Practice Problems Biopharmaceutics-I

Problem 1 Using the equation C = C0e-Kt, determine the plasma concentration of a drug 24 hours after a peak level of 10 mg/L is observed if the elimination rate constant is 0.05 hr-1. A. 3.01 mg/L B. 33.2 mg/L C. 18.1 mg/L

Problem 2 Which of the following is a proper unit for the elimination rate constant? A. minutes B. mg/minute C. hr-1 D. mg/L

Problem 3 If the elimination rate constant is 0.2 hr-1 the percent of drug removed per hour is: A. 20%. B. 1%. C. 0.1%. D. 10%.

Problem 4 If the plasma concentration just after a gentamicin dose is 10 mg/L and the patient's elimination rate constant is 0.15 hr-1, predict what the plasma concentration will be 8 hours later. A. 6.0 mg/L B. 3.0 mg/L C. 1.5 mg/L D. 1.0 mg/L

Problem 5 For a drug that has an initial plasma concentration of 120 mg/L and a half-life of 3 hours, what would the plasma concentration be 12 hours after the initial concentration? A. 15 mg/L B. 112.5 C. 7.5 mg/L D. 60

Problem 6 If a drug has an elimination rate constant of 0.564 hr-1, what is the half-life? A. 1.23 hours B. 0.81 hour C. 1.77 hours

Problem 7 From 1 M HCl stock solution, how will you make 10 ml of 0.1 M solution?

Problem 8 You have 50 ml of 50 mg/ml stock solution of a vaccine which is very expensive. You have 5 ml and 10 ml volumetric flasks available in your lab. Show the calculation for preparation of 45, 40, 35, 30, 25, 20, 15, 10, 5 mg/ml solution of the vaccine using both 5 ml and 10 ml volumetric flasks. Design a table for the process showing the volume to be added in each flask. You just require 2 ml sample of each concentration for your analysis. Which volumetric flasks will you choose to use and why? Explain with calculations.