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The following message was posted to: PharmPK
Dear all,
Are you aware of any method to estimate the effective half-life for
accumulation by using single dose PK parameters?
I have tried using ln(2)*MRTiv as well as a "weighted" sum of half-lives
where the weights depend on the contribution of each phase to total
AUC. It
did not work. Can you help, please?
Let's keep it simple and assume an intravenous bolus dose, a
2-exponential
model, linear and time-invariant PK
Many thanks in advance,
Henri
Henri Merdjan
Consultant for the Life Science Industries
PK and PK/PD specialist
NewFreelance sarl
Paris, France
+33 (0)6 23 97 67 34
hmerdjan.-a-.wanadoo.fr
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The following message was posted to: PharmPK
Dear Henri,
An approximation could be:
After single dose the R=AUCinf/AUCtau (R=accumulation ratio, tau is
whatever
intended dosing interval). You could then estimate the "effective
half-life"
using the equation
R=1/(1-e-ke*tau), t1/2 "effective" being 0.693/ke
Hope this helps
Anne Paccaly, Pharm.D.
Clinical Pharmacokinetics,DMPK,
Aventis, Bridgewater NJ
908-231 -2835 (Phone), 908-231-5933 (Fax)
E-mail:anne.paccaly.-a-.aventis.com
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