# Homework 5 - Due Oct 9

You may work in groups, but the homework must be done individually.

- Estimate the half-life of the drug illustrated in Figure 13.1B in Box 13.1.
- Plot (in Excel or Matlab) the predicted plasma concentration of a 500 mg aspirin tablet from 0 to 24 h if a patient takes an aspirin at t = 0, 4, and 8 hours. Assume a half-life of 3 hours and a plasma volume of 3 L.
- Norplant is an implantable drug-delivery system for contraception. The original Norplant system consisted of six reservoirs, each containing 36 mg of levonorgesteral that was released at a constant rate for five years. What is the average release rate of the drug into the body per day?
A 5 g IV injection of antibiotic is administered to a human with a plasma volume of 3 L. The antibiotic has a half-life of 2.5 hr in the plasma.

a. Determine the elimination rate constant, \(k\).

b. Plot (in Excel or Matlab) the concentration of the antibiotic in the plasma from the time of a single injection to 24 hr.

c. If the concentration of the antibiotic is not to fall below^{1}⁄_{3}of the initial dosage, when should a second injection be administered?