What defines Level A IVIVC in formulation development?

• A. A Level A IVIVC is a regression line fit to in vitro data only.
• B. A Level A IVIVC is a point-to-point correlation between in vitro dissolution and in vivo plasma concentration profiles, enabling reliable prediction.
• C. Level A applies only to dissolution testing.
• D. Level A IVIVC does not require in vivo data.

Answer: (B)

Level A IVIVC means you’ve established a direct, point-to-point link between how a formulation dissolves in vitro and how the drug appears in the bloodstream in vivo. In other words, the entire in vivo plasma concentration-time profile can be predicted from the dissolution data using a time-matched correlation. This requires paired in vitro and in vivo data to define the relationship, and it provides reliable prediction of in vivo performance from dissolution testing alone, which is especially valuable for regulatory decisions and biowaivers for certain immediate-release products.

The other statements don’t fit Level A because it isn’t just a regression of in vitro data by itself, it isn’t limited to dissolution testing, and it does require in vivo data to establish the predictive link.