Hello!Back to the Top
I have a question concerning Tmax. Is there a diffrence in Tmax
obtained from a single-dose study compared to a study performed at
steady state? I'm just interested in the most simple case without any
time- or dose dependency.
Kind Regards
Henrik Wahlstrom
Dear Henrik,Back to the Top
"I have a question concerning Tmax. Is there a diffrence in Tmax
obtained from a single-dose study compared to a study performed at
steady state? I'm just interested in the most simple case without any
time- or dose dependency."
Yes, there is a difference, because with each consecutive (regular)
dose the observed maximum is shifted a bit to the left (assuming the
next dose is given after the maximum is reached), relative to the time
of the dose. Here is a numerical example:
Assume C(t)=B*exp(-beta*t)-A*exp(-alpha*t), and put A=B=1.0, alpha=1.0,
beta=0.2, tau=10 (dosing interval), n = number of dose, tn = tau*(n-1)
- time of the nth dose.
Then
n tmax-tn
1 2.012
2 1.853
3 1.833
4 1.831
5 1.830
6 1.830
.....
steady state 1.830
This case the difference is about 10% of tmax single dose.
Best Regards
Wojciech Jawien
Jagiellonian Univ.
Faculty of Pharmacy
ul. Medyczna 9
30-688 Krakow, Poland.
PharmPK Discussion List Archive Index page
Copyright 1995-2010 David W. A. Bourne (david@boomer.org)