Basic Pharmacokinetics Clinical Pharmacy Department IV bolus/ Urinary Data College of Pharmacy PHCL 461 Homework III Students Name: . ID: .. NOTE: Answer ALL of the following questions; Make your calculation in the same tables below. 1. T. M. 70 kg female patient received IV injection of drug X. A urine samples have been collected as follows: Time Interval (hr) Amount of drug in urine. (mg) 0  1 9.7 1  2 6.7 2  4 6.2 4  6 3.4 6  9 1.5 9 - 12 0.63 Using the Rate method, determine the following: a. The half-life for drug X. b. Elimination rate constant kd c. Renal elimination rate constant ke c. Fraction of the drug excreted unchanged renally Homework III 1 PHCL 461 Basic Pharmacokinetics 2. The following data was obtained from a patient received IV bolus of dioxin 1 mg. Collection Time (hr) Urine Volume (mL) Conc. of digoxin in urine (mg/mL) Plasma conc. of digoxin at T(midpoint) 1 1000 0.225 1.6 2 1200 0.123 1.04 3 1400 0.068 0.68 4 1100 0.056 0.44 5 1300 0.031 0.29 7 2500 0.017 0.15 a. Graphically, determine the half-life of digoxin. b. Calculate the amount of digoxin remains in the body after four days. c. Calculate the Renal clearance CLR and the total body clearance CL of digoxin. d. Assuming that digoxin is only eliminated through kidney and liver. Calculate Km Homework III 2 PHCL 461 Basic Pharmacokinetics 3. Calculate the half life for Methotrexate in a patient weighting 70 kg, the volume of distribution of the drug is 0.4 L/kg and the renal clearance CLr is 3 L/hr, assuming 95% of the drug is eliminated in the urine unchanged (unmetabolized). 4. The half life of Penicillin in adult healthy patients is 30 minutes, the renal clearance Clr is 275 mL/min and its elimination is 90% through the kidney unmetabolized. What is the apparent volume of distribution for penicillin? Homework III 3 PHCL 461