PHAR 4634 Pharmaceutics III

Chapter 5

Homework Assignment - 1995 #2

1. Assume that a one compartment pharmacokinetic model applies. Calculate the cumulative amount of unchanged drug excreted into urine up to the times 1, 2, 4, 6, 9, and 12 hours after a 500 mg i.v. bolus dose. Use kel = 0.125 hr-1; V = 18.4 L; and fe = 0.60.

Answer

2. Given the data in Table 1, below, calculate kel, ke, and fe. Assume a linear one compartment model.

Table 1. Volume and Concentration of Unchanged Drug found in Urine after an i.v. Bolus Dose of 400 mg.
Time Interval (hr) Volume of Urine Excreted (ml) Concentration in Urine (g/ml) <------> <------> <------>
0-1 65 480


1-2 64 390


2-4 121 315


4-6 130 205


6-9 no sample



9-12 175 75


12-24 750 25


Answer

3. A given drug follows linear one compartment pharmacokinetics. If the values of kel and fe in patients with normal renal function are 0.18 hr-1 and 0.75, respectively, calculate the kel in a patient with 1/5th normal renal function. Assume that the non-renal rate processes do not change.

Answer