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Hello
If you have experienced a bioequivalence study of nizatidine, I want to
ask you
if you needed to demonstrate also bioequivalence for its active
metabolite, N-
desmethylnizatidine.
Nizatidine is converted to this metabolite only in proportion of 6-7%
(so,
metabolite levels very low) and I saw a bioequivalence study (next link)
without quantitation of metabolite.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?
cmd=Retrieve&db=PubMed&list_uids=12616667&dopt=Abstract
Thank you
Chem. Vlase Laurian
Dept. Pharm. Technol & Biopharmaceutics
Univ. Med. & Pharm. “Iuliu Hatieganu”
Cluj-Napoca
Romania
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Hi Vlase,
The general approach in bioequivalence studies is to measure the active
ingredient since it reflects better the process of absorption that is
important in such studies.
There are two instances where the assay of metabolite(s) may be
required:
1) If the ingredient in the dosage form is a pro-drug.
Most regulatory agencies are more comfortable if the bioequivalence
criteria are met on the chemical compound responsible for the
pharmacologic activity.
2) If the metabolite(s) have a significant contribution
to the overall pharmacologic effect; meaning the metabolite(s) levels
are close to the parent drug and their activity is similar to the
parent drug.
Have a nice day,
radu
Radu D. Pop
Director Biopharmaceutics
Pharma Medica Research Inc.
966 Pantera Drive
Mississauga, Ontario
Canada, L4W 2S1
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