Assessment of metabolites in bioequivalence studies: should bioequivalence criteria be applied on the sum of parent compound and metabolite?
OBJECTIVE
The objective of this study was to demonstrate the impact of the sum of parent compound and metabolite in bioequivalence assessment.


METHODS
Four drugs with active metabolite were selected to assess bioequivalence. Bioequivalence criteria of 80 - 125% were applied to the parent compound, the metabolite, and the sum of parent compound and metabolite.


RESULTS
The results indicated that the application of 80 - 125% bioequivalence criteria to the sum of parent compound and metabolite might be misleading.


CONCLUSIONS
The 90% confidence interval should be applied separately to the parent compound and each metabolite.
Mahmood
I
I
Office of Clinical Pharmacology and Biopharmaceutics, Division of Pharmaceutical Evaluation I., Food and Drug Administration, Rockville, MD 20852, USA.
D019540:Area Under Curve; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D018491:Dopamine Agonists / Q000493:pharmacokinetics; D004311:Double-Blind Method; D004873:Ergolines / Q000493:pharmacokinetics; D006801:Humans; D013810:Therapeutic Equivalency
D018491:Dopamine Agonists; D004873:Ergolines; C100269:ergocryptine