Bioequivalence and Bioavailability Forum

Dear John,

What if for some obscure reason the sponsor sent the CRO more test article that would be needed to run the study + the retention samples. Would they be able to ask the CRO to send them back the excess test article, and just keep the amount needed as retention samples ? I don't see a reason why this wouldn't be accepted, as long as the sponsor do not select themselves which bottle has to be sent back and which should be kept as retention sample.