| abstract |
Diphosphonate compounds, processes for their preparation and pharmaceutical compositions containing them and being useful for treating calcium metabolism disorders. The diphosphonates are of the formula <IMAGE> (I) wherein R1 and R2 are hydrogen, acyl or alkyl which can be substituted by aryl, R3 and R4 are hydrogen or alkyl or R3 and R4 together represent lower alkylene, R5 is a hydrogen atom or alkyl, X is a valency bond or alkylene, Y is a valency bond, alkylene or substituted alkylene, Z is hydrogen, hydroxyl or amino group optionally substituted by alkyl and n is 1, 2 or 3; and including the pharmacologically acceptable salts thereof. |