Synonyms: Cyclopenta[b]pyrrole-2-pentanoicacid, 1,4,5,6-tetrahydro-5-hydroxy-4-(3-hydroxy-1-octenyl)-1-phenyl-,monopotassium salt, [4R-[4a(1E,3S*),5b]]-;Cyclopenta[b]pyrrole-2-pentanoic acid,1,4,5,6-tetrahydro-5-hydroxy-4-[(1E,3S)-3-hydroxy-1-octenyl]-1-phenyl-,monopotassium salt, (4R,5R)- (9CI); Piriprost potassium; U 60257B