21 CFR Part 312 · Investigational New Drug Application

21 CFR 312.3

Definitions and interpretations

21 CFR 312.3 is the regulation titled “Definitions and interpretations” in 21 CFR Part 312, Investigational New Drug Application. Since 2021, 5 FDA warning letters have cited it.

Letters citing it
5 since 2021
Jan 1 to Oct 30, 2026
1 against 0 on the same dates in 2025
Most often cited with
21 CFR 312.2, in 4 letters
Closed out
0% of these letters have a published close-out
See the 5 letters citing 21 CFR 312.3 →

Letters citing it, by year issued

All are drug letters. 2026 runs to Oct 30, 2026. Pick a year to see its letters.

  1. 22021
  2. 02022
  3. 12023
  4. 02024
  5. 12025
  6. 12026

The regulation

Read the text of 21 CFR 312.3 (eCFR, as of Sep 1, 2026)

(a) The definitions and interpretations of terms contained in section 201 of the Act apply to those terms when used in this part:

(b) The following definitions of terms also apply to this part:

Act means the Federal Food, Drug, and Cosmetic Act (secs. 201-902, 52 Stat. 1040 et seq., as amended (21 U.S.C. 301-392)).

Clinical investigation means any experiment in which a drug is administered or dispensed to, or used involving, one or more human subjects. For the purposes of this part, an experiment is any use of a drug except for the use of a marketed drug in the course of medical practice.

Contract research organization means a person that assumes, as an independent contractor with the sponsor, one or more of the obligations of a sponsor, e.g., design of a protocol, selection or monitoring of investigations, evaluation of reports, and preparation of materials to be submitted to the Food and Drug Administration.

FDA means the Food and Drug Administration.

IND means an investigational new drug application. For purposes of this part, “IND” is synonymous with “Notice of Claimed Investigational Exemption for a New Drug.”

Independent ethics committee (IEC) means a review panel that is responsible for ensuring the protection of the rights, safety, and well-being of human subjects involved in a clinical investigation and is adequately constituted to provide assurance of that protection. An institutional review board (IRB), as defined in § 56.102(g) of this chapter and subject to the requirements of part 56 of this chapter, is one type of IEC.

Investigational new drug means a new drug or biological drug that is used in a clinical investigation. The term also includes a biological product that is used in vitro for diagnostic purposes. The terms “investigational drug” and “investigational new drug” are deemed to be synonymous for purposes of this part.

Investigator means an individual who actually conducts a clinical investigation (i.e., under whose immediate direction the drug is administered or dispensed to a subject). In the event an investigation is conducted by a team of individuals, the investigator is the responsible leader of the team. “Subinvestigator” includes any other individual member of that team.

Marketing application means an application for a new drug submitted under section 505(b) of the act or a biologics license application for a biological product submitted under the Public Health Service Act.

Sponsor means a person who takes responsibility for and initiates a clinical investigation. The sponsor may be an individual or pharmaceutical company, governmental agency, academic institution, private organization, or other organization. The sponsor does not actually conduct the investigation unless the sponsor is a sponsor-investigator. A person other than an individual that uses one or more of its own employees to conduct an investigation that it has initiated is a sponsor, not a sponsor-investigator, and the employees are investigators.

Sponsor-Investigator means an individual who both initiates and conducts an investigation, and under whose immediate direction the investigational drug is administered or dispensed. The term does not include any person other than an individual. The requirements applicable to a sponsor-investigator under this part include both those applicable to an investigator and a sponsor.

Subject means a human who participates in an investigation, either as a recipient of the investigational new drug or as a control. A subject may be a healthy human or a patient with a disease.

[52 FR 8831, Mar. 19, 1987, as amended at 64 FR 401, Jan. 5, 1999; 64 FR 56449, Oct. 20, 1999; 73 FR 22815, Apr. 28, 2008]

Text from eCFR as of Sep 1, 2026.

Cited alongside it

Regulations that appear in the same letters as 21 CFR 312.3.

Latest letters citing it

The 3 letters citing 21 CFR 312.3 that FDA posted most recently.

See the 5 letters citing 21 CFR 312.3 →
For regulated teams

Put this kind of reading to
work on your own records.

Botable builds and runs a custom AI layer around the software you already use, so your team can do the job you hired them for.

Counts include every citation in a letter, as the Letters filter does. How this database is built.

Every letter by dateHow this database is built

FDA Warning Letter Alerts

Share this view

Send the same filters, search and view to a colleague.

You choose what to post or send. Sharing a link does not change access to this site.