MULTILAYERED DOSAGE FORM
Field of the Invention
The present invention relates to a multilayered coated tablet comprising at least
three layers, i.e., first, second and third layer wherein the first and third layers contain at
least one active pharmaceutical ingredient and the second layer is either a placebo or an
immediate-release drug layer. Further, the tablet has a delayed-release coating, wherein
the coating may contain one or more pore-forming agents and/or orifices on one or both
sides. Furthermore, it may contain an immediate-release layer of the drug over the
delayed-release coating layer. The present invention further relates to processes for
preparing such a multilayered coated tablet.
Background of the Invention
Oral drug delivery continues to be the most popular route of administration due to
its versatility, ease of administration and patient compliance. An oral medication that
improves compliance, and thus results in more effective treatment, has been one of the
major drivers of innovation in the oral drug delivery market.
Modified-release or a controlled-release dosage form is an advancement in the oral
drug delivery which has led to improved patient compliance and reduced side effects of
the drugs. "Modified-release" means that the release of the drug from the dosage form has
been modified in some way with respect to an immediate-release delivery of the same
drug. Usually, this is to slow the release of the drug so that the medicine doesn't have to
be taken too often and therefore improves compliance. The other benefit from modifyingrelease
is that the drug release is controlled and there are smaller peaks and troughs in
blood levels, therefore reducing the chance of peak effects and increasing the likelihood of
therapeutic effectiveness for longer periods of time.
Generally, controlled-release systems can be categorized into two groups based on
actions. Extended-release formulations deliver a portion of the total dose shortly after
ingestion and the remainder over an extended time frame. Delayed-release systems
provide steady dosing after passage through the stomach. Controlled-drug delivery
systems aim to maintain plasma concentration of drugs within the therapeutic window for
a longer period of time, thereby to ensure sustained therapeutic action.
Further manipulation of delivery systems has led to the development of
chronotherapeutic systems, where release enables a drug to take advantage of the natural
biorhythms of the human body. Pulsatile drug delivery system provides a
chronotherapeutic release to meet the needs of patients suffering from diseases which
follow the biological rhythm, such as asthma, where episodes of attack mostly happen late
at night or rheumatoid arthritis, where the pain peaks at the morning. Pulsatile drug
delivery systems are characterized by at least two distinctive drug-release phases
following a predetermined lag time. Drug's release may be controlled by time, by site or a
combination of the two parameters.
Two of the most widely commercialized controlled-release technologies are Oros®
(developed by Alza), and the Sodas® technology developed by Elan. Other successfully
commercialized technologies include SkyePharma's Geomatrix®, Eurand's Diffucaps®
and Elan's Codas®.
U.S. Patent Nos. 5,318,558 and 5,221,278, assigned to Alza, claim the pulsatile
delivery of agents from osmotic systems based on the technology of an expandable orifice.
U.S. Patent No. 7,387,793, assigned to Eurand, relates to a multi-particulate
pharmaceutical dosage form wherein the active drug is layered onto a neutral core (such as
cellulose spheres) and then one or more rate-controlling, functional membranes are
applied.
U.S. Patent No. 6,797,283, assigned to Alza, relates to a multilayered dosage form
comprising: a first layer comprising an amount of swellable polymer, said amount being
sufficient to swell said first layer such that the active agent dosage form is retained within
a stomach of a subject; a second layer laminated with the first layer at a common surface,
said second layer comprising a therapeutic amount of an active agent and being formulated
to swell to a lesser extent than the first layer; and at least one band of insoluble material
circumscribing only a portion of said first layer and said second layer, said at least one
band of insoluble material binding together the first layer and the second layer.
U.S. Patent No. 6,183,778, assigned to Jagotec AG, relates to an oral dosage form
in the form of a tablet, capable of providing one or more pharmaceutically active
substances in two or more different releases, the dosage form comprising at least three
layers of specific geometric shape, wherein the dosage form comprises:
a) a first layer from which there occurs a first release of at least one
pharmaceutically active substance, wherein the release is characterized as an
immediate-release or a controlled-release, the layer comprising substances which
swell or solubilize when contacted with aqueous liquids;
b) a second layer from which there occurs a second release of at least one
pharmaceutically active substance, wherein the at least one pharmaceutically active
substance is the same as or different from the at least one pharmaceutically active
substance released from the first layer in the first release, wherein the second
release is characterized as a controlled-release, the second layer comprising
substances that swell, or erode, or are gellable when contacted with aqueous
liquids; and
c) a third layer at least partially coating one or more free surfaces of the second
layer, the third layer comprising substances that swell, or erode, or are gellable
when contacted with aqueous liquids, and wherein at least two layers of the dosage
form are formed by the compression of a mixture of granular components.
