FDA Authorization of Generics: Legal Basis and Approval Process Explained

The U.S. healthcare system runs on generics. Right now, 9 out of 10 prescriptions filled in America are for generic drugs. That’s not luck. It’s the result of a carefully designed legal and scientific process that lets safe, affordable versions of brand-name medicines reach patients quickly. But how does the FDA actually approve these drugs? And what’s the law behind it?

The Hatch-Waxman Act: The Foundation of Generic Drug Approval

Everything starts with the Drug Price Competition and Patent Term Restoration Act of 1984-better known as the Hatch-Waxman Act. This law, signed on September 24, 1984, didn’t just tweak regulations. It completely rewrote how generic drugs enter the market. Before Hatch-Waxman, companies had to repeat every single clinical trial done by the original drugmaker. That meant years of research, millions in costs, and almost no competition. The result? Prices stayed high.

Hatch-Waxman changed that by creating the Abbreviated New Drug Application, or ANDA. This pathway lets generic manufacturers skip the expensive and time-consuming animal and human trials. Instead, they prove their drug is the same as the brand-name version in every way that matters-active ingredient, strength, dosage form, and how the body absorbs it. The FDA already confirmed the brand drug was safe and effective. The generic just has to match it.

The law also created a balance. Brand-name companies got extra patent protection to make up for time lost during FDA review. Generic makers got a clear path to challenge weak patents. And if they were the first to file a generic version of a drug with an expiring patent, they got 180 days of market exclusivity. That’s why you sometimes see two generics hit the market at once-they’re racing to be first.

What the FDA Actually Requires for Approval

Just saying a generic is "the same" isn’t enough. The FDA demands proof. Here’s what every ANDA must show:

• Same active ingredient: The exact chemical compound, no variations. If the brand has 10 mg of lisinopril, the generic must have 10 mg of lisinopril.
• Identical strength and dosage form: Tablet, capsule, injection, patch-it has to match. A 20 mg tablet can’t be sold as a 10 mg liquid unless it’s a different product entirely.
• Same route of administration: If the brand is taken orally, the generic must be too. No switching from pill to injection without a new application.
• Same intended use: The generic can’t be approved for fewer conditions than the brand. If the brand treats high blood pressure and heart failure, the generic must be approved for both.
• Bioequivalence: This is the core. The generic must deliver the same amount of active drug into the bloodstream at the same rate as the brand. The FDA requires studies in 24 to 36 healthy volunteers, measuring blood levels over time. The generic’s absorption rate must fall within 80% to 125% of the brand’s. That’s not a guess-it’s a strict statistical range.
• Same quality standards: The manufacturing site must meet the same Good Manufacturing Practice (GMP) rules as the brand’s. No corners cut on purity, stability, or contamination controls.

The FDA doesn’t just look at the drug itself. They inspect every facility involved-where it’s made, packaged, tested, and stored. A single failed inspection can delay approval by months.

The ANDA Review Process: From Submission to Approval

Submitting an ANDA isn’t like sending in a form. It’s a complex, highly technical document. A complete application includes:

• Chemistry, Manufacturing, and Controls (CMC) data-how the drug is made, tested, and stabilized
• Details on all facilities used in production
• Proposed labeling that matches the brand’s exactly
• Bioequivalence study reports with full raw data
• Patent certifications-listing every patent tied to the brand drug and stating whether the generic challenges them

Once submitted, the FDA’s Office of Generic Drugs (OGD) does a filing review. If anything’s missing-a signature, a data table, a facility ID-they issue a Refuse-to-Receive (RTR) letter. No review happens until it’s fixed, and the fee must be paid again.

If it passes filing, the clock starts. Under the Generic Drug User Fee Amendments (GDUFA), the FDA must review standard ANDAs within 10 months. Priority applications-like those for drugs in shortage or first generics-get reviewed in 8 months. That’s a big jump from the old 18-month average before GDUFA started in 2012.

One of the trickiest parts? Patent challenges. If a generic company files a Paragraph IV certification-saying a patent is invalid or won’t be infringed-the brand company can sue. That triggers a 30-month stay. The FDA can’t approve the generic during that time, even if the application is perfect. Many generics get held up this way. Some companies use this to delay competition, a practice called "patent evergreening." The FDA has been pushing back with new policies to stop these delays.

Why This Matters for Patients and the System

Generic drugs aren’t just cheaper-they’re essential. The average brand-name drug costs $1,500 a month. The generic version? Often under $30. That’s not a small difference. It’s the difference between someone taking their blood pressure medicine or skipping doses because they can’t afford it.

Since Hatch-Waxman, generic drugs have saved the U.S. healthcare system more than $3.4 trillion over the last decade. In 2023 alone, the FDA approved 90 new generic drugs. Many were for high-cost conditions: cancer, diabetes, mental health. One example? The first generic version of Vivitrol, an injectable treatment for opioid addiction, approved in 2023. The FDA called it "of prime importance" given the ongoing overdose crisis.

But it’s not all smooth sailing. Complex drugs-like inhalers, topical creams, or extended-release tablets-are harder to copy. The active ingredient might be the same, but how it’s delivered can change how well it works. The FDA is now running a special initiative called "Complex Generics" to develop better testing methods for these products. Some generics still take years to get approved because the science isn’t settled.

Who Makes These Drugs? And Where?

Most of the world’s generic drugs are made overseas-mainly in India and China. But the FDA inspects every facility, no matter where it is. In 2022, the agency conducted over 3,000 inspections globally. They’ve shut down plants for poor quality control, even if the drugs were already on the market.

Major players include Teva, Sandoz, Mylan (now Viatris), and Amneal. But there’s also a growing group of smaller U.S.-based companies focused on making complex generics and filling drug shortages. In October 2025, the FDA launched a new pilot program to speed up reviews for companies that test and manufacture their generics in the United States. It’s a direct response to supply chain concerns after the pandemic.

What’s Next for Generic Drugs?

The future isn’t just about more generics-it’s about better ones. The FDA is working on:

• Standardizing testing for complex formulations like nasal sprays and transdermal patches
• Using real-world data to support approval, not just lab studies
• Improving transparency in the Orange Book, which lists patents and exclusivity periods
• Encouraging more domestic manufacturing through faster review and incentives

Biosimilars-generic versions of biologic drugs like insulin or rheumatoid arthritis treatments-are a separate pathway under the BPCIA. They’re more complex than traditional generics and take longer to approve. But they’re growing fast, and they’ll be the next big wave of cost savings.

The bottom line? The system works. It’s not perfect. Patent fights, foreign manufacturing risks, and complex drugs are still hurdles. But the FDA’s ANDA pathway has delivered safe, affordable medicine to millions. And it continues to evolve to meet new challenges-because access to medicine shouldn’t depend on how much you can pay.