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# Impax Petitions for Tighter Generic Bioequivalence for Rytary
- URL: https://www.fdaweb.com/impax-petitions-for-tighter-generic-bioequivalence-for-rytary/
- Published: 2017-02-02T12:00:00.000Z
- Updated: 2026-09-14T22:04:22.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5137892

Impax Laboratories has filed a [petition](https://www.regulations.gov/document?D=FDA-2017-P-0662-0001&ref=fdaweb.com) urging FDA to refuse to receive or approve any ANDA seeking approval to market a generic version of Rytary (carbidopa and levodopa) extended-release capsules unless the generic drug applicant has demonstrated bioequivalence to Rytary through scientifically appropriate methods outlined in the document. The tighter bioequivalence is necessary, Impax contends, because of the “unique pharmacokinetic profile of Rytary.” It says “bioequivalence metrics that are sensitive to the overall PK profile and predictive of the desired clinical outcomes are necessary to ensure that proposed generic formulations... are bioequivalent to Rytary.”