U.S. Patent No. 5,783,212, assigned to Temple University of the Commonwealth
System of Higher Education, discloses a multilayer tablet for release of active
pharmaceutical ingredient at a constant rate with a zero order kinetic profile, in which two
outer layers contain swellable and erodible polymers, an inner layer contains an active
pharmaceutical ingredient and swellable and erodible polymers, and each layer differs in
composition and thickness.
U.S. Patent No. 5,626,874, assigned to Ekita Investments N.V., discloses a
multilayer tablet consisting of two outer layers containing gellable or erodible polymers
and an inner layer containing an active ingredient. The side surface of the inner layer
occupies about 5% to 35% of the tablet's total surface.
U.S. Publication No. 2010/0040681, filed by GL Pharmtech Corp., relates to an
oral sustained-release triple layer tablet, more particularly, a triple layer tablet consisting
of an inner immediate-release layer containing an active pharmaceutical ingredient and
two outer layers containing swellable polymers. On exposure to aqueous media, the two
outer layers swell to form gelled layers surrounding the lateral side of the inner layer
rapidly, thereby controlling effectively the release of drug from the inner immediaterelease
layer.
U.S. Patent No. 5,549,913, assigned to Inverni Delia Beffa S.p.A., discloses a
multilayer tablet for release of active pharmaceutical ingredient at a constant rate with a
zero order kinetic profile, in which two outer layers contain active pharmaceutical
ingredient and hydrophilic polymers, and an inner layer contains a water-soluble polymer
without the active pharmaceutical ingredient. The inner layer is readily dissolved in
aqueous media to separate the two outer layers, and thus to increase the surface area of the
matrix.
The present -inventors h e developed a novel multilayered coated tablet
comprising at least three layers, wherein the first and third layers contain at least one
active pharmaceutical ingredient and the second layer is either a placebo or an immediaterelease
drug layer. This tablet further comprises a delayed-release coating wherein the
coating may contain one or more pore-forming agents and/or orifices on one or both sides.
Further, there may be an immediate-release layer over the delayed-release coating for an
initial pulse. The orifice or pore-forming agents present in the coating lead to an initial
hydration and slow-release of the drug until the time it reaches the intestine. After
reaching the intestine, the delayed-release coating and the second placebo or drug layer
dissolve or erode separating the first and third drug layers. The first and third drug layers
of the dosage form can be two extended-release layers or one immediate-release layer and
another extended-release layer. The present dosage form also provides the pulsatilerelease
of the drug by the delivery of the drug from two or three different layers with
different release rates. Further, the present dosage form can be used to formulate two
incompatible drugs into a single tablet, wherein the second layer will prevent the two
drugs from coming in contact with each other.
Summary of the Invention
The present invention relates to a multilayered coated tablet.
One aspect of the present invention relates to a multilayered coated tablet,
comprising at least three layers wherein:
a) the first and third layers contain an active pharmaceutical ingredient; and
b) the second layer is either a placebo layer or contains active pharmaceutical
ingredient.
According to one of the embodiments of the present invention, the first and third
layers contain the same drug.
According to another embodiment of the present invention, the first and third
layers contain different drugs.
According to another embodiment of the present invention, at least one of the first
and third layers provides an extended-release of drug.
According to yet another embodiment of the present invention, the first layer
provides an immediate-release of the drug and the third layer provides an extended-release
of the drug.
According to yet another embodiment of the present invention, the first layer
provides an extended-release of the drug and the third layer provides an immediate-release
of the drug.
According to another embodiment of the present invention, the second layer is a
placebo layer.
According to yet another embodiment of the present invention, the second layer is
water-soluble or water-swellable or water-insoluble and helps in the division of the tablet
into different layers.
According to another embodiment of the present invention, the second layer
comprises microcrystalline cellulose, corn starch, povidone, magnesium stearate, talc or
lactose and optionally a drug.
According to yet another embodiment of the present invention, the second layer
comprises an immediate-release drug layer.
According to another embodiment of the present invention, the three layers contain
the same drug.
According to another embodiment of the present invention, the three layers contain
different drugs.
According to another embodiment of the present invention, two of the layers
contain the same drug and the third layer contains a different drug.
According to another embodiment of the present invention, the coating on the said
multilayered tablet is a delayed-release coating.
According to another embodiment of the present invention, the delayed-release
coating contains an orifice on one side of the tablet.
According to another embodiment of the present invention, the delayed-release
coating contains an orifice on both sides of the tablet.
According to another embodiment of the present invention, the delayed-release
coating contains at least one pore-forming agent.
According to another embodiment of the present invention, the delayed-release
coating contains an orifice on one side of the tablet and a pore-forming agent.
