Details for Patent: 8,318,745

Title:	Crystalline forms of (6R)-L-erythro-tetrahydrobiopterin dihydrochloride
Abstract:	Crystal forms of (6R)-L-erythro-tetrahydrobiopterin dihydrochloride, hydrates and solvates and processes for their preparation are provided. These crystal forms are either intermediates for the preparation of stable polymorphic form B or are suitable for solid formulations.
Inventor(s):	Moser; Rudolf (Schaffhausen, CH), Groehn; Viola (Dachsen, CH), Egger; Thomas (Kempthal, CH), Blatter; Fritz (Reinach, CH)
Assignee:	Merck & CIE (Schaffhausen, CH)
Filing Date:	Dec 03, 2009
Application Number:	12/629,963
Claims:	1. A pharmaceutical tablet formulation comprising a purified crystalline polymorph of (6R)-L-erythro-tetrahydrobiopterin dihydrochloride, form B, which exhibits a characteristic X-ray powder diffraction pattern comprising characteristic peaks expressed in d-values (.ANG.): 8.7.+-.0.1-0.2.degree. (vs), 5.63.+-.0.1-0.2.degree. (m), 4.76.+-.0.1-0.2.degree. (m), 4.40.+-.0.1-0.2.degree. (m), 4.00.+-.0.1-0.2.degree. (s), 3.23.+-.0.1-0.2.degree. (s) and 3.11.+-.0.1-0.2.degree. (vs); or which exhibits a characteristic X-ray powder diffraction pattern substantially as exhibited in FIG. 2; and polyvinylpyrrolidone as a pharmaceutically acceptable ingredient and/or dicalcium phosphate as an excipient, wherein the polyvinylpyrrolidone is a biologically degradable polymer which may be linear, branched or crosslinked. 2. A pharmaceutical tablet formulation comprising a purified crystalline polymorph of (6R)-L-erythro-tetrahydrobiopterin dihydrochloride, form B, which exhibits a characteristic X-ray powder diffraction pattern comprising characteristic peaks expressed in d-values (.ANG.): 8.7.+-.0.1-0.2.degree. (vs), 6.9.+-.0.1-0.2.degree. (w), 5.90.+-.0.1-0.2.degree. (vw), 5.63.+-.0.1-0.2.degree. (m), 5.07.+-.0.1-0.2.degree. (m), 4.76.+-.0.1-0.2.degree. (m), 4.40.+-.0.1-0.2.degree. (m), 4.15.+-.0.1-0.2.degree. (w), 4.00.+-.0.1-0.2.degree. (s), 3.95.+-.0.1-0.2.degree. (m), 3.52.+-.0.1-0.2.degree. (m), 3.44.+-.0.1-0.2.degree. (w), 3.32.+-.0.1-0.2.degree. (m), 3.23.+-.0.1-0.2.degree. (s), 3.17.+-.0.1-0.2.degree. (w), 3.11.+-.0.1-0.2.degree. (vs), 3.06.+-.0.1-0.2.degree. (w), 2.99.+-.0.1-0.2.degree. (w), 2.96.+-.0.1-0.2.degree. (w), 2.94.+-.0.1-0.2.degree. (m), 2.87.+-.0.1-0.2.degree. (w), 2.84.+-.0.1-0.2.degree. (s), 2.82.+-.0.1-0.2.degree. (m), 2.69.+-.0.1-0.2.degree. (w), 2.59.+-.0.1-0.2.degree. (w) and 2.44.+-.0.1-0.2.degree. (w); and polyvinylpyrrolidone as a pharmaceutically acceptable ingredient and/or dicalcium phosphate as an excipient, wherein the polyvinylpyrrolidone is a biologically degradable polymer which may be linear, branched or crosslinked. 3. A pharmaceutical tablet formulation comprising a purified crystalline polymorph of (6R)-L-erythro-tetrahydrobiopterin dihydrochloride, form B, which exhibits a characteristic X-ray powder diffraction pattern substantially as exhibited in FIG. 2; and polyvinylpyrrolidone as a biologically degradable polymeric binder and/or dicalcium phosphate as an excipient. 4. The pharmaceutical tablet formulation according to claim 1, wherein the purified crystalline polymorph of (6R)-L-erythro-tetrahydrobiopterin dihydrochloride is of at least about 98% purity by high performance liquid chromatography. 