Bioequivalence and Bioavailability Forum

Hi ssk!

❝ How does BMI of a subject affect a BA/BE study.

In a cross-over design single dose study you will see hardly any influence at all (subjects act as their own control, differences mean out).
If you are performing a parallel design, the BMI probably should be narrower in oder to keep groups as homogenous as possible and minimize variability.

If you are planning a multiple dose study for a highly lipophilic drug (which rapidly distributes in body fat with a very slow elimination) based on single dose data you should be cautious, because the slow elimination will be more pronounced in subjects with a high BMI.

❝ What is the usual range of BMI to be taken for a study.

For healthy subjects in BE 18-29 kg/m² is quite common, but more restrictive ones like 18-27 kg/m² or even 20-25 kg/m² (making recruitment cumbersome - with only doubtful justification) are in practice.

For a discussion see this thread at David Bourne's PharmPK list.

Dear ssk,

the ideal BMI range to include a volunteer in study is 19-26kg/m2. If a person falls below or above the normal value it shows affect on drug distribution which indirectly shows affect on B.A.