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# Salix Wants Restrictions on Xifaxan ANDAs
- URL: https://www.fdaweb.com/salix-wants-restrictions-on-xifaxan-andas/
- Published: 2016-10-27T12:00:00.000Z
- Updated: 2026-09-14T21:43:09.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5137195

Salix Pharmaceuticals is petitioning FDA not to approve an ANDA citing any strength of its Xifaxan (rifaximin) as the reference-listed drug unless it conforms with an extensive series of conditions submitted by Salix. The company [says](https://www.regulations.gov/contentStreamer?documentId=FDA-2016-P-3418-0001&attachmentNumber=1&disposition=attachment&contentType=pdf&ref=fdaweb.com) that any ANDA that references either strength or any indication of Xifaxan as the reference-listed drug should meet these criteria: characterization studies demonstrating that the proposed generic’s active ingredient is identical in rifaximin polymorph profile to that of the Xifaxan active ingredient ,and specified bioequivalence and *in vitro* dissolution tests with outcomes specified by Salix.

The company also asks that FDA revise its draft guidance on rifaximin to incorporate its criteria at a minimum.