Читать книгу Physiologically Based Pharmacokinetic (PBPK) Modeling and Simulations - Sheila Annie Peters - Страница 24

The hepatic extraction ratio of a drug is obtained by taking Q_LI to the left‐hand side in Equation 1.26

(1.28)

For high CL_int compounds, the displacement of the drug from plasma proteins is rapid and equilibrium cannot be established between concentrations of the bound and unbound drug in blood (C_b, C_u,b ) and in liver (C_u,liver ). This can be represented as:

For low CL_int compounds, there is equilibrium between the bound drug and unbound drug in blood and liver and only the C_u,liver is available to the drug metabolizing enzymes. The equilibrium between the different drug concentrations is shown below: