The Hatch-Waxman Act of 1984 created an FDA pathway for generic drugs requiring proof of bioequivalence.

“basically what that said is it created a pathway at the FDA for generic drug makers to apply for approval and said the safety and efficacy of these molecules has already been established so you don't have to reprove that you don't have to do clinical trials on thousands of people what you do need to do is prove that your drug is bio equivalent to the branded product”