Synonyms: Spiro[2H-isoindole-2,1′-piperazinium], (3aR,7aR)-4′-(1,2-benzisothiazol-3-yl)octahydro-spiro[2H-isoindole-2,1′-piperazinium] Monomethanesulfonate, (3aR-trans)-4′-(1,2-benzisothiazol-3-yl)octahydro-spiro[2H-isoindole-2,1′-piperazinium] Monomethanesulfonate, Lurasidone Impurity B