FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION (See section 10; rule 13)
1. Title of the invention - EXTENDED RELEASE FORMULATIONS OF
ROPINIROLE
2. Applicants)
(a) NAME: ALEMBIC LIMITED
(b) NATIONALITY : An Indian Company
(C) ADDRESS: Alembic Campus, Alembic Road,
Vadodara-390 003, Gujarat, India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

EXTENDED RELEASE FORMULATIONS OF ROPINIROLE FIELD OF INVENTION
The present invention relates to extended release formulations of ropinirole.
BACKGROUND OF THE INVENTION
Parkinson's disease is a degenerative disorder of the central nervous system that is pathologically associated with deterioration of nuclear masses of the extrapyramidal system and a characteristic loss of melanin-containing cells from the basal ganglia, and more particularly the substantia nigra, of the brain. This loss and degeneration of dopamine producing cells results in a corresponding depletion of dopamine from the corpus striatum of the brain. Parkinson's disease is the second most prevalent neurodegenerative disease in the United States with an estimated 1 million Parkinson's patients with about 60,000 new cases being diagnosed annually.
Symptomatic therapies improve signs and symptoms without affecting the underlying disease state. Dopamine agonists provide symptomatic benefit by directly stimulating post-synaptic striatal dopamine receptors. Other medications used in the treatment of Parkinson's disease include MAO-B inhibitors.
Ropinirole is a non-ergoline dopamine agonist with high relative in vitro specificity and full intrinsic activity at the D2 and D3 dopamine receptor subtypes, binding with higher affinity to D3 than to D2 or D4 receptor subtypes. Its chemical structure, processes for its preparation and therapeutic uses thereof, are more fully described in EP 113964 Bl, WO 91/16306 Al and EP 300614 Bl, the contents of which are hereby incorporated by reference. Ropinirole is marketed as an immediate release tablet formulation, Requip® in the USA. Ropinirole has a solubility of 133 mg/ ml in water. It is rapidly absorbed after oral administration, reaching peak concentration in approximately 1-2 hours and has an elimination half-life of approximately 6 hours. The pharmacokinetics of Requip® are

similar in Parkinson's disease patients and patients with Restless Legs Syndrome which are the two approved indications of Requip®. Ropinirole is also available in the form of extended release tablets in the US market under trade name of Requip XL.
Various controlled release released formulations of ropinirole are known in the art. US 2003/0180359 Al and US 2007/0264336 Al disclose a multi-layer controlled release tablet containing one active layer containing the active ingredient having a mixed matrix of hydrophilic and lipophilic components and one or more barrier layers which limit the release surface of the active layer. A fundamental characteristic of these tablets is that, in both the layers i.e. the layer containing ropinirole and the barrier layer, lipophilic substances having HLB value of less than 10 and more preferably less than 5 are utilised. The active ingredient is not present in the barrier layer which is partially applied to the active layer by compression process.
WO 2007/052299 Al discloses a controlled release dosage form of ropinirole using a combination of a non-polymeric release retardant and pH independent non-swelling release retardant, where the non-swelling release retardant includes any excipient that does not swell in water or swells only moderately and does not include, excipients such as super disintegrants and polymers such as polyethylene oxide that swell voluminously in contact with water or aqueous media.
WO 2007/036952 Al discloses oral sustained release dosage forms of pharmaceutically active agents comprising a combination of non-swelling pH dependent release retardant and non-swelling pH independent release retardant.
There still exists a need for developing extended release compositions of highly water soluble active agents like ropinirole, having reduced initial burst release, convenient to formulate and exhibiting a desired dissolution profile.
The formulations of the present invention provide dosage forms in the form of tablets having ropinirole in the core with release control layer/s surrounding the core to achieve

