Bioequivalence

Bioequivalence is a term in pharmacology that refers to the expected in vivo biological equivalence of two proprietary preparations of a drug. If two products are said to be bioequivalent, it means that they would be expected to be, for all intents and purposes, the same.

Definition

Bioequivalence is defined as the absence of a significant difference in the rate and extent to which the active ingredient or active moiety in pharmaceutical equivalents or pharmaceutical alternatives becomes available at the site of drug action when administered at the same molar dose under similar conditions in an appropriately designed study.

Testing

Bioequivalence testing is performed by pharmaceutical companies for both new drug products, and their generic equivalents, for which they wish to interchange. This testing is required for the approval of generic drugs by FDA.

Factors affecting bioequivalence

Several factors can affect bioequivalence, including the drug's pharmacokinetics, its pharmacodynamics, and the individual patient's response. Other factors, such as the formulation of the drug, its manufacturing process, its packaging, and the stability of the drug can also affect bioequivalence.

Bioequivalence studies

Bioequivalence studies are usually conducted in healthy volunteers under fasting conditions. However, in some cases, such as for drugs with a narrow therapeutic index, these studies are conducted in patients. The most common design for bioequivalence studies is the crossover design.

See also

• Pharmacokinetics
• Pharmacodynamics
• FDA
• Generic drug
• Therapeutic equivalence