In Vitro-In Vivo Correlation
Also known as: IVIVC
IVIVC is a mathematical relationship between in vitro and in vivo properties of a drug, developed to predict oral bioavailability from dissolution data. Introduced by Amidon and colleagues in the 1995 Biopharmaceutics Classification System, it bridges laboratory measurements and clinical outcomes to streamline drug development.
Key highlights
- Reduces cost and time for bioequivalence studies by predicting in vivo outcome from in vitro data
- Enables formulation optimization without repeated human trials, supporting regulatory biowaivers
- Provides early-stage decision support in development and post-approval manufacturing changes
- Well-established regulatory framework (FDA, EMA guidance) with clear acceptance criteria
Intuition
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How it works
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When to use it
Use IVIVC when developing oral solid dosage forms to reduce reliance on clinical bioavailability studies. It is mandatory for biowaiver applications and most appropriate when dissolution is the rate-limiting step in absorption. Less useful if absorption is limited by permeability rather than dissolution.
Strengths & limitations
- Reduces cost and time for bioequivalence studies by predicting in vivo outcome from in vitro data
- Enables formulation optimization without repeated human trials, supporting regulatory biowaivers
- Provides early-stage decision support in development and post-approval manufacturing changes
- Well-established regulatory framework (FDA, EMA guidance) with clear acceptance criteria
- Requires careful experimental design and sufficient variability in dissolution profiles to establish meaningful relationship
- May not apply to drugs with complex absorption mechanisms (permeability-limited, fed-state sensitivity)
- Level A correlations are difficult to establish; many methods achieve only Level B or C
- Does not account for inherent drug properties (solubility, stability) outside dissolution scope
Common pitfalls
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Applications
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Frequently asked
What is the difference between Level A, B, and C IVIVC?
Level A is a point-to-point correlation with no averaging; it is the strongest and most predictive. Level B correlates mean in vitro dissolution with mean in vivo data. Level C is a single-point correlation (e.g., AUC to dissolution at 30 minutes). Level A and B require robust data; Level C is less rigorous but still acceptable for certain changes.
Can IVIVC replace clinical bioavailability studies entirely?
A strong Level A IVIVC can support a biowaiver to avoid repeat clinical studies for minor formulation changes. However, initial clinical studies are still required to establish the correlation. Once established and regulatory-approved, IVIVC can reduce or eliminate future trials.
What data do I need to build an IVIVC?
You need in vitro dissolution data (using USP apparatus with multiple time points) and corresponding in vivo PK data (AUC, Cmax from human or animal studies) for at least 3–4 formulations spanning a range of dissolution rates. More data points strengthen the model.
Why does IVIVC sometimes fail to predict outcomes?
IVIVC assumes dissolution is the rate-limiting step. If the drug is permeability-limited, food effects dominate, or pH variability in the GI tract is critical, the in vitro–in vivo relationship may not hold. Always verify the underlying assumptions.
Sources
- 1.Amidon, G. L., Lennernäs, H., Shah, V. P., & Crison, J. R. (1995). A theoretical basis for a biopharmaceutic drug classification: the correlation of in vitro drug product dissolution and in vivo bioavailability. Pharmaceutical Research, 12(3), 413-420.
- 2.Shah, V. P., Amidon, G. L., & Levy, G. (1996). Level A, B, and C strategic approaches for biopharmaceutical classification-based dissolution specifications and in vitro-in vivo correlations. Pharmaceutical Research, 13(12), 1799-1801.
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Cite this page
ScholarGate. (2026, June 3). In Vitro-In Vivo Correlation. ScholarGate. https://scholargate.app/pharmacology/in-vitro-in-vivo-correlation