According to another embodiment of the present invention, the delayed-release
coating contains an orifice on both sides of the tablet and a pore-forming agent.
According to another embodiment of the present invention, the pore-forming agent
used in the delayed-release coating is selected from hydrophilic, hydrophobic, or a
combination of both hydrophilic and hydrophobic substances such as sodium chloride,
potassium chloride, and magnesium salts, lactose, sucrose, sorbitol, and mannitol,
polyvinyl alcohols and glycols, such as polyethylene glycol and propylene glycol;
hydroxypropyl celluloses, hydroxy propyl methycelluloses; methacrylic acid copolymers;
croscarmellose sodium, crospovidone sodium starch glycolate, talc, silicon dioxide,
polyvinylpyrrolidones, gelling agents such as carbopol, xanthan gum; or mixtures thereof.
According to another embodiment of the present invention, the delayed-release
polymer used in the delayed-release coating is selected from cellulose acetate phthalate
(CAP), cellulose acetate trimelletate (CAT), polyvinyl acetate)phthalate (PVAP),
hydroxypropyl methylcellulose phthalate (HPMCP), poly(methacrylate ethylacrylate)
(1:1) copolymer (MA-EA), poly(methacrylate methylmethacrylate) (1:1) copolymer (MA
MMA), poly(methacrylate methylmethacrylate) (1:2) copolymer, (Eudragit®-L-30-D,
Eudragit®L 100-55), Eudragit® LI00, Eudragit® LI2,5, Eudragit® SI00, Eudragit®
S12,5), Poly(methyl acrylate-co-methyl methacrylate-co-methacrylic acid) 7:3:1 -
(Eudragit® FS30D) hydroxypropyl methylcellulose acetate succinate (HPMCAS), and
combinations thereof.
According to another embodiment of the present invention, the delayed-release
coating further comprises an immediate-release drug layer over it.
According to another embodiment of the present invention, the immediate-release
drug layer over the delayed-release coating layer may contain the same drug as those in
any of the internal layers of the tablet.
According to another embodiment of the present invention, the immediate-release
layer over the delayed-release coating layer may contain a drug different than those in any
of the internal layers of the tablet.
According to another embodiment of the present invention, the shape of the tablet
is capsular, circular or cylindrical.
According to another aspect of the present invention, the multilayered coated tablet
of the present invention further comprises pharmaceutically acceptable excipients selected
from the group comprising adsorbents, antioxidants, acidifying agents, alkalizing agents,
buffering agents, colorants, flavorants, sweetening agents, antiadherents, binders, diluents,
direct compression excipients, disintegrants, glidants, lubricants opaquants and/or
polishing agents.
According to another aspect of the present invention, the multilayered coated tablet
of the present invention is prepared by blending or dry granulating or wet granulating
pharmaceutically active agent of the first and the third layers with one or more excipients
and blending inert excipients of the second layer and finally compressing the three blends
into a tri-layered tablet, which is further coated using the coating dispersion of the
delayed-release polymer. And by further drilling an orifice on one or both the sides of the
tablet.
According to another aspect of the present invention, the multilayered coated tablet
of the present invention is prepared by blending or dry granulating or wet granulating
pharmaceutically active agent of the first, second and the third layers with one or more
excipients and finally compressing the three blends into a tri-layered tablet, coating using
the coating dispersion of the delayed-release polymer, further drilling an orifice on one or
both the sides of the tablet and finally layering an immediate-release drug layer over the
delayed-release coating.
Detailed Description of the Invention
The present invention relates to a novel multilayered coated tablet having at least
three layers, i.e., first, second and third layer.
The phrase "multilayered coated tablet", as used herein, relates to a tablet having
more than two layers. More particularly, it relates to a tablet having three layers.
The phrase "active pharmaceutical ingredient", as used herein, relates to any
therapeutic or diagnostic agent now known or hereinafter discovered that can be
formulated as described herein.
The active pharmaceutical ingredient may be selected from the group consisting of
pharmaceutically acceptable organic or inorganic compounds including analgesics,
anticonvulsants, anesthetics, antidiabetic agents, anti-infective agents, antineoplastics,
antiparkinsonian agents, antirheumatic agents, cardiovascular agents, central nervous
system stimulants, dopamine receptor agonists, gastrointestinal agents, psychotherapeutic
agents, or urinary tract agents.
Suitable examples of drugs which can be incorporated into the dosage form of the
present invention include, but are not limited to, albuterol sulfate, amoxicillin, bupropion
hydrochloride, carbidopa, cefaclor, diclofenac sodium, erythromycin, felodipine,
loratidine, lithium carbonate, methylphenidate, metaprolol tartrate, nifedipine, propranolol,
verapamil hydrochloride, omeprazole, sotalol hydrochloride, theophylline, terbutaline
sulphate, enalapril, diltiazem, nifedipine, lovastatin, simvastatin, ibuprofen, indomethacin,
tenoxicam, and acetylsalicylic acid.