5. A process for preparing a pharmaceutical tablet formulation according to claim 1 comprising (a) providing a purified crystalline polymorph of form B of (6R)-L-erythro-tetrahydrobiopterin dihydrochloride of at least about 98% purity by high performance liquid chromatography, and (b) mixing the purified crystalline polymorph with polyvinylpyrrolidone and/or dicalcium phosphate. 6. A pharmaceutical tablet formulation prepared by the process of claim 5. 7. A pharmaceutical tablet formulation according to claim 1, further comprising folate alone or together with arginine. 8. A pharmaceutical tablet formulation according to claim 1, further comprising a lubricant, a vitamin and a sugar. 9. A pharmaceutical tablet formulation according to claim 2, further comprising a lubricant, a vitamin and a sugar. 10. A pharmaceutical tablet formulation according to claim 3, further comprising a lubricant, a vitamin and a sugar. 11. A pharmaceutical tablet formulation according to claim 1, wherein the polyvinylpyrrolidone is a biologically degradable crosslinked polymer. 12. A pharmaceutical tablet formulation according to claim 2, wherein the polyvinylpyrrolidone is a biologically degradable crosslinked polymer. 13. A pharmaceutical tablet formulation according to claim 3, wherein the polyvinylpyrrolidone is a biologically degradable crosslinked polymer. 14. The pharmaceutical tablet formulation according to claim 2, wherein the purified crystalline polymorph of (6R)-L-erythro-tetrahydrobiopterin dihydrochloride is of at least about 98% purity by high performance liquid chromatography. 15. The pharmaceutical tablet formulation according to claim 3, wherein the purified crystalline polymorph of (6R)-L-erythro-tetrahydrobiopterin dihydrochloride is of at least about 98% purity by high performance liquid chromatography. 16. The pharmaceutical tablet formulation according to claim 1, wherein the formulation comprises polyvinylpyrrolidone and dicalcium phosphate. 17. The pharmaceutical tablet formulation according to claim 2, wherein the formulation comprises polyvinylpyrrolidone and dicalcium phosphate. 18. The pharmaceutical tablet formulation according to claim 3, wherein the formulation comprises polyvinylpyrrolidone and dicalcium phosphate. 19. The pharmaceutical tablet formulation according to claim 1, wherein form B exhibits a characteristic X-ray powder diffraction pattern with the following characteristic peaks expressed in d-values (.ANG.): 8.7 (vs), 5.63 (m), 4.76 (m), 4.40 (m), 4.00 (s), 3.23 (s) and 3.11 (vs). 20. The pharmaceutical tablet formulation according to claim 2, wherein form B exhibits a characteristic X-ray powder diffraction pattern with the following characteristic peaks expressed in d-values (.ANG.): 8.7 (vs), 6.9 (w), 5.90 (vw), 5.63 (m), 5.07 (m), 4.76 (m), 4.40 (m), 4.15 (w), 4.00 (s), 3.95 (m), 3.52 (m), 3.44 (w), 3.32 (m), 3.23 (s), 3.17 (w), 3.11 (vs), 3.06 (w), 2.99 (w), 2.96 (w), 2.94 (m), 2.87 (w), 2.84 (s), 2.82 (m), 2.69 (w), 2.59 (w) and 2.44 (w). 21. The pharmaceutical tablet formulation according to claim 19, wherein the formulation comprises polyvinylpyrrolidone and dicalcium phosphate. 22. The pharmaceutical tablet formulation according to claim 20, wherein the formulation comprises polyvinylpyrrolidone and dicalcium phosphate.