Patent ID: 8318745

Claim:
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 (Å): 8.7±0.1-0.2° (vs), 5.63±0.1-0.2° (m), 4.76±0.1-0.2° (m), 4.40±0.1-0.2° (m), 4.00±0.1-0.2° (s), 3.23±0.1-0.2° (s) and 3.11±0.1-0.2° (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.