A - Absorption

This video is the second in the Pharmacokinetics series. It introduces Absorption, the A in the four elements (ADME) of pharmacokinetics. It describes various routes of absorption (e.g. oral or IV), and the effect the route has on properties such as Cmax.

Next Lesson: Distribution 

Take Home Message: The Route of Administration Matters

Depending on the route of administration, the Cmax will vary. Giving the same dose orally, intravenously, and via inhalation results in a different Cmax and Tmaxfor each.

Inhalation Cmax>IV Cmax>Oral Cmax.
Oral Tmax>IV Tmax>Inhalation Tmax.

Note that the AUC is unchanged.

When we look at giving a patient a dose of an actual drug, the formulation may already be chosen for us (dependent on the chemical properties of the drug). Infusing an IV drug over a different length of time, however, will affect the Cmax and Tmax in the same way as the route of administration. We will look at this effect later.