5 Crucial Functions of Bioequivalence & Bioavailability in Drug Development

Bioavailability in pharmacology refers to the absorption rate of a drug by the systemic circulation. On the other hand, when two compounds show similar bioavailability, they can be referred to as bioequivalent.

What factors influence BA & BE studies?

The measure of bioavailability of any compound depends on three variables –

i.          The maximum concentration of the new compound in the systemic circulation

ii.         The time the compound takes to reach the maximum concentration

iii.        The area under the curve on the concentration vs. time graph

The form of administration, the tertiary structure of a molecule, and moieties other than the active ingredient can influence the bioequivalence study of a new drug molecule.

Five functions that make bioavailability and bioequivalence (BA & BE) studies during drug development critical?

Here are the 5 essential functions of bioequivalence and bioavailability during drug development –

i.          Progress of a new compound into further drug developmental stages

The low bioavailability of a drug can signify the necessity of chemical changes for improving its bioavailability. A drug may not be fit to progress into clinical trials due to its low availability and low efficacy in the test system. BA & BE studies in the early stages can help you understand if your drug of interest is ready to progress into the later stages of drug development.

ii.         Establishing the dosage regimen of a new drug

Bioavailability studies set the essential pharmacokinetic parameters of a drug, including the rate and extent of absorption, metabolism, rates of excretion, and the half-life of the compound after single and multiple doses. The established pharmacokinetic parameters are essential for standardized dosage regimens.

iii.        BA & BE studies help meet FDA regulations

Every new drug application (NDA) has six technical sections, including manufacturing, chemistry, and controls; human pharmacokinetics and BA; microbiology; non-clinical pharmacology and toxicology; clinical data; statistical data. Each abbreviated new drug application (ANDA) includes similar sections apart from a specific part of BE.

The FDA has developed several BA and BE guidelines that every NDA and ANDA submission should meet to provide recommendations to sponsors.

iv.        Comparative study of a drug molecule produced by different manufacturers

The Waxman-Hatch Act (Drug Price Competition and Patent Term Restoration Act) 1984 allows the use of bioequivalence studies for approving a generic copy of the available drug in the US.

The FDA has laid out transparent rules and guidelines for bioavailibility studies of a new generic compound against a brand-name drug. It boosts the generic industry and increases the availability of affordable medication.

v.         Exercise of better control of the quality of the drug products

The comparative bioavailability and absolute bioavailability studies of a new drug can elicit its absorption rate, metabolism, and half-time in a biological system. Different factors like the processing methods, storage, and stability of the drugs can influence the availability of a drug in a given system. 

The BA & BE studies of drugs can help in improving the quality of processing and storage of the drug.

BA and BE studies aim at determining the suitable dosage form, the influence of the excipients, drug-drug interactions, quality control, and the creation/approval of new generic drugs.