic polymer composite base
Glyceryl Monostearate 2.922
Polysorbate 80 2.913
Diethyl phthalate 17.151
Stearic Acid 7.014
Polyvinyl alcohol 70
Total 30
Powder is sifted, reconstituted, sprayed on tablet as explained in example 1
Example 5 :
The hydrophobic polymer composite base is taken from any of the preceding exampl
blended with other pharmaceutical ingredients.
Table 5
The powder composition is prepared using standard dry blending or mixing techniques known to
those of ordinary skill. The ingredients are individually weighed, added to high-speed mixer,
blended for a sufficient time until a substantially uniform mixture of the ingredients is obtained.
The time required to achieve such substantial uniformity will, of course, depend upon the batch
size. This mixture is then passed through a 40 mm sieve to ensure smoothness of the mixture. If
any of the powder formulation ingredients are liquids, they are added only after all of the dry
ingredients have been sufficiently blended, and the combination of wet and dry ingredients is
blended for an additional amount of time to ensure homogeneity once all of the liquid is
introduced.
The film coating can be applied as part of a pan coating or spray coating process commonly used
to coat such articles. The amount of coating applied will depend upon several factors, including
the nature and functionality of the film coating, the substrate to be coated and the apparatus
employed to apply the coating, etc.
In this case types of tablet used were medium sized, round, plane on both sides with sharp edges
with diameter 10mm, thickness 5mm and hardness of core 4.2 kg/cm sq.
Example 6:
The hydrophobic polymer composite base is taken from any of the preceding examples and
blended with other pharmaceutical ingredients.
Table 6
The powder mixtures are blended, sifted, reconstituted, sprayed on tablet as explained in
example 5.
Example 7:
The hydrophobic polymer composite base is taken from any of the preceding examples and
blended with other pharmaceutical ingredients.
Table 7
Ingredient Percentage by weight Weight in grams
Hydrophobic polymer 64% 640
composite base
Polyethylene 8% 80
Glycol/Triacetin
Magnesium Stearate 3% 30
Titanium Dioxide 24% 240
Pigment 1% 10
Total 100% 1000
The powder mixtures are blended, sifted, reconstituted, sprayed on tablet as explained in
example 5.
Example 8 :
The hydrophobic polymer composite base is taken from any of the preceding examples and
blended with other pharmaceutical ingredients.
Table 8
The powder mixtures are blended, sifted, reconstituted, sprayed on tablet as explained in
example 5.
Example 9
Process of preparation of hydrophobic polymer composite base comprises of heating 36.86%of
diethyl phthalate to 65degree Celsius and adding 7.96%of Glyceryl monostearate,
8.16%ofPolysorbate 80 and 47.02% of Stearic acid in order to form liquid dissolution so that the
total amount of all the ingredients in the blend will be 100 % by weight, heating the Mixture to
70-80 °C for 5- 10 min to get a homogenous dispersion.
Take 37% w/w of the above liquid dispersion (at a temperature 70-80°C) and mix with 63% w/w
poly vinyl alcohol to prepare the desired hydrophobic polymer composite base. The same is
gradually cooled to room temperature to obtain a dry powder base. The powder obtained is sifted
through sieve of 40 mesh to ensure the absence of lumps or agglomerates. The final composition
of the dry hydrophobic polymer composite base thus obtained is given in table 9
Table 9
The above composite base is used as a ready mix to be blended with color, lake colors, titanium
dioxide and Magnesium stearate to produce the desired product.
Table 10
The powder mixtures are prepared using standard dry blending or mixing techniques. The
ingredients are individually weighed, added to high speed mixer, blended for a sufficient time
until a substantially uniform mixture of the ingredients is obtained. The time required to achieve
such substantial uniformity will, of course, depend upon the batch size. This mixture is then
passed through a 40mm sieve to ensure smoothness of the mixture:
The film coating can be applied as part of a pan coating or spray coating process commonly used
to coat such articles. The amount of coating applied will depend upon several factors, including
the nature and functionality of the film coating, the substrate to be coated and the apparatus
employed to apply the coating, etc.
In this case types of tablet used were medium sized, round, plane on both sides with sharp edges
with diameter 10mm, thickness 5mm and hardness of core 4.2 kg/cm sq.
Ex ple
Process of preparation of Hydrophobic polymer composite base comprises heating of Diethyl
phthalate to 80 degree Celsius, Glyceryl monostearateand stearic acid in amounts as given in
table no 11. Heat the mixture to 70-80 °C for 5-10 min.
Table 11
When mixture obtained from above is taken in amounts of 33% w/w and mixed with 67%
w/wpolyvinyl alcoholit results in the formation of a powder. Powder thus obtained is redispersed
in water, however homogenous dispersion is not achieved.The properties expected to
result that were not comparable to those of earlier compositions suggesting that presence of each
component is necessary to obtain the desired properties.
