Problems related to Clearance

Problem 01. Arterial plasma entering the liver contains 19 mg/L of a new drug being investigated. Venous blood contains 10 mg/L. Plasma flow to the liver is 0.4 liter per hour.

1. What is the extraction ratio?
2. What is the clearance rate for this organ?
3. Do you have enough information to calculate an elimination rate constant?

Problem 02. Renal extraction ratio of a drug is 0.3 and the Cl(R) = 0.2 L/h/Kg.

1. How much mass of drug is eliminated during an hour in which the average concentration is 20 mg/L in a 1 Kg animal?
2. Will the same amount be eliminated during the subsequent hour?

Problem 03. Renal Clearance of a drug is 2 L/h. Hepatic Clearance is 1 L/h. No other organs eliminate significant amounts of this drug.

1. What is the total body clearance of this drug?
2. How would one express this concept in typical mathematical symbols?

Problem 04. Given: CL(body) = 10 L/hr/Kg; Vd= 70 L/Kg

1. What fraction of the Vd is "freed" of drug per hour?
2. How does this correspond to the elimination rate constant, Ke?

Problem 05. The Ke of a drug is 0.1/h. The Vd is 0.4 L/Kg.

1. What is the CL?