The present invention concerns novel crystalline forms of {5-(4-bromo-phenyl)-6-[2-(5-bromo-pyrimidin-2-yloxy)-ethoxy]-pyrimidin-4-yl}-sulfamide, processes for the preparation thereof, pharmaceutical compositions comprising said crystalline forms, pharmaceutical compositions prepared from such crystalline forms, and their use as endothelin receptor antagonists. It also relates to new uses of {5-(4-bromo-phenyl)-6-[2-(5-bromo-pyrimidin-2-yloxy)-ethoxy]-pyrimidin-4-yl}-sulfamide, either alone or in combination with other active ingredients or therapeutic agents.本發明係關於一種{5-(4-溴-苯基)-6-[2-(5-溴-嘧啶-2-基氧基)-乙氧基]-嘧啶-4-基}-磺醯胺之新穎結晶形式、其製備方法、包含該結晶形式之醫藥組合物、自此結晶形式製備之醫藥組合物及其等作為內皮素受體拮抗劑之用途。其亦係關於{5-(4-溴-苯基)-6-[2-(5-溴-嘧啶-2-基氧基)-乙氧基]-嘧啶-4-基}-磺醯胺單獨或與其他活性成分或治療劑組合之新穎用途。