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# Allergan Wants More Changes in Cyclosporine Guidance
- URL: https://www.fdaweb.com/allergan-wants-more-changes-in-cyclosporine-guidance/
- Published: 2016-04-19T12:00:00.000Z
- Updated: 2026-09-14T20:55:46.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5135416

> Allergan says that a revised FDA draft guidance on cyclosporine has improved, in certain important aspects, the scientific rigor of analyses suggested in the earlier version, but still leaves open some “fundamental gaps that prevent the 2016 draft guidance from describing *in vitro* analyses that could be adequate on their own to allow FDA to judge whether a proposed generic cyclosporine ophthalmic emulsion is bioequivalent to Restasis.” The firm’s 4/18 [comment letter](https://www.regulations.gov/contentStreamer?documentId=FDA-2007-D-0369-0381&attachmentNumber=1&disposition=attachment&contentType=pdf&ref=fdaweb.com) says the revised draft does not address the basic problem with relying on *in vitro* analyses to establish bioequivalence to Restasis, which is that to date no *in vitro* analyses for the product have been validated as a proxy for *in vivo* bioavailability.  
>  
> The letter asks that the agency address *in vitro* release method, methodology to assess globule sizes, drug distribution in different phases of the emulsion, the lack of stated ranges for other analytical parameters, evaluation of multiple products and replicates, and the notion that non-biological complex drugs require more thorough analysis to evaluate bioequivalence.