The term "pharmaceutically acceptable excipient" is intended to denote any
material which is inert in the sense that it substantially does not have any therapeutic
and/or prophylactic effect per se. Such an excipient may be added with the purpose of
making it possible to obtain a pharmaceutical composition which has acceptable technical
properties.
As used herein, the term "alkalizing agent" is intended to mean a compound used
to provide alkaline medium for product stability.
As used herein, the term "acidifying agent" is intended to mean a compound used
to provide an acidic medium for product stability.
The multilayered coaied tablet of the present invention comprises at least three
layers; first, second and third layer; wherein the said first and third layers are drug layers
and second layer is either a placebo or an immediate-release drug layer. This tablet further
comprises a delayed-release coating wherein the coating may contain one or more poreforming
agents and/or orifices on one or both sides. Further, there may be an immediaterelease
layer over the delayed-release coating for an initial pulse. The orifice or poreforming
agents present in the coating lead to an initial hydration and slow-release of the
drug until the time it reaches the intestine. The incorporation of the pore-forming agents
or the orifices in the polymer coating allows for a release of the medicament in the
stomach for immediate-release and thereafter release additional medicament in the
intestines for delayed-release. After reaching the intestine, the delayed-release coating and
the second placebo or drug layer dissolves or erodes, separating the first and third drug
layers.
The two drug layers of the dosage form can be two extended-release layers or one
immediate-release layer and another extended-release layer. The present dosage form also
provides for the pulsatile-release of the drug by the delivery of the drug from two different
layers with different release rates. Further, the present dosage form can be used to
formulate two incompatible drugs into a single tablet wherein the second layer will
prevent the two drugs from coming in contact with each other.
The multilayered coated tablet of the present invention further comprises
pharmaceutically acceptable excipients selected from the group comprising binders,
diluents, direct compression excipients, disintegrants, glidants, lubricants, antioxidants,
acidifying agents, alkalizing agents, colorants, flavorants, sweetening agents,
antiadherents, and plasticizers.
Suitable examples of binders include, but are not limited to, polyvinylpyrrolidone,
starch mucilage, pregelatinized starch, sodium alginate, alginic acid, acacia mucilage,
tragacanth, hydroxypropylmethyl cellulose, carboxymethylcellulose sodium,
carboxymethylcellulose calcium, microcrystalline cellulose, ethyl cellulose, polyethylene
glycol, hydroxyethyl cellulose, hydroxy propyl cellulose, methyl cellulose,
polymethacrylates, carboxyvinyl polymers, carbopols, and combinations thereof.
Suitable examples of diluents include, but are not limited to, corn starch, lactose,
white sugar, sucrose, sugar compressible, sugar confectioners, glucose, sorbitol, calcium
carbonate, calcium phosphate-dibasic, calcium phosphate-tribasic, calcium sulfate,
microcrystalline cellulose, silicified microcrystalline cellulose, cellulose powdered,
dextrates, dextrins, dextrose, fructose, kaolin, lactitol, mannitol, starch, pregelatinized
starch, or mixtures thereof.
Suitable examples of disintegrants include, but are not limited to, cross-linked
polyvinylpyrrolidone, sodium starch glycolate, cross-linked sodium carboxymethyl
cellulose (crosscarmellose sodium), calcium carboxymethyl cellulose, alginic acid and
alginates, pregelatinised starch, starch and starch derivatives, low-substituted
hydroxypropyl cellulose, and combinations thereof.
Examples of lubricants and glidants include, but are not limited to, colloidal
anhydrous silica, stearic acid, magnesium stearate, calcium stearate, talc, hydrogenated
castor oil, sucrose esters of fatty acids, microcrystalline wax, yellow beeswax, white
beeswax, or mixtures thereof.
Suitable examples of direct compression excipients include, but are not limited to,
dibasic calcium phosphate, microcrystalline cellulose, lactose, mannitol, or mixtures
thereof.
Examples of antioxidants include, but are not limited to, ascorbic acid, ascorbyl
palmitate, butylated hydroxyanisole, butylated hydroxytoluene, hypophosphorous acid,
monothioglycerol, propyl gallate, sodium ascorbate, sodium bisulfite, sodium
formaldehyde sulfoxylate and sodium metabisulfite, or mixtures thereof.
Suitable examples of alkalizing agents include, but are not limited to, ammonia
solution, ammonium carbonate, diethanolamine, monoethanolamine, potassium hydroxide,
sodium borate, sodium carbonate, sodium bicarbonate, sodium hydroxide, triethanolamine,
diethanolamine, organic amine base, alkaline amino acids and trolamine.
