Polymorphic forms of a GABA
Two new crystalline monhydrates and two new crystalline anhydrates of gaboxadol are disclosed together with methods for preparing them.
1. The compound gaboxadol monohydrate in a crystalline form selected from:
(a) form I which is characterised by an X-ray powder diffraction spectrum in 2θ values using CuKα radiation having a peak at 11.5°; and
(b) form II which is characterised by an X-ray powder diffraction spectrum in 2θ values using CuKα radiation having a peak at 25.2°.
2. The compound of claim 1 which is crystalline gaboxadol monohydrate of form II which is characterised by an X-ray powder diffraction spectrum in 2θ values using CuKα radiation having a peak at 25.2°.
3. The compound of claim 2 which is additionally characterised by solid state 13 C NMR chemical shifts of 17.5, 40.3, 102.2, 158.5 and 172.5 ppm with reference to a value of 176.03 ppm for the carbonyl peak of glycine.
4. The compound gaboxadol anhydrate in a crystalline form selected from:
(a) form I which is characterised by an X-ray powder diffraction spectrum in 2θ values using CuKα radiation having a peak at 12.8°; and
(b) form II which is characterised by an X-ray powder diffraction spectrum in 2θ values using CuKα radiation having a peak at one or more of 16.0°, 24.7° and 28.4°.
5. The compound of claim 4 which is crystalline gaboxadol anhydrate of form II which is characterised by an X-ray powder diffraction spectrum in 2θ values using CuKα radiation having a peak at one or more of 16.0°, 24.7° and 28.4° in the absence of a peak at 12.8°.