In vitro disintegration studies of weekly generic alendronate sodium tablets (70 mg) available in the US

ABSTRACT

Background: Bisphosphonates as a class have the potential to cause upper gastrointestinal irritation. Although the generic alendronate sodium tablets are bioequivalent to the branded product, a potential concern is that the pharmaceutical attributes of the various generic formulations my affect the potential for local irritation and tolerability.

Scope: The in vitro disintegration times were determined using the method described in the US Pharmacopeia 30 (USP 30). The disintegration of three generic alendronate sodium tablets 70 mg available in the United States was compared to that of the branded product.

Findings: The mean disintegration times of the generic alendronate sodium tablets ranged from 9 to 10 s for the Barr lots to 108 s for the Watson lot. The disintegration time of the branded product (Fosamax®) was 53 s. The three Barr lots and one Teva lot had rapid disintegration times which were similar to the disintegration standards (< 30 s) for orally disintegrating tablets. Since there is no established disintegration time for alendronate sodium tablets there can be no assurance that the generic tablets are equivalent to the branded product in terms of esophageal exposure. However, the in vitro disintegration times have not been correlated with in vivo disintegration performance.

Conclusions: Copies of generic alendronate sodium tablets are approved based on the results of single-dose bioavailability studies in healthy subjects and this is not considered adequate to establish similar disintegration characteristics.

Key words: :

• Alendronate sodium tablets
• Disintegration time
• United States copies/generics

Acknowledgment

Declaration of interest: This study was supported by Procter & Gamble Pharmaceuticals, Cincinnati, OH, USA and Sanofi-Aventis, Paris, France. A. C. P. is a paid consultant for Procter & Gamble.