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# Guide on Drug Biopharmaceutics Classification
- URL: https://www.fdaweb.com/guide-on-drug-biopharmaceutics-classification/
- Published: 2021-05-13T12:00:00.000Z
- Updated: 2026-09-14T16:58:53.000Z
- Author: David McFarland
- Tags: FDA Policy/General, #legacy-id-D5149311

*Federal Register* notice: FDA has made available a final guidance entitled *M9 Biopharmaceutics Classification System-Based Biowaivers*. The document provides recommendations to support the biopharmaceutics classification of drug substances and the Biopharmaceutics Classification System-based waiver of the in vivo bioequivalence (BE) study requirement for certain drug products. It is also intended to avoid or reduce the need for human BE trials based on extensive in vitro characterization of the drug substance and drug product properties. The guidance replaces the existing FDA guidance issued 12/26/2017 entitled *Waiver of In Vivo Bioavailability and Bioequivalence Studies for Immediate-Release Solid Oral Dosage Forms Based on a Biopharmaceutics Classification System*. To view the notice, click [here](https://www.govinfo.gov/content/pkg/FR-2021-05-12/pdf/2021-09962.pdf?ref=fdaweb.com).