Suitable examples of acidifying agents include, but are not limited to, acetic acid,
acidic amino acids, citric acid, fumaric acid and other alpha hydroxy acids, hydrochloric
acid, ascorbic acid, phosphoric acid, sulfuric acid, tartaric acid and nitric acid.
Examples of plasticizers include triethyl citrate, tributyl citrate, triacetin,
polyethylene glycol, propylene glycol, diethylphthatate and oils/glycerides such as
fractionated coconut oil or castor oil, and any combination thereof.
Coloring agents and flavoring agents may be selected from any FDA approved
colors and flavors for oral use.
The pharmaceutical compositions of the present invention may optionally contain
surfactants.
Surfactants/wetting agents include both non-ionic and ionic (cationic, anionic and
zwitterionic) surfactants suitable for use in pharmaceutical compositions. These include
but are not limited to, polyethoxylated fatty acid esters, polyethylene glycol fatty acid
esters, alcohol-oil transesterification products, polyglycerized fatty acids, polyethylene
glycol sorbitan fatty acid esters, sugar esters, polyoxyethylene-polyoxypropylene block
copolymers, ionic surfactants, derivatives of fat-soluble vitamins, and mixtures thereof.
Suitable examples include sodium lauryl sulphate, sodium dodecyl sulphate,
polyoxyethylene castor oil derivatives, for example, tweens, polyoxyethylenepolyoxypropylene
block copolymers, for example, poloxamer, or mixtures thereof.
Suitable extended-release polymers may be selected from one or more of watermiscible
polymers, water-insoluble polymers, oils and oily materials, and mixtures
thereof.
The water-miscible polymer may be selected from one or more of hydroxypropyl
methylcellulose, hydroxypropyl cellulose, methylcellulose, sodium
carboxymethylcellulose, hydroxyethyl cellulose and other cellulose derivatives,
polymethacrylic copolymer, poloxamers, polyoxyethylene stearate, polyvinylpyrrolidone,
polyvinylpyrrolidone-polyvinylacetate copolymer (PVP-PVA), polyvinyl alcohol,
polyethylene oxide, and mixtures thereof.
The water-insoluble polymer may be selected from one or more of ethyl cellulose,
cellulose acetate, cellulose nitrate, and mixtures thereof.
The oil or oily material may be hydrophilic or hydrophobic oil or oily material or
their mixtures. Hydrophilic oil or oily material may be polyether glycols such as
polypropylene glycols; polyoxyethylenes; polyoxypropylenes; poloxamers; polyglycolized
glycerides such as gelucire and mixtures thereof. Hydrophobic oil or oily material may be
straight chain saturated hydrocarbons; sorbitan esters such as sorbitan di isostearate,
sorbitan dioleate, sorbitan monolaurate, sorbitan monoisostearate, sorbitan monooleate,
sorbitan monopalmitate, sorbitan monostearate, sorbitan sesqui-isostearate, sorbitan
sesquioleate, sorbitan sesquistearate, sorbitan tri-isostearate, sorbitan trioleate, sorbitan
tristearate; higher fatty acid such as stearic acid, myristic acid, palmitic acid; higher
alcohols such as cetanol, stearyl alcohol; waxes such as glyceryl monostearate, glyceryl
monooleate, hydrogenated tallow, myristyl alcohol, stearyl alcohol, yellow beeswax, white
beeswax, carnauba wax, castor wax, Japan wax; substituted and/or unsubstituted mono, di
or triglycerides; NVP polymers; PVP polymers; acrylic polymers, and mixtures thereof.
Delayed-release material (coating) used in the multi-layered tablet of the invention
will possess limited solubility or erodibility or be insoluble or non-erodible in a first
external fluid, i.e., gastric juices, while being soluble and/or erodible in a second external
fluid, such as intestinal juices.
Suitable examples of such polymeric materials include, but are not limited to,
cellulose acetate phthalate (CAP), cellulose acetate trimelletate (CAT), poly(vinyl
acetate)phthalate (PVAP), hydroxypropyl methylcellulose phthalate (HPMCP),
poly(methacrylate ethylacrylate) (1:1) copolymer (MA-EA), poly(methacrylate
methylmethacrylate) (1:1) copolymer (MA-MMA), poly(methacrylate
methylmethacrylate) (1:2) copolymer, Eudragit®L-30-D (MA-EA, 1:1), Eudragit® L-100-
55 (MA-EA, 1:1), Eudragit® L100, Eudragit® L12,5, Eudragit® S100, Eudragit® S12,5,
Poly(methyl acrylate-co-methyl methacrylate-co-methacrylic acid) 7:3:1 - (Eudragit®
FS30D) hydroxypropyl methylcellulose acetate succinate, Coateric®(PVAP),
Aquateric®(CAP), Aqoat®(HPMCAS), and combinations thereof.
