Bio equivalence studies are required for filing of abbreviated new drug application (ANDA) which is basically for approval of subsequent new drug. These studies are indirect indicator of quality, efficacy and safety of product. It is comparison of two medicinal products containing same active substance. As per WHO Definition – Two pharmaceutical products are bioequivalent if they are pharmaceutically equivalent or pharmaceutical alternatives, and their bio-availability, in terms of peak (Cmax and Tmax) and total exposure (area under the curve (AUC)) after administration of the same molar dose under the same conditions, are similar to such a degree that their effects can be expected to be essentially the same.
These studies can be conducted where systemic absorption of product can be quantified by suitable bioanalytical methodology. In vivo documentation of equivalence is needed when there is a risk that possible differences in bioavailability may result in therapeutic in-equivalence like most of oral immediate release products having bioavailability problems, non-oral & non-parenteral products for systemic exposure, modified released, fixed dose combination, non-solution pharmaceuticals products etc. In certain case bioequivalence studies are not required for pharmaceutical equivalents products like parenteral, solution for oral use, powder for reconstitution, gaseous products, otic or ophthalmic aqueous products, aqueous topical products, aqueous inhalational products etc.
Bio equivalence studies should be conducted by following Good clinical practices (GCP), Good Laboratory Practices (GLP) and guidelines on ethics. There are country specific guidelines for conduct of bioequivalence studies and can be referred by following link below
A typical bioequivalence study has below mentioned activities depicted in flow chart
The FDA requires in vivo bioavailability studies to be conducted for a New Drug Application (NDA). Bioavailability studies are normally performed in healthy adult volunteers under some restrictive conditions such as fasting, non-smoking, and no intake of other medications. The drug is usually given in a crossover fashion with a washout period of at least five half-lives.
Process flow of Bio availability and Bio equivalence studies :
Dr. Manoj Karwa
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