novel forms of ]- 2 -- β , δdihydroxy - 5 - methylethyl )- 3 - phenyl - 4 - carbonyl ]- 1 - h - pyrrole - 1 - heptanoic acid hemi calcium salt designated form xx , form xxi , form xxii , form xxiii , form xxiv , forms xxv , form xxvii , form xxviii , form xxxix , and forms xxx , characterized by their x - ray powder diffractor , solid state nmr , and / or raman spectroscopy are describes as well as methods for the preparation and pharmaceutical composition of the same , which are useful as agents for treating hyperlipidemia , hypercholesterolemia , osteoporosis , benign prostatic hyperplasia and alzheimer ) disease .