Theophylline is a pharmaceutical drug that is sometimes

Problem 78

Theophylline is a pharmaceutical drug that is sometimes used to help with lung function. You observe a case where the initial lab results indicate that the concentration of theophylline in a patient's body decreased from 2.0 103 M to 1.0 103 M in 24 hours. In another 12 hours the drug concentration was found to be 5.0 104 M. What is the value of the rate constant for the metabolism of this drug in the body?

                                                      Step by step solution

Step 1 of 2

From the given,

Initial concentration of theophylline

Concentration of theophylline after 24 hours

Concentration of theophylline after 12 hours

From the given data, it is clear that the half-life decreases with decrease in the concentration of the drug. Hence this is a zero order reaction.

Integrated rate law for zero order reaction -

where [ A ] is the concentration at time t   is the initial concentration

k is the rate constant.