| abstract |
A process for the preparation of 3-pyridil-1-hydroxyethyliden-1,1-biphosphonic acid monosodium salt of formula n nin an amorphous form, preferably lyophilized, and its pharmaceutical compositions are described. Said amorphous form, characterized by stability and simplicity of preparation and formulation, can be obtained by an industrially applicable lyophilization process, which comprises the steps of: a) dissolving or suspending 3-pyridyl-1-hydroxyethyliden-1,1-biphosphonic acid in an aqueous solvent, b) adding one equivalent of a base having sodium as cation c) subjecting the solution to lyophilization |