part_subject: "BIOAVAILABILITY AND BIOEQUIVALENCE REQUIREMENTS"
subpart_code: "B"
subpart_subject: "Procedures for Determining the Bioavailability or Bioequivalence of Drug Products"
section_number: "320.35"
section_subject: "Requirements for in vitro testing of each batch."
cfr_reference: "21 CFR 320.35"
title_name: "Title 21"
title_subject: "Food and Drugs"
parts_covered: "Parts 300 to 499"
revised_date: "Revised as of April 1, 2019"
publication_date: "As of April 1, 2019"
contains_description: "Containing a codification of documents of general applicability and future effect"
publication_info: "Published by the Office of the Federal Register National Archives and Records Administration as a Special Edition of the Federal Register"
---
If a bioequivalence requirement specifies a currently available in vitro test or an in vitro bioequivalence standard comparing the drug product to a reference standard, the manufacturer shall conduct the test on a sample of each batch of the drug product to assure batch-to-batch uniformity.