FIELD: organic chemistry, chemical technology, medicine, pharmacy.
SUBSTANCE: invention relates to a new method for preparing 3-pyridyl-1-hydroxyethylidene-1,1-bisphosphonic acid sodium salt semipentahydrate and monohydrate (A) that involves the following stages: (a) preparing an aqueous solution of compound (A); (b) heating an aqueous solution to temperature from about 45oC to about 75oC; (c) addition of solvent to an aqueous solution of compound (A) being solvent is taken among the group including alcohols, esters and ethers, ketones, amides and nitriles; and (d) optional cooling an aqueous solution. This method allows preparing hydrate forms of compound (A) that differ from anhydrous form by both solubility and by bioavailability and can be used in pharmaceutical compositions for treatment of osseous diseases and disturbances in calcium metabolism.
EFFECT: improved preparing method.
10 cl, 1 tbl, 2 ex
