When you take a generic pill, you expect it to work just like the brand-name version. That’s where IVIVC, In Vitro-In Vivo Correlation, a scientific method that links lab-based drug release tests to how the drug behaves in the human body. Also known as in vitro-in vivo relationship, it’s the bridge between what happens in a test tube and what happens inside your bloodstream. Without IVIVC, there’s no reliable way to prove a generic drug will deliver the same results as the original—no matter how similar the ingredients look on paper.
IVIVC isn’t just a technical term for scientists. It’s a requirement for FDA approval of many generic drugs. When a company wants to sell a cheaper version of a medicine, they must show their version releases the active ingredient at the same rate and amount as the brand drug. That’s done through bioavailability studies, tests that measure how quickly and how much of the drug enters the bloodstream. These studies rely on IVIVC to avoid testing every single batch on real people. Instead, they use controlled lab conditions—like dissolving the pill in simulated stomach fluid—to predict how it will behave in your body. This saves time, money, and reduces the need for human trials.
IVIVC also helps explain why some generic drugs work better than others. Not all manufacturers use the same excipients (inactive ingredients) or manufacturing methods. Even small differences in how a pill breaks down can change how fast the drug gets absorbed. That’s why pharmacokinetics, the science of how drugs move through the body over time matters so much. A drug might dissolve perfectly in a lab test but get stuck in your gut if the coating isn’t right. IVIVC catches those hidden flaws before the medicine ever reaches your medicine cabinet.
It’s not just about generics. IVIVC plays a role in new drug development too. If a company is tweaking a formula to make it easier to swallow or longer-lasting, IVIVC helps them predict the impact without running endless clinical trials. It’s the fastest way to know if a change actually works—or if it’s just a placebo in disguise.
You won’t see IVIVC listed on your prescription, but it’s working behind the scenes every time you pick up a generic. It’s why your pharmacist can confidently swap one pill for another. And it’s why regulators won’t approve a generic unless they’re sure it won’t just look the same—it will act the same. The posts below dig into how this science connects to real-world issues: why some generics cost less overseas, how bioequivalence studies are done, and what happens when the correlation breaks down.
Dec, 2 2025
IVIVC lets pharmaceutical companies replace costly human bioequivalence trials with lab-based dissolution tests. Learn how this science works, why most submissions fail, and when it’s the right choice for generic drug approval.