Introduction To Pharmacokinetics



Pharmacokinetics is the branch of pharmacology which looks at what the body does to a drug. It looks at the movement of a drug into the body, through the body and finally out of the body: it covers the Absorption, Distribution, Metabolism, Excretion (ADME) and the bioavailability of the drug.

The time course of a drug in a body - its pharmacokinetics - depend on the chemical properties of the drug and on patient-related factors. These pharmacokinetic properties can be described using several parameters including the following:

  • Half-life
  • Bioavailability
  • Elimination rate constant
  • Absorption rate constant
  • Volume of distribution
  • Area Under The Curve
  • Total Body Clearance

The value of these parameters can be found from graphs plotting the plasma concentration of the drug against time and by using a few equations.