The pore-forming agent used in the delayed-release coating is selected from
hydrophilic, hydrophobic, or a combination of both hydrophilic and hydrophobic,
substances such as sodium chloride, potassium chloride, and magnesium salts, lactose,
sucrose, sorbitol, and mannitol, polyvinyl alcohols and glycols, such as polyethylene
glycol and propylene glycol; hydroxypropyl celluloses, hydroxy propyl methycelluloses;
methacrylic acid copolymers; croscarmellose sodium, crospovidone sodium starch
glycolate, talc, silicon dioxide, polyvinylpyrrolidones, gelling agents such as carbopol, and
xanthan gum; and any mixtures thereof.
An orifice was drilled in the coating using laser drilling either on one side of the
tablet or on both sides.
The blend for multilayered tablet of the present invention is prepared by dry
mixing or dry granulation or wet granulation or any other process known in the art.
Finally compressing the three blends into a tri-layered tablet, which is further coated using
the coating dispersion of the delayed-release polymer. Then drilling an orifice on one or
both sides of the tablet. Further, the delayed-release coating may be layered with an
optional immediate-release drug layer.
The following examples represent various embodiments according to the present
invention. The examples are given solely for the purpose of illustration and are not to be
construed as liming the present invention in any way, as many other variations thereof are
possible within the scope of the invention.
Example 1
Process
First layer:
1. Sieve diltiazem HC1, hydroxypropylmethylcellulose and lactose and then blend
them together.
2. Then pass talc and magnesium stearate through sieve and transfer the mixture to
the blender of step 1.
Second layer:
1. Sieve lactose, talc and magnesium stearate and then blend them together.
Third layer:
1. Sieve diltiazem HC1, hydroxypropylmethylcellulose and lactose and blend them
with each other.
2. Then pass talc and magnesium stearate through sieve and transfer the mixture to
the blender of step 1.
Finally, compress all three layers into a tablet.
Coating:
1. Disperse talc in purified water.
2. Add triethyl citrate to the mixture of step 1.
3. Further add Eudragit® L30D-55 to the above dispersion while stirring slowly.
4. Coat the compressed tablets using the coating dispersion of step 3.
5. Finally, drill the orifice on one of the sides of the coated tablet.
Example 2
Process
First layer:
1. Sieve diltiazem HCl, carbopol and lactose and blend them together.
2. Then pass talc and magnesium stearate through sieve and transfer the mixture to
the blender of step 1.
Second layer:
1. Sieve lactose, talc and magnesium stearate and then blend them together.
Third layer:
1. Sieve diltiazem, HCl, hydroxypropylmethylcellulose and lactose and blend them
with each other.
2. Then pass talc and magnesium stearate through sieve and transfer the mixture to
the blender of step 1.
Finally, compress all three layers into a tablet.
Coating:
1. Disperse talc in purified water.
2. Add polyvinylpyrrolidone and triethyl citrate to the mixture of step 1.
3. Further add Eudragit® L30D-55 to the above dispersion while stirring slowly.
4. Then coat compressed tablets using the coating dispersion of step 3.
Example 3
Process
First layer:
1. Sieve propranolol HCl, hydroxypropylmethylcellulose and lactose and blend them
together.
2. Then pass talc and magnesium stearate through sieve and transfer the mixture to
the blender of step 1.
Second layer:
1. Sieve lactose, talc and magnesium stearate and then blend them together.
Third layer:
1. Sift propranolol HCl, hydroxypropylmethylcellulose and lactose and blend them
with each other.
2. Then pass talc and magnesium stearate through sieve and transfer the mixture to
the blender of step 1.
Finally, compress all three layers into a tablet.
Coating:
1. Disperse talc in purified water.
2. Add triethyl citrate to the mixture of step 1.
3. Further add Eudragit® L30D-55 to the above dispersion while stirring slowly.
4. Then coat compressed tablets using the coating dispersion of step 3.
5. Finally, drill the orifice on both sides of the coated tablet.
Example 4
Process
First layer:
1. Sieve propranolol HC1, hydroxypropylmethylcellulose and lactose and blend them
together.
2. Then pass talc and magnesium stearate through sieve and transfer the mixture to
the blender of step 1.
Second layer:
1. Sieve lactose, talc and magnesium stearate and then blend them together.
Third layer:
1. Sieve propranolol HCl, hydroxypropylmethylcellulose and lactose and blend them
with each other.
2. Then pass talc and magnesium stearate through sieve and transfer the mixture to
the blender of step 1.
Finally, compress all three layers into a tablet.
