amine salts of 3 -- 9 -- naphthyridin - 2 - yl )- nonanoic acid are potent antagonists of the integrin αvβ3 receptor and are useful for the prevention and / or treatment of osteoporosis and vascular restenosis , as well as conditions associated with excessive angiogenesis , such as macular degeneration , diabetic retinopathy , atherosclerosis , inflammatory arthritis , cancer , and metastatic tumor growth . the invention also relates to a process for the preparation of the novel salts as well as pharmaceutical compositions containing the salts and methods of using the salts . also disclosed are 3 - and 3 -- 9 - naphthyridin - 2 - yl )- nonanoic acid in the form of a zwitterion trihydrate .