Final answer:
In the context of weakly basic drugs, Papp is the apparent permeability coefficient that measures how easily a drug can cross biological membranes. The Papp value is determined through experiments using a Caco-2 monolayer. This information is essential for evaluating the absorptive potential of a drug.
Step-by-step explanation:
In the context of weakly basic drugs, the significance of Papp is its role in determining the permeability of a drug across biological membranes. Papp stands for the apparent permeability coefficient, which is a measure of how easily a drug can cross a membrane. A higher Papp value indicates greater permeability, meaning the drug can more readily enter and exit cells.
In this case, Papp is determined through experiments using a Caco-2 monolayer, which is a model of intestinal epithelium. By quantifying drug transport in both the apical to basolateral and basolateral to apical directions, the Papp value for a drug can be determined. This information is important for evaluating the absorptive potential of a drug and its likelihood to be efficiently transported across biological barriers.