---
kind: "section"
citation: "21 C.F.R. § 320.35"
title: "21"
number: "320.35"
heading: "Requirements for in vitro testing of each batch."
url: "https://uscodex.org/cfr/21/320.35"
---

# §320.35. Requirements for in vitro testing of each batch.


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.


## Notes

### Amendments

[42 FR 1635, Jan. 7, 1977. Redesignated at 57 FR 18001, Apr. 28, 1992]

### Source

Source: 42 FR 1648, Jan. 7, 1977, unless otherwise noted.

### Authority

Authority: 21 U.S.C. 321, 351, 352, 355, 371.

### Amendments

[42 FR 1635, Jan. 7, 1977. Redesignated at 57 FR 18001, Apr. 28, 1992]