1. An amorphous mirabegron.
2. A process for preparing amorphous mirabegron of claim 1, comprising:

a) providing a solution of mirabegron in a solvent or mixture of solvents;
b) removing solvent from the solution obtained in step a), and
c) isolating an amorphous form of mirabegron

3. An amorphous solid dispersion of mirabegron together with one or more pharmaceutically acceptable carriers.
4. The amorphous solid dispersion of mirabegron of claim 3, wherein the pharmaceutically acceptable carrier is at least one selected from gelatines, ovalbumin, soybean proteins, gum arabic, non-sucrose fatty acid esters, starches, modified starches, cellulose, methylcellulose (MC), ethylcellulose (EC), hydroxy ethylcellulose (HEC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), polycarbophil, polyethylene glycol (PEG), polyethylene oxides, polyoxyalkylene derivatives, polymethacrylates, polyvinyl pyrrolidone (PVP, povidone), polyvinyl acetate (PVAc), PVP-vinylacetate-copolymer (PVP-VA), Kollidon VA 64 (a vinylpyrrolidone- vinyl acetate copolymer), lactose, sorbitol, mannitol, maltitol, saccharose, Isomalt, cyclodextrins such as a-cyclodextrins, P-cyclodextrins, y-cyclodextrins and hydroxyl-propyl-P-cyclodextrins, sodiumcarboxymethylcellulose, sodium alginate, xantham gum, caavageenan, locust bean gum (ceratonia), chitosan, guar gum, cross-linkedhighamylase starch, and cross-linked polyacrylic acid (carbopol).
5. An amorphous solid dispersion of mirabegron of claim 3, wherein the pharmaceutically acceptable carrier is povidone.
6. The amorphous solid dispersion of mirabegron of claim 3 to 5, wherein the ratio of at least one pharmaceutically carrier to the mirabegron is at least about 1:2 (w/w) to about (2:1) (w/w).
7. A process for preparing the amorphous solid dispersion of mirabegron of any of claims 3 to 6, comprising:

a) providing a solution of mirabegron in combination with one or more pharmaceutically acceptable carriers in a solvent or mixture of solvents;
b) removing the solvent from the solution or suspension obtained in step a) or combining the solution obtained in step a) with an anti-solvent, and
c) isolating solid dispersion of amorphous mirabegron together with one or more pharmaceutically acceptable carrier.

8. A solid pharmaceutical formulation comprising the amorphous mirabegron or solid dispersion of amorphous mirabegron of any of claims 1 to 7 and one or more pharmaceutically acceptable carrier.
9. Use of amorphous mirabegron or amorphous solid dispersion of mirabegron according to any of claims 1 to 7 together with at least one pharmaceutically acceptable carrier, for the tre atment of a disease associated with overactive bladder.
10. A process for the preparation of a-form crystal of mirabegron comprising:

a) dissolving mirabegron in a solvent selected from methanol, ethanol, tetrahydrofuran, ethyl acetate, toluene or mixtures thereof to provide a solution;
b) cooling the solution obtained in step a), and
c) isolating a-form crystal of mirabegron.
11. A process for the preparation of a-form crystal of mirabegron comprising:
a) dissolving mirabegron in a mixture of methanol and water to provide a solution;
b) cooling the solution obtained in step a), and
c) isolating a-form crystal of mirabegron.
12. A process for the preparation of a-form crystal of mirabegron comprising:
a) providing a solution of mirabegron in a solvent selected from
tetrahydrofuran, methanol, ethanol, acetone, acetonitrile,l,4-dioxane, methyl isobutyl ketone, chlorobenzene or mixtures thereof;

b) adding an anti-solvent to the solution of step a), selected from cyclohexane, methylcyclohexane, n-heptane, diisopropyl ether, methyl tertiary butyl ether, toluene, water, provided that when methanol is used as a solvent then anti-solvent is other than water; and
c) isolating a-form crystal of mirabegron.
13. A process for the preparation of a-form crystal of mirabegron comprising:
a) dissolving mirabegron in acetone to provide a solution;
b) adding the solution obtained from step a) to methylcyclohexane, and
c) isolating a-form crystal of mirabegron.

14. A solid pharmaceutical formulation comprising a-form crystal of mirabegron obtained according to any of claims 10 to 13 and one or more pharmaceutically acceptable carrier.
15. Use of a-form crystal of mirabegron obtained according to any of claims 10 to 13 together with at least one pharmaceutically acceptable carrier for the treatment of a disease associated with overactive bladder.

1. A process for preparing amorphous mirabegron comprising:
c) providing a solution of mirabegron in a solvent or mixture of solvents;
d) removing solvent from the solution obtained in step a), and
e) isolating an amorphous form of mirabegron.
2. A process for preparing amorphous solid dispersion of mirabegron comprising:
d) providing a solution of mirabegron in combination with pharmaceutically acceptable carriers in a solvent or mixture of solvents;
e) removing the solvent from the solution or suspension obtained in step a) or combining the solution obtained in step a) with an anti-solvent, and
f) isolating solid dispersion of amorphous mirabegron together with one or more pharmaceutically acceptable carrier.
3. A process as claimed in claim 2, wherein the pharmaceutically acceptable carriers
in step a) is selected from gelatines, ovalbumin, soybean proteins, gum arabic,
non-sucrose fatty acid esters, starches, modified starches, cellulose,
methylcellulose (MC), ethylcellulose (EC), hydroxy ethylcellulose (HEC),
hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC),
polycarbophil, polyethylene glycol (PEG), polyethylene oxides, polyoxyalkylene
derivatives, polymethacrylates, polyvinyl pyrrolidone (PVP, povidone), polyvinyl
acetate (PVAc), PVP-vinylacetate-copolymer (PVP-VA), Kollidon VA 64 (a
vinylpyrrolidone- vinyl acetate copolymer), lactose, sorbitol, mannitol, maltitol,
saccharose, Isomalt, cyclodextrins like a-cyclodextrins, p-cyclodextrins, y-
cyclodextrins and hydroxyl-propyl-(3-cyclodextrins,
sodiumcarboxymethylcellulose, sodium alginate, xantham gum, caavageenan,
locust bean gum (ceratonia), chitosan, guar gum, cross-linkedhighamylase starch,
and cross-linked polyacrylic acid (carbopol).

4. A process as claimed in claim 2, wherein the pharmaceutical^ acceptable carrier is povidone.
5. A process as claimed in claim 2, wherein the ratio of pharmaceutically carrier to the mirabegron is in the range of 1:2 (w/w) to (2:1) (w/w).