chapter  3
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II. The Biopharmaceutics Classification System

This guidance provides recommendations for sponsors of investigational new drug applications (INDs), new drug applications (NDAs), abbreviated new drug applications (ANDAs), and supplements to these applications that wish to request a waiver of

in vivo

bioavailability (BA) or bioequivalence (BE) studies for immediate release (IR) solid oral dosage forms. These waivers apply to:

1. Subsequent

in vivo

BA or BE studies of formulations after the initial establishment of the

in vivo

BA of IR dosage forms during the IND period

In vivo

BE studies of IR dosage forms in ANDAs

Regulations at 21 CFR Part 320 address the requirements for bioavailability (BA) and BE data for approval of drug applications and supplemental applications. Provision for waivers of

in vivo

BA/BE studies (biowaivers) under certain conditions is provided at 21 CFR 320.22. This guidance explains when biowaivers can be requested for IR solid oral dosage forms based on an approach termed the Biopharmaceutics Classification System (BCS).