This study is a randomized, open-label, crossover study to assess the bioequivalence of 1 risedronate 150 mg tablet versus 2 risedronate 75 mg tablets administered as a single oral dose. Approximately 320 subjects will be enrolled from 4 study centers in the U.S.

The data to support the interchangeability of one risedronate 150 mg tablet versus two risedronate 75 mg tablets as monthly dose forms is primarily based on the similarity of in vitro dissolution and an in vivo study, which showed risedronate absorption is not dissolution rate limited. These results suggest that monthly dosing of risedronate may be accomplished by administration of either one risedronate 150 mg tablet or two risedronate 75 mg tablets. The purpose of this study is to provide additional clinical data to support the interchangeability of these 2 dose regimens.

• Experimental: One risedronate 150 mg tablet administered orally after an overnight (10 hour) fast, followed by a 4 hour post-dose fast
• Active Comparator: Two risedronate 75 mg tablets administered as a single oral dose after an overnight (10 hour) fast, followed by a 4 hour post-dose fast

Inclusion Criteria:

• be in good general health based on medical history, physical examination, and laboratory evaluation
• have a body mass index (BMI) ≤ 32 kg/m2 at screening

Exclusion Criteria:

• has clinically significant uncontrolled cardiovascular, hepatic, renal, or thyroid disease
• has any disease or surgery known to alter normal GI structure or function
• has a creatinine clearance of < 60 mL/min, estimated by serum creatinine using the Cockcroft-Gault formula