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# Biopharmaceutics Classification Biowaivers Guidance
- URL: https://www.fdaweb.com/biopharmaceutics-classification-biowaivers-guidance/
- Published: 2021-05-11T12:00:00.000Z
- Updated: 2026-09-14T16:58:27.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5149288

FDA has published an International Council for Harmonization guidance, *M9 Biopharmaceutics Classification System-Based Biowaivers*, describing the biopharmaceutics classification system (BCS)-based biowaivers approach intended to reduce the need for *in vivo* bioequivalence studies. The [document](https://www.fda.gov/media/148472/download?ref=fdaweb.com) says *in vivo* bioequivalence studies may be exempted if an assumption of equivalence in *in vivo* performance can be justified by satisfactory *in vitro* data.

The guidance says the BCS is a scientific approach based on the aqueous solubility and intestinal permeability characteristics of the drug substance or substances.