The purpose of an Institutional Review Board (IRB) is to assess research proposals in terms of the ethical use of human subjects. The legal foundation for the IRB-s was established by the National Research Act in 1974 (21CFR56).
The Nuremberg Code was created in 1947, after the Nuremberg Trials on the Nazi Experiments during WWII. Here is the full text of The Numerberg Code. The main guidelines regarding research include voluntarily participation, informed consent, aim at positive results and avoid risk or unnecessary suffering, and that research must be based on previous knowledge and led by qualified staff.
Created in 1978, after the Tuskegee Syphilis Study (1932-1972), the Belmont Report remains a primary ethical framework for researchers today. The ethical research must assure: respect for Persons, beneficence, and justice. Here is the full text of The Belmont Report.
New emerging technologies called for a major update to the Federal Regulations regarding research and the IRB process. Numerous amendments to the existing regulations, known as the "Common Rule", were widely discussed under the auspices of OHRP (Office for Human Research Protections) since 2011. Main revisions were published in January 2017 (the "Revised Common Rule"). The final product of the deliberation is, so called, the Final Rule, which was enacted by Congress on January 21, 2019.
The updated Final Rule is published at Text of the Final Common Rule or Electronic Code of Federal Regulations. Title 45 PART 46—Protection of Human Subjects. (In our opinion, the second link offers more convenient navigation.)
Grady C. Institutional Review Boards: Purpose and Challenges. Chest. 2015;148(5):1148–1155. doi:10.1378/chest.15-0706
Rajab MH, Alkawi MZ, Gazal AM, Alshehri FA, Shaibah HS, Holmes LD. Evaluation of a University's Institutional Review Board Based on Campus Feedback: A Cross-Sectional Study. Cureus. 2019;11(10):e5829. Published 2019 Oct 3. doi:10.7759/cureus.5829