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The following message was posted to: PharmPK
Dear All
Can any one help me in finding out the exact half-life of Topiramate.
There is lot of difference in the reported half life.
Thanks well in advance.
Regards
Sudhakar
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The following message was posted to: PharmPK
Dear Sudhakar
Topiramate half life is 39+/-11 hrs. It is advisable to go for serum
topiramate analysis, as topiramate gets distributed in RBC cells. This
will minimize variability factor to some extent as compared to plasma
analysis.
Please refer to FOI available on www.fda.gov, for further details.
Hope, this will serve your purpose.
Thanks and regards
Mitesh Gandhi
Ranbaxy Laboratories Ltd
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The following message was posted to: PharmPK
Hi Sudhakar,
Is there really such a thing as an "exact" half-life? The half-life
would
really depend on the subject, the sampling times you choose to
capture the
elimination phase, the method you use to estimate half-life, fed vs.
fasted, disease state vs. healthy, and a variety of other factors that
might contribute to pharmacokinetic variability. I'm afraid if you're
looking for one "exact" number you are not acknowledging the reality
of the
drug's pharmacokinetics, or any drug for that matter. Why do you need
this
number? If it's for reporting, you might want to consider reporting the
range of literature values you have found. If it's for planning
sampling
times, you may want to consider using the best and worst-case
scenarios you
found in the literature as a guide. According to the FOI for this
drug, the
mean terminal elimination half-life is 21 hours:
http://www.fda.gov/cder/foi/nda/96/020505_000_clinical_rvw2.pdf
Hope this helps,
-Dave
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Copyright 1995-2010 David W. A. Bourne (david@boomer.org)