the desired extended release profile for ropinirole. Also, the extended release formulations of the present invention are less complicated and use a minimum number of excipients. The release control layer of the extended release tablets surrounds the active core completely and is convenient to formulate as compared to the prior art processes involving the barrier layers or release controlling layers to be partially applied by compression process.
SUMMARY OF THE INVENTION
The present invention relates to an extended release tablet formulation of ropinirole. In one aspect, the invention relates to an extended release tablet comprising:
(a) an active core comprising ropinirole, a pH independent non-swelling release retardant, a hydrophilic cellulosic polymer and a viscosity-increasing agent, and
(b) a release control layer comprising a hydrophobic polymeric substance optionally with a low-viscosity hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids, wherein the release control layer completely surrounds the active core.
In another aspect, the invention relates to an extended release tablet comprising:
(a) an active core comprising ropinirole, a pH independent non-swelling release retardant,
a hydrophilic cellulosic polymer and a viscosity-increasing agent, and
(b) a release control layer comprising a low-viscosity hydrophilic cellulosic polymer
which swells and optionally, gels or erodes upon contact with aqueous liquids, wherein
the release control layer completely surrounds the active core.
In another aspect, the invention relates to a process for preparation of an extended release tablet, comprising the steps of:
a) mixing ropinirole, a pH independent non-swelling release retardant, a hydrophilic cellulosic polymer, a viscosity-increasing agent and at least one pharmaceutically acceptable excipient;
b) granulating the mixture of step (a);
c) compressing the product of step (b), to form the active core;

d) coating the product of step (c) with a release control layer comprising a hydrophobic polymeric substance optionally with a low-viscosity hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids
In another aspect, the invention relates to a process for preparation of an extended release tablet, comprising the steps of:
a) mixing ropinirole, a pH independent non-swelling release retardant, a hydrophilic cellulosic polymer, a viscosity-increasing agent and at least one pharmaceutically acceptable excipient;
b) granulating the mixture of step (a);
c) compressing the product of step (b), to form the active core;
d) coating the product of step (c) with a low-viscosity hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids and at least one pharmaceutically acceptable excipient.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to extended release tablet formulations of ropinirole. The term "ropinirole" as used herein includes ropinirole base and pharmaceutically acceptable salts or mixtures thereof. The chemical structure of ropinirole, processes for its preparation and therapeutic uses thereof, are more fully described in EP 113964 Bl, WO 91/16306 Al and EP 300614 Bl, the contents of which are herein incorporated by reference. Most preferably, ropinirole used in the tablets is in the form of a hydrochloride salt.
The term 'non-swelling' as used herein includes an excipient that does not swell in water or swells only moderately. The term 'release retardant' as used herein means any excipient that can retard the release of an active pharmaceutical ingredient and includes substances like polymers, waxes, fatty acids and the like or mixtures thereof. A pH independent release retardant is an excipient whose solubility is independent of pH and hence its performance does not depend on the pH of the environment it encounters.

Unless otherwise mentioned herein, the term '%' means percentage by weight of total weight of the tablet.
While working on the development of extended release tablets of Ropinirole, the present inventors surprisingly found that when ropinirole is formulated selectively, using a combination of release retarding or controlling substances or polymers, in the form of a tablet containing ropinirole in an active core and one or more release control layers surrounding the active core completely, the tablet achieves the desired drug release profile.
According to an embodiment of the invention there is provided, an extended release tablet comprising:
(a) an active core comprising ropinirole, a pH independent non-swelling release retardant, a hydrophilic cellulosic polymer and a viscosity-increasing agent, and
(b) a release control layer comprising a low-viscosity hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids, wherein the release control layer completely surrounds the active core.
According to an embodiment of the invention there is provided, an extended release tablet comprising:
(a) an active core comprising ropinirole, a pH independent non-swelling release retardant, a hydrophilic cellulosic polymer and a viscosity-increasing agent, and
(b) a release control layer comprising a hydrophobic polymeric substance optionally with a low-viscosity hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids, wherein the release control layer completely surrounds the active core.
The ropinirole containing extended release tablets as described herein may comprise of one or more pharmaceutically acceptable excipients selected from pH independent non-swelling release retardants, hydrophilic cellulosic polymers, viscosity-increasing agents,

