Module 7. Effect of route of administration and dose form on the performance (clinical effect) of drug products.

Objectives

Having completed this exercise and based on pharmacokinetic constants and data, students should be able to:

Significance

J.F.M. Nouws et al: Comparative plasma ampicillin levels and bioavailability of five parenteral ampicillin formulations in ruminant calves.

Route of administration and dose form affect the performance (clinical effect) of drug products. Ampicillin sodium is labeled for intravenous and intramuscular use. Ampicillin trihydrate is labeled for intramuscular use only. Your choice of drugs should be based on the performance characteristics you desire in addition to the labeled route and the price of the penicillin product. This exercise demonstrates that, for Ampicillin at least, drug concentrations may be affected more by dose form than by route of administration.

When ampicillin was originally approved (and the label dose was created) it is likely that gram (-) organisms were in fact, more susceptible to ampicillin. Target concentrations represent information not widely discussed when ampicillin was approved, but it is likely that gram negative organisms have become more resistant.

It would appear that ampicillin remains a viable drug for gram (+) infections. This does not say that resistance to ampicillin in certain gram positive populations is not a problem.

Exercise

Download ampicillin.xlsx, the worksheet for this module. Depending on your settings, you may have to "enable editing" in order to make the changes suggested by the exercise.

Pharmacokinetic variables on the worksheet are preset for ruminant calves and specific dose forms and routes.

You need not change the pharmacokinetic settings for this exercise.

Target concentrations

Manipulate the dosage

Inspect

Steady-State Concentrations (for repeated doses during therapy).

Graphs

Assess