Polymorphs

1. A method of preparing an anhydrous polymorph A of the compound 1-[(4-methyl-quinazolin-2-yl)methyl]-3-methyl-7-(2-butyn-1-yl)-8-(3-(R)-amino-piperidin-1-yl)-xanthine, the method comprising:

heating polymorph B or a mixture of polymorphs A and B to temperatures>40° C.; wherein

said anhydrous polymorph A melts at 206±3° C., and

said anhydrous polymorph A exhibits an X-ray powder diagram having characteristic reflections at the following d values: 11.59 Å, 7.60 Å, 7.15 Å, 3.86 Å, 3.54 Å and 3.47 Å;

and wherein

said anhydrous polymorph B transforms reversibly into the polymorph A at temperature of 10-40° C., and

said anhydrous polymorph B exhibits an X-ray powder diagram having characteristic reflections at the following d values: 11.3 Å, 9.36 Å, 7.48 Å, 7.0 Å and 3.77 Å.

2. The method according to claim 1 , wherein anhydrous polymorph A has an X-ray powder diagram as shown in FIG. 3 .

3. The method of claim 1 , wherein anhydrous polymorph A is characterized in that the reflection at 11.59 Å in the X-ray powder diagram has a relative intensity of 100% and the X-ray powder diagram exhibits no reflections having a relative intensity of 1% or more at the following d values: 11.3 Å, 9.36 Å, 7.48 Å, and 7.0 Å.

4. The method according to claim 1 , wherein polymorph A is characterised by the follow lattice metrics:

Symmetry:

monoclinic

space group:

P

a:

16.16(2)

Å

b:

17.02(1)

Å

c:

18.18(2)

Å

β:

100.95(6)

°

cell volume:

4907(11)

Å 3 .

5. The method according to claim 1 wherein anhydrous polymorph B has an X-ray powder diagram as shown in FIG. 4 .

6. The method of claim 1 , wherein anhydrous polymorph B is characterized in that the reflection at 11.3 Å in the X-ray powder diagram has a relative intensity of 100% and the X-ray powder diagram exhibits no reflections having a relative intensity of 1% or more at the following d values: 11.59 Å, 7.60 Å, and 7.15 Å.

7. The method according to claim 1 , wherein polymorph B is characterised by its lattice metrics:

Symmetry:

monoclinic

space group:

P2 1 /c (# 14)

a:

15.23(1)

Å

b:

16.94(1)

Å

c:

18.79(1)

Å

β:

95.6(2)

°

cell volume:

4823(3)

Å 3 .

8. A method of preparing a medicament, the method comprising

i) preparing the anhydrous polymorph A by the method of claim 1 , and

ii) combining the anhydrous polymorph A with one or more inert carriers to provide a medicament containing 0.1% to 0.5%, or 0.5% to 1.5%, or 1% to 3% of the anhydrous polymorph A based on the total weight of the polymorph A and the one or more inert carriers.

9. A method of preparing anhydrous polymorph A or B, or a mixture thereof, of the compound 1-[(4-methyl-quinazolin-2-yl)methyl]-3-methyl-7-(2-butyn-1-yl)-8-(3-(R)-amino-piperidin-1-yl)-xanthine, the method comprising crystallizing polymorph A or B, or a mixture thereof, from a solution of 1-[(4-methyl-quinazolin-2-yl)methyl]-3-methyl-7-(2-butyn-1-yl)-8-(3-(R)-amino-piperidin-1-yl)-xanthine in ethanol,

wherein anhydrous polymorph A is characterised in that it melts at 206±3° C., and further characterised in that it exhibits an X-ray powder diagram having characteristic reflections at the following d values: 11.59 Å, 7.60 Å, 7.15 Å, 3.86 Å, 3.54 Å and 3.47 Å,

wherein anhydrous polymorph B is characterised in that it transforms reversibly into polymorph A at a temperature of 10-40° C., and further characterised in that it exhibits an X-ray powder diagram having characteristic reflections at the following d values: 11.3 Å, 9.36 Å, 7.48 Å, 7 Å and 3.77 Å.

10. A method of preparing a medicament, the method comprising

i) preparing the anhydrous polymorph A or B, or a mixture thereof, by the method of claim 9 , and

ii) combining the anhydrous polymorph A or B, or a mixture thereof, with one or more inert carriers to provide a medicament containing 0.1% to 0.5%, or 0.5% to 1.5%, or 1% to 3% of the anhydrous polymorph A or B, or a mixture thereof, based on the total weight of the polymorph A or B and the one or more inert carriers.