Process for preparing crystalline polymorphic forms of (6R)-L-erythro-tetrahydrobiopterin dihydrochloride

摘要

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.