FIELD OF THE INVENTION:
The present invention relates to novel amorphous form of 5-[4-[2-(N-methyl-N-(2-pyridyl) amino) ethoxy]-benzyl] -2,4 -thiazolidinedione maleate (Rosiglitazone Maleate), and process for the preparation there of. The Rosiglitazone Maleate is represented by the formula (I):

Rosiglitazone and its pharmaceutically acceptable salts are useful as pharmaceuticals, in particular, as an insulin-sensitizing agent, for the treatment of diabetes(Type II). BACKGROUND OF THE INVENTION:
U.S.Patent 5,002,953 and 5,002,953,incorporated herein by reference, describes method of preparation of5-[4-[2-(N-methyl-N-(2-Pyridyl)amino)ethoxy]-benzyl]-2,4-thiazohdinedione maleate of Formula (I) is disclosed, which includes :
1, reduction of 5-[4-[2-(N-methyl-N-(2-pyridyl)amino)ethoxy]-benzylidine]-2,4-
thiazolidinedione under hydrogen gas in presence of 10% palladium on charcoal.
2. subsequent conversion of the 5[4-[2-(N-methyl-N-(p-pyridyl)amino)ethoxy]-
benzyl] -2,4 - thiazolidinedione thus obtained to its pharmaceutically acceptable
salts.

Many of other patents (WO 99/31095, WO 00/64892, WO 99/31094, WO 00/64896, WO
99/31093, WO 00/64893 and WO 02/26737 Al), incorporated herein by reference, describe
the crystalline compounds for Rosiglitazone Maleate but none of these patents describes the
existence of an amorphous form of Rosiglitazone Maleate.
No relevant references of Rosiglitazone Maleate amorphous polymorphic form were
disclosed till date.
It has been disclosed earlier that the amorphous forms in a number of drugs exhibit different
dissolution characteristics and in some cases different bioavailability patterns compared to
crystalline forms [Konne T., Chem. Pharm. Bull. 38, 2003 (1990)]. For some therapeutic
indications one bioavailability pattern may be favoured over another. An amorphous form of
Cefuroxime axetil is a good example for exhibiting higher bioavailability than the
crystalline form.
Hence, the first object of the present invention is to provide the amorphous form of
Rosightazone Maleate.
The second object of the present invention is to prepare the amorphous form of
Rosiglitazone Maleate.
The process of the present invention is simple, non-hazardous, eco-friendly and well suited
for commercial production.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS:
FIG.l: X-Ray powder diffractogram of amorphous form of Rosiglitazone Maleate.

SUMMARY OF THE INVENTION:
In accordance with one aspect,the invention provides a novel amorphous form of
RosigUtazone Maleate.Preferably,the amorphous form of Rosiglitazone maleate has an X-
ray powder diffraction pattern ,depicted in FIG.l.
In accordance with another aspect, the invention provides a process for preparation of the
amorphous form of Rosiglitazone maleate that comprises the dissolution of Rosiglitazone
Maleate in nitrile solvents such as acetonitrile, propionitrile and the like or in alcohols such
as methanol, ethanol and the like followed by complete distillation of solvent using vacuum
to afford the novel amorphous form of Rosiglitazone Maleate.The process of the invention
are believed to be simple, non-hazardous, eco-fhendly and well suited for commercial
production.
DETAILED DESCRIPTION OF THE INVENTION:
In the preferred embodiment the present invention relates a novel amorphous form of
Rosiglitazone Maleate.
The amorphous form of Rosiglitazone Maleate is characterized by X-ray diffractogram,
which is measured on Bruker Axe, D8 Advance Powder X-ray Diffractometer with Cu K
alpha-1 Radiation source.
In the preferred embodiment provides the process for the preparation of Rosiglitazone
Maleate, which comprises;
(i) Dissolving Rosiglitazone Maleate in nitrile solvents such as acetonitrile, propionitrile and the like, preferably acetonitrile at heating; or in alcohols such as methanol or ethanol and the like, preferably methanol at heating;

(ii) distilling off the solvent from the reaction mixture of step (i) under vacuum at below 75 ° C;
(iii) gently scratching the compound of step (ii) to take out the compound to afford
the novel amorphous form of Rosiglitazone Maleate.
The amorphous form of Rosiglitazone Maleate obtained in the above process characterized
by the X-ray powder diffraction pattern is substantially as depicted in FIG. 1.
The characteristic X-ray diffractogram shows a plain halo with no peaks, which is
characteristic of the amorphous nature of product.
The process of the invention are believed to be simple, non-hazardous, eco-friendly and well
suited for commercial production.
The amorphous form of present invention is usefiil for pharmaceutical applications.
The Rosiglitazone maleate has been prepared as per the process disclosed in application
262/MAS/2001.
The process of the present invention will be explained in more detail with reference to the
following examples, which are provided by way of illustration only and should not be
constructed as limit to the scope of the reaction in any maimer.
Process for the preparation of amorphous form of Rosiglitazone maleate. EXAMPLE-!:
Dissolved 20 grams of Rosiglitazone Maleate in 600 ml of methanol under stirring heated to 60 to 70 °C. Distilled off the solvent completely under reduced pressure at 60 to 70 °C. Scratch the separated solid to get the desired amorphous form of Rosiglitazone Maleate
(18.5 grams, 92.5% of yield).
EXAMPLE-2:
Dissolved 20 grams of Rosiglitazone Maleate in 600 ml of acetonitrile under stirring heated to 60 to 70 '^C. Distilled off the solvent completely under reduced pressure at 60 to 70 °C.

Scratch the separated solid to get the desired amorphous form of Rosiglitazone Maleate
(18.5 grams, 92.5% of yield).
DETAILED DESCRIPTION OF ACCOMPANYING DRAWINGS:
Amorphous Rosiglitazone Maleate prepared according to the process of the present
invention is characterized by its X-ray Powder Diffraction pattern (FIG. 1).
Vertical axis: hitensity (CPS); Horizontal axis: Two Theta degrees).
X-ray Powder Diffraction pattern (FIG. 1) shows no significant peaks, which is
characteristic of amorphous form.

We claim;
1. Novel amorphous form of 5-[4-[2-(N-methyl-N-(2-pyridyl) amino) ethoxy]-benzyl] -
2,4 -thiazolidinedione maleate (Rosiglitazone Maleate).
2. Novel amorphous form of 5-[4-[2-(N-methyl-N-(2-pyridyl) amino) ethoxy]-benzyl] -2,4 -thiazolidinedione maleate (Rosiglitazone Maleate) according to claim 1 is characterized by X-Ray Powder Diffractogram, which is substantially as depicted in Figure (1).
3. The process for the preparation of novel amorphous form of Rosiglitazone maleate which comprises,
i) dissolving Rosiglitazone Maleate in nitrile solvents such as acetonitrile,
propionitrile and the like , preferably acetonitrile at heating; or in alcohols such as methanol or ethanol and the like, preferably methanol at heating;
ii) distilling the solvent from the reaction solution completely;
iii) Scratching solid by using conventional methods to afford the novel amorphous form of Rosiglitazone maleate
4. The process for the preparation of novel amorphous form of 5-[4-[2-(N-methyl-N
-(2-pyridyl) amino) ethoxy]-benzyl] -2,4 -thiazolidinedione maleate (Rosiglitazone Maleate), which is substantially as here in described and exemplified.