{"data":{"id":"us/21-cfr-320.28","jurisdiction":"us","citation":"21 CFR 320.28","heading":"Correlation of bioavailability with an acute pharmacological effect or clinical evidence.","body":"Correlation of in vivo bioavailability data with an acute pharmacological effect or clinical evidence of safety and effectiveness may be required if needed to establish the clinical significance of a special claim, e.g., in the case of an extended release preparation.","path":["Title 21—Food and Drugs","CHAPTER I—FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES","SUBCHAPTER D—DRUGS FOR HUMAN USE","PART 320—BIOAVAILABILITY AND BIOEQUIVALENCE REQUIREMENTS","Subpart B—Procedures for Determining the Bioavailability or Bioequivalence of Drug Products"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-21.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:47Z","sha256":"cde33763604a97234ecbc39abe6163ab37d586250c58ab6f1a840ff214349e07","source_id":"us-cfr","stale":true,"prev":"us/21-cfr-320.27","next":"us/21-cfr-320.29"},"notice":"GroundRules: Original legal text. Not legal advice."}