Bioequivalence and Bioavailability Forum

Dear Hari,

I'm not sure whether I do understand you completely...

❝ recently we have conducted a study, in which we have to dose 10 capsules to randomly seleceted couple of volunteers in a span of five minutes, but the dosing completion time will vary from subject to subject depending upon each subject.

Do you mean that every subject had to swallow 10 capsules within 5 minutes?

❝ so our doubt is we have to document whether the start time of dosing or end time of dosing.for uniform maintainance we have documented start time of dosing, is this time is going to show any effcet during analysis and pharmacokinetic analysis.

Yes this is correct; dosing starts with intake of the first capsule.
Otherwise (start time = intake of last capsule) imagine the following—only illustrative—example: the drug has a absorption half life of five minutes, and you start sampling every minute immediately after intake of the first capsule. In such a case you would get plasma concentrations at negative time points (because the first sampling point is recorded at t = -5 min). This would lead to a negative part of the AUC within t = -5 min and t = 0
Most PK-software also interpolate from t=0/c=0 to the first measured concentration (i.e., the first trapezoid is actually a triangle); if you fiddle around with negative time points your AUC may be incorrect.

If I misunderstood your question, please correct me.