hydrophobic polymeric substances, low-viscosity hydr0philic cellulosic polymers, diluent, binders, glidants or lubricants, colorants, preservatives or stabilizers.
The active core of the tablet contains ropinirole. Ropinirole may be present in a suitable amount, particularly in an amount ranging from about 0.05% to 80%; more particularly about 0.05% to 40% by weight of the tablet. Ropinirole may be of any suitable particle size or in any suitable polymorphic form.
The pH independent non-swelling release retardant, retards the release of ropinirole from the active core and is selected from the group comprising of polymer, wax, fatty acid and the like or mixtures thereof. The pH independent non-spelling release retardant may preferably be, a non-polymeric release retardant. A non-polymeric release retardant is one whose chemical structure is not comprised of repeating units of monomers. The non-polymeric release retardants include excipients such as fatty acids, long chain alcohols, tats and oil, waxes, phospholipids, ei'cosonoi'cfs, terpeness steroids and the face. More preferably, the non-polymeric release retardants include excipients such as natural waxes like flax wax, beeswax, petrolatum wax, Chinese wax, shellac wax, lanolin wax, sugarcane wax, spermaceti wax, carnauba wax, Japan wax, bayberry wax, candelilla wax, paraffin wax, microcrystalline wax, carbowax, and the like 0r mixtures thereof. Mixtures of these waxes set out above with the fatty acids may also be used. Other examples of the non-polymeric release retardants include hydrogenated castor oil, hydrogenated soybean oil, carbowax, glyceryl behenate, hydrogenated cottonseed oil, beeswax, hydrogenated palm oil, lanolin, macrogolglycerides lauriques, glyceryl balmitostearate, cetyl alcohol, polyglyceryl diisostearate, glyceryl stearate and mixtures thereof. The most preferred non-polymeric release retardants include glyceryl behenate, hydrogenated castor oil, stearic acid, cetyl alcohol and the like or mixtures thereof.
The pH independent non-swelling release retardant may be present in a suitable amount, such as in an amount from about 0.5 % to 20%, more particularly in an amount ranging from about 1 to 10%.

The viscosity-increasing agents reduce the release of ropinirole from the active core. Typical viscosity-increasing agents include agents such as sodium carboxymethylcellulose, carboxymethyl cellulose or a derivative (e.g. calcium carboxymethylcellulose), hydroxypropylcellulose with a molecular weight of from 100,000 to 4,000,000, a carboxyvinylpolymer, a carrageenan, a xanthan, alginic acid or a derivative (e.g. sodium or calcium alginate, propylene glycol alginate), ethylcellulose, methylcellulose, dextrin and/or maltodextrin or mixtures thereof. The viscosity-increasing agents may be present in an amount ranging from about 0.01 - 50%, more particularly in an amount ranging from about 0.05 - 20%.
The active core of the tablet may optionally contain disintegrants such as sodium starch glycolate, alginic acid, calcium carboxymethylcellulose, sodium carboxymethylcellulose, croscarmellose sodium, crospovidone, guar gum, sodium alginate, magnesium aluminium silicate, sodium starch glycolate, starches and the like or mixtures thereof used in suitable amount as known to person skilled in the art. The disintegrant may be present in an amount ranging from about 0 - 50 %, more particularly in an amount ranging from about 0-10%.
The active core of the tablet in general, contains a hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids. The hydrophilic cellulosic polymer possesses properties, such as the ability to imbibe external fluid and dissolve/erode over a period of time. Typical polymers include hydroxypropylmethyl cellulose, hydroxym.ethy I cellulose, hydroxypropylcellulose, hydroxyethylcellulose, carboxymethylcellulose, carboxyethylcellulose, sodium carboxymethylcellulose, hydroxypropylmethylftellulose, methylcellulose and the like.
The hydrophilic cellulosic polymer may be present in a suitable amount, such as in an amount from about 10-85 % by weight of the tablet, more particularly in an amount ranging from about 20 - 60%.

In order to promote the penetration of water and/or aqueous fluids in the release control layer or the active core, hydrophilic diluents, for example, mannitol, lactose, starches of different origins, sorbitol, xylitol, polyethylene glycol may be introduced in the formulation, or substances with wetting properties and/or those generally encouraging the penetration of water in the solid are preferably incorporated in the tablet in a suitable amount. The hydrophilic diluents may be present in an amount ranging from about 0-95 %, more particularly in an amount ranging from about 5 - 60%
The tablet may in general, contain one or more pharmaceutically acceptable tabletting excipients such as diluents, binders, lubricants or glidants and optionally colorants, preservatives or stabilizers in a suitable amount as known to a person skilled in the art. For example, the one or more excipients may be starch, mannitol, lactose, microcrystalline cellulose, sorbitol, xylitol, talc, stearic acid, sodium benzoate, magnesium stearate, colloidal silicon dioxide, maltodextrirn sugar, modified corn starch, inorganic salts such as calcium carbonate and/or cellulose derivatives such as wood cellulose and other excipients known to the person skilled in the art.
The inventors found that using of a hydrophobic polymeric substance in the release control layer with or without the presence of the low-viscosity hydrophilic cellulosic polymer helps to provide a better control over the initial burst release of ropinirole. The release control layer of the tablet in general, contains hydrophobic polymeric substances such as for example, ethyl cellulose, methacrylic acid polymers and copolymers, fatty acids and esters thereof, waxes, high molecular weight fatty alcohols and the like used in suitable amount as known to person skilled in the art. The hydrophobic polymeric substances may be present in an amount ranging from about 0.05 - 20 %, more particularly in an amount ranging from about 0.5 - 10 %.
The release control layer of the tablet in general, optionally contains a low-viscosity hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids and helps to make the drug release faster such as for example, low viscosity grades of hydroxypropylmethylcellulose.

