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# Tissueblue Regulatory Review Determined
- URL: https://www.fdaweb.com/tissueblue-regulatory-review-determined/
- Published: 2022-11-10T12:00:00.000Z
- Updated: 2026-09-14T18:06:01.000Z
- Author: David McFarland
- Tags: FDA Policy/General, #legacy-id-D5153176

*Federal Register* notice: FDA has determined for patent extension purposes the regulatory review period for Dutch Ophthalmic’s Tissueblue (brilliant blue g ophthalmic solution), a disclosing agent indicated to selectively stain the internal limiting membrane. The regulatory review period is 4,631 days, of which 4,395 days occurred during the testing phase and 236 days during the approval phase. To view the notice, click [here](https://www.govinfo.gov/content/pkg/FR-2022-11-09/pdf/2022-24434.pdf?ref=fdaweb.com).