Significance of the Bioavailability
and Bioequivalence

a- After a single dose:

For many drugs, the drug concentration has to exceed a certain value (the minimum effective concentration) in order for the drug to exert its pharmacological effects. The rate and extent of drug absorption will determine the onset, the duration and the intensity of the effect.

The onset of effect for product 1 is faster than product 2.

onset

The duration of effect for product 1 is longer than product 2.

duration

The intensity of effect for product 1 is higher than product 2.

Intensity

Product 3 and 4 will not produce any effect since the plasma concentrations did not exceed the MEC.

b- During multiple administration:

Administration of drug products with different bioavailability is exactly similar to administration of different doses of the drug. Products with lower bioavailability will achieve lower steady state concentration compared to products with higher bioavailability.

Bioavailability

Lower bioavailability
results in lower steady
state plasma concentration