Equation 17.2.1 Hepatic Clearance according to the Well Stirred Model
Equation 17.2.2 Hepatic Clearance according to the Parallel Tube Model
|Parameter||Example Value||Range of Values||Comment|
|F*Dose||100 mg||100 mg ±||Linear system in this example|
|Absorption Rate Constant||1.5 hr-1||0.1 - 10.0 hr-1|
|Volume of Distribution
|20 L||7 - 200+ L|
|Excretion Rate Constant
|0.05 hr-1||0 - 5+ hr-1||Non hepatic excretion/elimination|
|Unbound Intrinsic Clearance
|10 L/hr||0 - 1500+ L/hr||Shargel and Yu, 3rd, 1993|
|Hepatic Blood Flow
|80 L/hr||60-120 L/hr||70 Kg adult, Shargel and Yu, 3rd, 1993|
|Fraction unbound, in blood
|0.5||0 - 1|
Equations used in this simple pharmacokinetic model.
Equation 17.2.3 Elimination Rate Constant as a function of CLH, V and ke
Equation 17.2.4 Concencentration versus Time after a single Oral Dose
Equation 17.2.5 Extraction Ratio calculated from CLH and QH
Explore flow limited drug behavior by setting CLint somewhat larger (> 200 L/hr) than the hepatic blood flow rate. Change QH, fu and CLint to see which parameters have the greatest influence of half-life and AUC. Capacity limited drug behavior can be explored by setting CLint to a lower value (< 40 L/hr). Explore the effect of V on drug half-life.
Explore the equation by changing the parameter(s). Add additional lines with different parameter values using the Add Line button.