The low viscosity hydrophilic cellulosic polymer with at least one pharmaceutically acceptable excipient in a coating composition may be applied as a separate release control layer other than the release control layer which includes the hydrophobic polymeric substance. The low viscosity hydrophilic cellulosic polymer may be present in an amount ranging from about 0.05 - 5 %, more particularly in an amount ranging from about 0.5 -3%.
Suitable coating adjuvants like titanium dioxide, polysorbate, detackifiers, polyethylene glycol, talc, colorants like iron oxides as known to the person skilled in the art, can be incorporated in the release control layer.
The extended release tablet formulations of the invention may be prepared by a process comprising the steps of:
a) mixing ropinirole, a pH independent non-swelling release retardant, a hydrophilic cellulosic polymer, a viscosity-increasing agent and at least one pharmaceutically acceptable excipient;
b) granulating the mixture of step (a);
c) compressing the product of step (b), to form the active core;
d) coating the product of step (c) with a release control layer comprising a hydrophobic polymeric substance optionally with a low-viscosity hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids
Also, the extended release tablet formulations of the invention may be prepared by a process, comprising the steps of:
a) mixing ropinirole, a pH independent non-swelling release retardant, a hydrophilic cellulosic polymer, a viscosity-increasing agent and at least one pharmaceutically acceptable excipient;
b) granulating the mixture of step (a);
c) compressing the product of step (b), to form the active core;

d) coating the product of step (c) with a low-viscosity hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids and at least one pharmaceutically acceptable excipient.
The extended release tablet formulations of the present invention may be prepared by pharmaceutical techniques using suitable equipment known to a person skilled in the art. For example pharmaceutical techniques used may be mixing, sifting, dry, wet or melt granulation, slugging, compaction, compression, extrusion and spheronisation, micronization and the like. The equipments used may be rapid mixer granulator, tablet compression machine, fluid bed dryer, planetary mixer, grating mill, commuting mill and the like. For example, the extended release tablets as described above may be prepared by a method as described hereafter. The components of the active core such as ropinirole, the pH independent non-swelling release retardant and optionally one or more diluents are mixed and granulated using dry, wet or melt granulation techniques, preferably dry granulation. The granules may be sized using a sifter having a suitable screen. The granules can then be compressed optionally after lubrication by a suitable lubricant to form the active core. The active core is subsequently coated with the release control layer having a hydrophobic polymeric substance optionally with a low-viscosity hydrophilic cellulosic polymer and suitable excipients to obtain an extended release tablet. The active core can be coated with more than one separate release control layers- one with the hydrophobic polymeric substance and one without the hydrophobic polymeric substance.
The extended release properties of the tablets of the present invention are demonstrated by monitoring the dissolution of the active ingredient using suitable methods known in the art. For example, the dissolution of the active ingredient is monitored for the tablet using the extended release USP Paddle Method is the Paddle Method described in US Pharmacopoeia, 26 (2003) using suitable sinkers to ensure that the dosage form does not adhere to the vessel.
While the present invention has been described in terms of its specific embodiments, certain modifications and equivalents will be apparent to those skilled in the art and are

intended to be included within the scope of the present invention. The invention may be further illustrated by the following non-limiting examples:


ii) Procedure:
1. Sift Hypromellose, starch 1500, Carboxymethyl cellulose sodium, PVPK-90 and hydrogenate castor oil through 40# sieve and mix it in polybag.
2. Weigh the Ropinirole Hydrochloride accurately and mix it with blend of step 1 by geometric mixing in blender. Mix Aerosil-200 and magnesium stearate with blend.
3. Prepare slug of the blend of step 3 using 20 mm punches on compression machine. Optionally prepare slugs/flakes by using roller compactor.
4. Mill the slugs/flakes using 1.5 mm sieve in multimill.
5. Separately, sift Aerosil-200 through 30# sieve and mix it with blend of step 4.
6. Sift Magnesium stearate through 60# sieve and mix it with blend of step 5.

7. Compress the lubricated blend in to tablets using 12X6 mm capsule shaped punches.
8. Coating of tablet by using Opadry coating (hydroxypropylmethylcellulose, polyethylene glycol, titanium dioxide, iron oxide red, talc) in a conventional coating pan.
Dissolution data - Ropinirole HC1 ER Tablets 2mg
Condition - 500 ml Citrate buffer pH 4.0 Medium, USP Type II (paddle) with sinkers at
lOOrpm



ii) Procedure:
1. Sift Hypromellose, starch 1500, Carboxymethyl cellulose sodium, PVPK-90 and hydrogenate castor oil through 40# sieve and mix it in polybag.
2. Weigh the Ropinirole Hydrochloride accurately and mix it with blend of step 1 by geometric mixing in blender. Mix Aerosil-200 and magnesium stearate with blend.
3. Prepare slug of the blend of step 3 using 20 mm punches on compression machine. Optionally prepare slugs/flakes by using roller compactor.
4. Mill the slugs/flakes using 1.5 mm sieve in multimill.
5. Separately, sift Aerosil-200 through 30# sieve and mix it with blend of step 4.
6. Sift Magnesium stearate through 60# sieve and mix it with blend of step 5.
7. Compress the lubricated blend in to tablets using 12X6 mm capsule shaped punches.
8. Functional coating of tablets with ethyl cellulose 7 cps.

9. Coating of tablet by using Opadry coating (hydroxypropylmethylcellulose,
polyethylene glycol, titanium dioxide, iron oxide red, talc) in a conventional
coating pan.
Example 3

ii) Procedure:
1. Sift Hypromellose, HPC M, HPC L and Lactose anhydrous through 20# sieve and mix it in polybag.

2. Weigh the drug accurately and mix it with blend of step 1 by geometric mixing in blender. Mix Aerosil-200 and magnesium stearate with blend.
3. Prepare slug of the blend of step 3 using suitable punches on compression machine. Optionally prepare slugs/flakes by using roller compactor.
4. Mill the slugs/flakes using suitable sieve in multimill.
5. Separately, sift Carboxymethyl cellulose sodium and Aerosil-200 through 40# sieve and mix it with blend of step 4.
6. Sift Magnesium stearate through 60# sieve and mix it with blend of step 5.
7. Compress the lubricated blend in to tablets using suitable tablet compression toolings
8. Coating of tablet by using Opadry coating (hydroxypropylmethylcellulose, polyethylene glycol, titanium dioxide, iron oxide red, talc) in a conventional coating pan.
Dissolution data - Ropinirole HC1 ER Tablets 2mg
Condition - 500 mL Citrate buffer pH 4.0 Medium, USP Type II (paddle) with sinkers at
100 rpm


ii) Procedure:
1. Sift Hypromellose, starch 1500, Carboxymethyl cellulose sodium, PVPK-90 and hydrogenate castor oil through 40# sieve and mix it in polybag.
2. Weigh the Ropinirole Hydrochloride accurately and mix it with blend of step 1 by geometric mixing in blender. Mix Aerosil-200 and magnesium stearate with blend.
3. Prepare slug of the blend of step 3 using suitable punches on compression machine. Optionally prepare slugs/flakes by using roller compactor.
4. Mill the slugs/flakes using suitable sieve in multimill.
5. Separately, sift Aerosil-200 through 30# sieve and mix it with blend of step 4.
6. Sift Magnesium stearate through 60# sieve and mix it with blend of step 5.
7. Compress the lubricated blend in to tablets using suitable tablet compression toolings.

8. Coating of tablets with ethyl cellulose 7 cps in opadry coating (hydroxypropylmethylcellulose, polyethylene glycol, titanium dioxide, iron oxide red, talc) in a conventional coating pan at 3%, 5% or 7% weight gain. Dissolution Data -
Condition - 500 mL Citrate buffer pH 4.0 Medium, USP Type II (paddle) with sinkers at lWrpm


We claim
1) An extended release tablet comprising:
(a) an active core comprising ropinirole, a pH independent non-swelling release retardant, a hydrophilic cellulosic polymer and a viscosity-increasing agent, and
(b) a release control layer comprising a hydrophobic polymeric substance optionally with a low-viscosity hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids, wherein the release control layer completely surrounds the active core.

