Bioavailability, bioequivalence and biosimilars modeling

Bioavailability refers to the rate at which and extent to which the active ingredient is absorbed into the body and is made available at the intended site of drug action. 

Bioavailability studies are carried out by measuring the concentration of the drug in the plasma or blood after administration of the drug, with results documented over time. 

If two drugs are bioequivalent, there is no clinically significant difference in their bioavailability. A biosimilar is a biologic that is highly similar to another biologic already approved. 

Subtle changes in manufacturing processes, starting material and excipients may affect the efficacy and safety of biosimilars. Therefore, a biosimilar must be shown to be bioequivalent to the original drug in terms of bioavailability, safety, purity and potency.

Phoenix® WinNonlin® is used to help model and measure pharmacokinetic & pharmacodynamic effects on biosimilars.