Coating:
1. Disperse talc in purified water.
2. Add polyvinylpyrrolidone and triethyl citrate to the mixture of step 1.
3. Further add Eudragit® L30D-55 to the above dispersion while stirring slowly.
4. Then coat the compressed tablets using the coating dispersion of step 3.
Example 5
Process
First layer:
1. Sieve propranolol HCl, hydroxypropylmethylcellulose and lactose and blend them
together.
2. Then pass talc and magnesium stearate through sieve and transfer the mixture to
the blender of step 1.
Second layer:
1. Sieve lactose, talc and magnesium stearate and then blend them together.
Third layer:
1. Sift propranolol HCl, hydroxypropylmethylcellulose and lactose and blend them
with each other.
2. Then pass talc and magnesium stearate through sieve and transfer the mixture to
the blender of step 1.
Finally, compress all three layers into a tablet.
Coating:
1. Disperse talc in purified water.
2. Add polyvinylpyrrolidone and triethyl citrate to the mixture of step 1.
3. Further add Eudragit® L30D-55 to the above dispersion while stirring slowly.
4. Then coat the compressed tablets using the coating dispersion of step 3.
Drug layering process:
1. Disperse propranolol HCl in aqueous/non-aqueous vehicle.
2. Add hydroxypropylmethylcellulose to the mixture of step 1.
3. Then coat the delayed-release tablets using the coating dispersion of step 2.
Example 6
Process
First layer:
1. Pass fexofenadine, hydroxypropylmethylcellulose and lactose through a sieve and
blend them together.
2. Pass talc through a sieve and transfer to the blender of step 1.
Second layer:
1. Pass lactose through a sieve.
Third layer:
1. Pass pseudoephedrine HC1, hydroxypropylmethylcellulose and lactose through a
sieve and then blend them together.
2. Then pass talc through a sieve and transfer to the blender of step 1.
Finally, compress all three layers into a tablet.
Coating:
1. Disperse talc in purified water.
2. Add triethyl citrate to the mixture of step 1.
3. Further add Eudragit® L30D-55 to the above dispersion while stirring slowly.
4. Then coat the compressed tablets using the coating dispersion of step 3.
5. Finally, drill the orifice on one of the sides of the coated tablet.
Example 7
Process
First layer:
1. Diltiazem HCl, hydroxypropylmethylcellulose and lactose were passed through a
sieve and then blended together.
2. Then ferric oxide red and talc were passed through a sieve and were transferred to
the blender of step 1.
Second layer:
1. Lactose was passed through a sieve.
Third layer:
1. Diltiazem HC1, hydroxypropylmethylcellulose and lactose were passed through a
sieve and then blended together.
2. Then ferric oxide yellow and talc were passed through a sieve and was transferred
to the blender of step 1.
Finally, all three layers were compressed into a tablet.
Coating:
1. Talc was dispersed in purified water.
2. Then povidone was added to the talc suspension of step 1.
3. Triethyl citrate was added to the mixture of step 2.
4. Further Eudragit® L30D-55 was added to the above dispersion while stirring
slowly.
5. The compressed tablets were coated using the coating dispersion of step 4.
6. Finally, an orifice was drilled on one of the sides of the coated tablet.
Example 8
Process
First layer:
1. Simvastatin, hydroxypropylmethylcellulose and lactose were passed through a
sieve and then blended together.
2. Then ferric oxide red and talc were passed through a sieve and were transferred to
the blender of step 1.
Second layer:
1. Lactose and povidone were passed through a sieve and blended together.
Third layer:
1. Niacin, hydroxypropylmethylcellulose and lactose were passed through a sieve and
then blended together.
2. Then ferric oxide yellow and talc were passed through a sieve and were transferred
to the blender of step 1.
Finally, all three layers were compressed into a tablet.
Coating:
1. Talc was dispersed in purified water.
2. Triethyl citrate was added to the mixture of step 1.
3. Further Eudragit® L30D-55 was added to the above dispersion while stirring
slowly.
4. The compressed tablets were coated using the coating dispersion of step 3.
5. Finally, an orifice was drilled on both sides of the coated tablet.

Claims:
1. A multilayered coated tablet, comprising at least three layers wherein:
a) the first and the third layer contain at least one active pharmaceutical
ingredient; and
b) the second layer is either a placebo layer or contains active pharmaceutical
ingredient.
2. The multilayered coated tablet according to claim 1, wherein the first and third layers
contain the same drug.
3. The multilayered coated tablet according to claim 1, wherein the first and third layers
contain different drugs.
4. The multilayered coated tablet according to claim 1, wherein the first and third layers
provide an extended-release of the drug contained therein.
5. The multilayered coated tablet according to claim 1, wherein the first layer provides
an immediate-release of the drug and the third layer provides an extended-release of the
drug contained therein.