2. The extended release tablet according to claim 1, wherein the pH independent non-swelling release retardant is selected from the group consisting of polymers, wax, fatty acids or mixtures thereof.
3. The extended release tablet according to claim 1, wherein the pH independent non-swelling release retardant is selected from the group consisting of hydrogenated castor oil, stearic acid or mixtures thereof.
4. The extended release tablet according to claim 1, wherein the hydrophilic cellulosic polymer is selected from the group consisting of hydroxypropylmethylcellulose, hydroxymethylcellulose, hydroxypropyl cellulose, hydroxyethylcellulose, carboxymethylcellulose, carboxyethylcellulose, methylcellulose or mixtures thereof.
5. The extended release tablet according to claim 1, wherein the viscosity-increasing agent is selected from the group consisting of sodium carboxymethylcellulose, carboxymethylcellulose, calcium carboxymethylcellulose, hydroxypropylcellulose, carboxyvinylpolymer, ethylcellulose, methylcellulose, dextrin, maltodextrin or mixtures thereof
6. . The extended release tablet according to claim 1, wherein the hydrophobic polymeric substance is ethylcellulose.

7. The extended release tablet according to claim 1, wherein the low-viscosity hydrophilic cellulosic polymer is hydroxypropylmethylcellulose.
8. A process for preparation of an extended release tablet, comprising the steps of:

a) mixing ropiniroie, a pH independent non-sweiiing reiease retardant, a hydrophiiic cellulosic polymer, a viscosity-increasing agent and at least one pharmaceutically acceptable excipient;
b) granulating the mixture of step (a);
c) compressing the product of step (b), to form the active core;
d) coating the product of step (c) with a release control layer comprising a hydrophobic polymeric substance optionally with a low-viscosity hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids
9. The process according to claim 8, wherein the step (b) involves slugging.
10. An extended release tablet comprising:
(a) an active core comprising ropinirole, a pH independent non-swelling release retardant,
a hydrophilic cellulosic polymer and a viscosity-increasing agent, and
(b) a release control layer comprising a low-viscosity hydrophilic cellulosic polymer
which swells and optionally, gels or erodes upon contact with aqueous liquids, wherein
the release control layer completely surrounds the active core.
11. The extended release tablet according to claim 10, wherein the pH independent non-swelling release retardant is selected from the group consisting of polymers, wax, fatty acids or mixtures thereof.
12. The extended release tablet according to claim 10, wherein the pH independent non-swelling release retardant is selected from the group consisting of hydrogenated castor oil, stearic acid or mixtures thereof.

13. The extended release tablet according to claim 10, wherein the hydrophilic cellulosic polymer is selected from the group consisting of hydroxypropylmethylcellulose, hydroxymethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, carboxymethylcellulose, carboxyethylcellulose, methylcellulose or mixtures thereof.
14. The extended release tablet according to claim 10, wherein the viscosity-increasing agent is selected from the group consisting of sodium carboxymethylcellulose, carboxymethylcellulose, calcium carboxymethylcellulose, hydroxypropylcellulose, carboxyvinylpolymer, ethylcellulose, methylcellulose, dextrin, maltodextrin or mixtures thereof.
15. The extended release tablet according to claim 10, wherein the low-viscosity
hydrophilic cellulosic polymer is hydroxypropylmethylcellulose.
16. A process for preparation of an extended release tablet, comprising the steps of:
a) mixing ropinirole, a pH independent non-swelling release retardant, a hydrophilic cellulosic polymer, a viscosity-increasing agent and at least one pharmaceutically acceptable excipient;
b) granulating the mixture of step (a);
c) compressing the product of step (b), to form the active core;
d) coating the product of step (c) with a low-viscosity hydrophilic cellulosic polymer which swells and optionally, gels or erodes upon contact with aqueous liquids and at least one pharmaceutically acceptable excipient.

17. The process according to claim 16, wherein the step (b) involves slugging.
18. An extended release tablet of ropinirole, substantially as herein described, particularly with reference to the foregoing examples.