present invention can be made using the synthetic methods disclosed in japanese patent 80 98 193 jul 25 1980 to nissan kygaku kagyo k k japanese patent 80 98 105 jul 25 1980 to nissan chemical industries west german patent 2 831 578 feb 1 1979 to fumio and w ploger et al z anorg allg chem 389 119 1972 the disclosures of which are incorporated herein by reference the aminoethane diphosphonic acid compounds however are best prepared as follows the term 34 risedronate 34 as used herein denotes the diphosphonate compound 3 pyridyl 1 hydroxyethylidene 1 1 bisphosphonic acid and has the following structure str6 the compound risedronate is further described in the following publications all hereby incorporated by reference herein epo patent application 0 186 405 of benedict et al assigned to the procter amp gamble co published jul 2 1986 and 34 an international conference bisphosphonates current status and future prospects the royal college of physicians london england may 21 22 1990 organized by ibc technical services the term 34 risedronate active ingredient 34 includes risedronate risedronate salts and risedronate esters or any mixture thereof any pharmaceutically acceptable non toxic salt or ester of risedronate may be used as the risedronate active ingredient in the novel oral dosage forms of the present invention the salts of risedronate may be acid addition salts in particular the hydrochloride but any pharmaceutically acceptable non toxic organic or inorganic acid salt may be used in addition salts formed with the carboxylic acid group may be used in addition salts formed with the carboxylic acid group may be used including but not limited to alkali metal salts k na and alkaline earth metal salts ca mg the ca and.