Example 11
Preparation of the Aqueous Dispersion:
The inventive film coating composition as per above examples (20 grams) is dispersed into 80
grams of ambient temperature water to providean aqueous coating suspension having 20% w/w
non-water ingredients. The water is weighed into a vessel with a diameter approximately equal to
the depth of the final dispersion. A low shear mixer is lowered into the water and turned on to
create a vortex from the edge of the vessel down to just above the mixing blade to prevent
entrapment of air. The 20 grams of dry film coating composition is added to the vortex at a rate
where there is no excessive build-up of dry powder. The speed and depth of the mixing blade is
adjusted to avoid air being drawn into the suspension so as to avoid foaming. The suspension is
stirred at low speed (350 rpm or less) for 45 minutes to form a homogeneous aqueous dispersion
suitable for coating.
A kilogram batch of placebo tablets is spray coated with the aqueous dispersion described above
in fully perforated side-vented coaling i d wi h a pan insert having a diameter of 15
and one spray gun fitted with a nozzle having an aperture of 1 mm. The average coating
parameters were: Inlet air temperature 55-60 degree Celsius, tabletbed temperature 40-43 degree
Celsius, pump RPM 1 - 1.5 RPM, pan speed 35-38 RPM,atomizing air pressure 1.4-2.0 KG/cm
sq.
A non-limiting list of suitable substrates that can be coated with the inventive coating system
include compressed tablets, caplets, cores including pharmaceuticals, nutraceuticals and dietary
supplements as well as any other art-recognized orally ingestible core.
In this case types of tablets to be used is medium sized, round, plane on both sides with sharp
edges with diameter 10mm,thickness5mm and hardness of core 4-5 kg/cm sq.
MVTR (Moisture Vapour Transmission Rate) STUDIES for Example 1 Composition:
The films of Example 1 composition and other moisture barrier coating systems were prepared in
the desired solvent systems using clean glass plates and an applicator. These plates were dried in
oven at 40°C. Dried films were peeled from the plates with the help of surgical knife.
Pinhole free films of 100± l ( ere selected and placed at 30°C/65% R for 12 hours for
stabilization. MVTR studies was conducted using specially designed glass diffusion cells.This
assembly was placed in an oven at 40° C. Initial weight of the cell assembly was noted followed
by successive weight loss recordings at regular intervals for 24 hours.
A Blank assembly was also kept with an open mouth without any film.
MVTR value was calculated using the following formula
MVTR = G / t x a
a= Area of opening(exposed film): 2.833cm G = weight loss
t = time
Table 19
Moisture Barrier systems Time (MVTR Values)
12 hrs 24 hrs
Example 1 0.005806 0.005563
Example 2 0.006032 0.005771
Example 4 0.006413 0.006428
Example 9 0.005424 0.005222
HPMC based film 0.08702 0.08533
Control 0.31 0.34
We Claim:
1. An immediate release film coating composition comprising a dry hydrophobic polymer
composite base along with pharmaceutically acceptable excipients.
2. A dry hydrophobic polymer composite base as claimed in claim 1, comprising a polymer,
awaxy emulsifier, a plasticizer, a wetting agent and a hydrophobic agent.
3. An immediate release film coating composition as claimed in claim 1, comprising a
polymer, a waxy emulsifier, a plasticizer, a wetting agent, a hydrophobic agent and
optionally an opacifier, a pigment, a diluent, lubricant or other pharmaceutically
acceptable excipients.
4. The composition as claimed in claims 2 and 3, wherein the polymer is selected from the
group comprising polyvinyl alcohol (PVA), copolymers based on PVA,
polyvinylpyrrolidone-vinyl acetate copolymer (copovidone), polyvinylacetate phthalate,
methacrylic acid copolymers, hypromellose (hydroxypropylmethyl cellulose),
hydroxypropylcellulose, sodium carboxymethyl cellulose, ethyl cellulose.
5. The composition as claimed in claims 2 and 3, wherein the polymer is polyvinyl alcohol.
6. The composition as claimed in claims 2 and 3claims 2 and 3, wherein the polymer is in
the range of 55 to 80 %w/w, more preferably 60-75% w/w of the composition.
7. The composition as claimed in claims 2 and 3, wherein the plasticizer is selected from the
group comprising phthalate esters, phosphate esters, and other esters like citrates,
stearates, sebacate, oleate, oils, glycerols, glycols etc.
8. The composition as claimed in claims 2 and 3, wherein the plasticizer is selected from the
group comprising polyethylene glycol, ethyl phthalate, methyl phthalate, propylene
glycol, fractionated coconut oil, lecithin, castor oil, dibutylsebacate, diethyl phthalate,
dipropyl phthalate, dibutyl phthalate and combinations thereof, more preferably
dibutylsebacate, diethyl phthalate, dibutyl phthalate.
