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I am facing problem to make sampling time points in
fluoxetine biostudy. Its half-life of 7-15 days (nor
fluoxetine). Is it ok if i carry out be study in
single setup with large group, without doing
crossover, is it acceptable to international
regulatory authorities. Can you help me out?
Thanks and regards,
Dr ganesh Shetty.
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The following message was posted to: PharmPK
Dear Dr ganesh Shetty.
According to the FDA's Guidance for Industry
"Bioavailability and Bioequivalence Studies for Orally Administered Drug
Products - General Considerations"
C. Long Half-Life Drugs
"For a BE determination of an oral product with a long half-life drug, a
nonreplicate, single-dose, crossover study can be conducted, provided an
adequate washout period is used. If the crossover study is
BE study with a parallel design can be used. For either a crossover or
parallel study, we recommend that sample collection time be adequate to
ensure completion of gastrointestinal transit (approximately 2 to 3
the drug product and absorption of the drug substance. Cmax and a
truncated AUC can be used to characterize peak and total drug exposure,
respectively. For drugs that demonstrate low intrasubject variability
distribution and clearance, an AUC truncated at 72 hours (AUC0-72 hr)
used in place of AUC0-t or AUC0-inf. For drugs demonstrating high
intrasubject variability in distribution and clearance, AUC truncation
warrants caution. In such cases, we also recommend that sponsors and/or
applicants consult the appropriate review staff".
For Fluoxetine, you can go for a parallel study and truncate the
72 hours. But you have to pay special attention to the sample size since
this drug is a HVD.
Mutasim Al-Ghazawi, Ph.D
Faculty of Pharmacy
Univesity of Jordan
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