6. The multilayered coated tablet according to claim 1, wherein the first layer provides
an extended-release of the drug and the third layer provides an immediate-release of the
drug contained therein.
7. The multilayered coated tablet according to claim 1, wherein the second layer is a
placebo layer.
8. The multilayered coated tablet according to claim 1, wherein the second layer is
water soluble or water swellable or water insoluble and helps in the division of the tablet
into different layers.
9. The multilayered coated tablet according to claim 8, wherein the second layer
comprises microcrystalline cellulose, corn starch or lactose and optionally a drug.
10. The multilayered coated tablet according to claim 9, wherein the second layer
comprises an immediate-release drug layer.
11. The multilayered coated tablet according to claim 10, wherein the three layers
contain the same drug.
12. The multilayered coated tablet according to claim 10, wherein the three layers
contain different drugs.
13. The multilayered coated tablet according to claim 10, wherein two layers contain the
same drug and a third layer contains a different drug.
14. The multilayered coated tablet according to claim 10, wherein the first and third
layers provide an extended-release of drug.
15. The multilayered coated tablet according to claim 10, wherein the first layer provides
an immediate-release of the drug and third layer provides an extended-release of the drug,
provided that the drugs in first and second layer are different.
16. The multilayered coated tablet according to claim 1, wherein the coating on the
tablet is a delayed-release coating.
17. The multilayered coated tablet according to claim 16, wherein the delayed-release
coating contains orifice on one side of the tablet.
18. The multilayered coated tablet according to claim 16, wherein the delayed-release
coating contains orifices on both sides of the tablet.
19. The multilayered coated tablet according to claim 16, wherein the delayed-release
coating contains one or more pore-forming agents.
20. The multilayered coated tablet according to claim 16, wherein the delayed-release
coating contains orifice on one side of the tablet and a pore-forming agent.
21. The multilayered coated tablet according to claim 16, wherein the delayed-release
coating contains orifices on both sides of the tablet and a pore-forming agent in it.
22. The multilayered coated tablet according to claim 19, wherein the pore-forming
agent used in the delayed-release coating is a hydrophilic substance or a hydrophobic
substance or a combination of both hydrophilic and hydrophobic substances, and is from
the group consisting of sodium chloride, potassium chloride, and magnesium salts, lactose,
sucrose, sorbitol, and mannitol, polyvinyl alcohols and glycols, such as polyethylene
glycol and propylene glycol; hydroxypropyl celluloses, hydroxy propyl methycelluloses;
methacrylic acid copolymers; croscarmellose sodium, crospovidone sodium starch
glycolate, talc, silicon dioxide, polyvinylpyrrolidones, gelling agents such as carbopol, and
xanthan gum; and any mixtures thereof.
23. The multilayered coated tablet according to claim 16, wherein the delayed-release
polymer used in the delayed-release coating is selected from the group consisting of
cellulose acetate phthalate (CAP), cellulose acetate trimelletate (CAT), poly(vinyl
acetate)phthalate (PVAP), hydroxypropyl methylcellulose phthalate (HPMCP),
poly(methacrylate ethylacrylate) (1:1) copolymer (MA-EA), poly(methacrylate
methylmethacrylate) (1:1) copolymer (MA-MMA), poly(methacrylate
methylmethacrylate) ( 1:2) copolymer, (Eudragit® L-30-D Eudragit®L- 100-55),
Eudragit® L100, Eudragit® L12,5, Eudragit® S100, Eudragit® S12,5, Poly(methyl
acrylate-co-methyl methacrylate-co-methacrylic acid) 7:3: 1- (Eudragit FS30D),
hydroxypropyl methylcellulose acetate succinate (HPMCAS) and combinations thereof.
24. The multilayered coated tablet according to claim 16, wherein the delayed-release
coating further comprises an immediate-release drug layer over it.
25. The multilayered coated tablet according to claim 24, wherein the immediate-release
drug layer over the delayed-release coating layer contains the same drug as that of the
internal layers of the tablet.
26. The multilayered coated tablet according to claim 24, wherein the immediate-release
layer over the delayed-release coating layer contains a drug different than that of the
internal layers of the tablet.
27. The multilayered coated tablet according to claim 1, wherein the shape of the tablet
is capsular, circular or cylindrical.
28. The multilayered coated tablet according to claim 1, wherein the said tablet further
comprises pharmaceutically acceptable excipients selected from the group consisting of
adsorbents, antioxidants, acidifying agents, alkalizing agents, buffering agents, colorants,
flavorants, sweetening agents, antiadherents, binders, diluents, direct compression
excipients, disintegrants, glidants, lubricants, opaquants and polishing agents.