9. The composition as claimed in claims 2 and 3, wherein the plasticizer is in the range of
10 to 25% w/w, preferably 10-20% w/w of the composition
10. The composition as claimed in claims 2 and 3, wherein the waxy emulsifier is selected
from the group comprising glyceryl monostearate, glycerylbehenate,
glycerylpalmitostearate, sorbitan ester, palmitic acid, polyoxyethylene alkyl ether,
lauroylpolyoxylglyceride and stearoylpolyoxylglyceride, ceresin, cetostearyl alcohol,
cetyl alcohol, docusate sodium, ethyl maltol, ethylene glycol stearates,
glycerylmonooleate, lanolin, myristic acid, petrolatum/lanolin alcohol, polyoxyl 6
stearate, polyoxyl 8 stearate, propylene glycol monostearate, sorbitan tristearate, sodium
stearylfumarate, stearyl alcohol, hydrogenated vegetable oil, carnauba wax,
microcrystalline wax and zinc stearate.
11. The composition as claimed in claims 2 and 3, wherein the waxy emulsifier is in the
range of 0.3 % w/w to 10 % w/w, more preferably in the range of 0.5. % w/w to 6% w/w.
12. The composition as claimed in claims 2 and 3, wherein the wetting agent is selected from
the group comprising Tween 20 (polysorbate 20 or poloxyethylene (20) sorbitan
monolaurate), Tween 40 (polysorbate 40 or polyoxyethylene (20) sorbitan
monopalmitate), Tween 60 (polysorbate 60 or polyoxyethylene (20) sorbitan
monostearate), Tween 80 (polysorbate 80 or polyoxyethylene (20) sorbitan monoleate),
sodium lauryl sulphate and combinations thereof, preferably the wetting agent is
polysorbate 80
13. The composition as claimed in claims 2 and 3, wherein the wetting agent is in the range
of 0.3% w/w to 10% w/w, preferably in the range of 0.5% w/w to 5% w/w.
14. The composition as claimed in claims 2 and 3, wherein the hydrophobic agent is selected
from a group comprising stearic acid, sodium stearate, calcium stearate, zinc stearate,
glyceryl palmitostearate.
15. The composition as claimed in claims 2 and 3, wherein the hydrophobic agent is in the
range of 1% w/w to 25% w/w, preferably in the range of 5% w/w to 20% w/w.
16. The composition as claimed in claims 2 and 3, optionally comprising other ingredients
such as, a colorant, an opacifier, a diluent, a lubricant, a pigment, a flavoring agent or a
sweetening agent.
17. The composition as claimed in claims 16, wherein the opacifier is selected from the
group comprising titanium dioxide, zinc oxide, calcium carbonate, magnesium oxide.
18. The composition as claimed in claims 16, wherein the opacifier is in the range of 0.1 %
w/w to 25% w/w.
19. The composition as claimed in claim 16 , wherein the pigment is selected from the group
comprising, iron oxide colors, Lake or soluble colors, natural colors, candurin colors and
the like.
20. The composition as claimed in claim 16, wherein the diluent is selected from the group
comprising calcium carbonate, calcium phosphate, magnesium trisilicate, tri basic
calcium phosphate, micro-crystalline cellulose and the like.
21. The composition as claimed in claim 16, wherein the diluent is selected from the group
comprising magnesium stearate, calcium stearate, zinc stearate, stearic acid, mineral oil,
and combinations thereof.
22. The composition as claimed in claim 16, wherein the flavoring agent is selected from the
group comprisingpowder, liquid, encapsulated flavors either natural or syntheticorigin.
23. The composition as claimed in claim 16, wherein the sweetener is selected from the
group comprising glucose, fructose, sorbitol, aspartame, glycerol, saccharin, xylitol.
24. A composition as claimed in claim 16, wherein the dry hydrophobic polymer composite
base present is the range of 40 to 90%, preferably in the range of 45 % w/w to 80%,
along with an opacifier in the range of 0.1-25% w/w, a pigment in the range of 0.1-25%
w/w, a diluent in the range of 0.1-15% w/w, a lubricant in the range of 1-15% w/w or
combinations thereof along with other pharmaceutically acceptable excipients.
25. A process for preparing the composition as claimed in claims 2 and 3 comprising the
steps of:
1. combining the liquefied plasticizer with the waxy emulsifier, hydrophobic agent
and wetting agent;
2. heating the above said mixture to obtain a homogenous liquid dispersion;
3. adding the polymer to the heated mixture of step 1 to obtain the hydrophobic
polymer composite base in dry powder form;
4. optionally adding other pharmaceutical excipients to obtain the composition of the
present invention.
26. The composition as claimed in claims 2 and 3, when reconstituted in a solvent selected
from the group comprising aqueous solutions, water, de-mineralized water, preferably
purified water,having solid content in the range of 10-40% w/w, preferably 15 to 30%
w/w of solvent.
27. The composition as claimed in claim 26, comprising solid content of 15% to 30% by
weight in the suspension on reconstitution.
28. A method of coating a substrate with the composition of claims 2 and 3, wherein the
substrate is selected from the group comprising pharmaceutical materials, nutritional
supplements, food, confectionery forms, agricultural seeds.
29. An orally ingestible substrate coated with the dry film coating composition of claims 2
and 3.
30. A dry film coating composition and method of coating as described in the specification
with reference to forgoing examples.