The present invention relates to crystal modifications of N-{(2R)-2-[({[3,3-dibutyl-7-(methyl-thio)-1,1-dioxido-5-phenyl-2,3,4,5-tetrahydro-1,5-benzothiazepin-8-yl]oxy}acetyl)amino]-2-phenylethanolyl}glycine (elobixibat), more specifically crystal modifications I, IV, MeOH-1, EtOH-1, 1-PrOH-1 and 2-PrOH-1. The invention also relates to a process for the preparation of these crystal modifications and to a pharmaceutical composition comprising crystal modification IV.
