From: Sebastien Bihorel <*Sebastien.Bihorel*>

Date: Thu, 22 Apr 2010 14:45:02 -0400

I am not sure how you ended up with:

Ke-2.1*Ln(Ke)=3.18

but you may want to look at the following link, which explain how the

Lambert function (not available in NONMEM as far as I know) could help

to solve for Ke:

http://www.mathhelpforum.com/math-help/pre-algebra-algebra/58685-solving-ln-x-kx.html.

The Lambert function should be available in Maltab, Mathematica, Maple,

or similar tools.

Sebastien

yhb5442387 wrote:

*> Dear Sebastien:
*

*> I have to say that my admiration to you is beyond the words,because you have directly pointed out the radical essence.Could the ke or the V/F,any one , be derived from the known Cmax,AUC,?As far as I have leaned ,the equations are as follows:
*

*> AUC=Dose*F/Ke*V,
*

*> Cmax=(F*Dose/V)*(exp(Ka*Tmax)-epx(Ke*Tmax)).
*

*> After the computation and transformation ,I was obstructed in the front of the following
*

*> : Ke-2.1*Ln(Ke)=3.18.
*

*> something like that, well I could not remember the constant number (2.1 e.g.) clearly. I am not able to solve that equation.
*

*> So,I decide to make some equations in the $PK,in which the CL V and Ka could all be expressed as the component of Tmax ,Cmax,and AUC at the same time.The suggestion you have made is usefull,but still a little problem :the Ke.
*

*> Thank you for your generous help.
*

*> 22 03:24:55，"Sebastien Bihorel" <Sebastien.Bihorel *

*> >
*

*> >It looks like you are trying to derive the unknown values of KA, CL/F
*

*> >and V/F from the known values of Tmax, Cmax and AUC (probably obtained
*

*> >from a non compartmental analysis).
*

*> >
*

*> >If that is really the case, you will need to know the values of the
*

*> >half-life of elimination or the slope of elimination Ke to solve for Ka
*

*> >and V/F (the following solutions assume a one-compartment model with
*

*> >linear absorption and elimination):
*

*> >
*

*> >CL/F = Dose/AUC
*

*> >
*

*> >V/F = (CL/F)/Ke
*

*> >
*

*> >KA = - (1/tmax)*ln[ exp(-ke*tmax) - (Cmax*V)/(F*dose) ]
*

*> >
*

*> >If you don't know Ke, you will have to solve for V/F and Ka numerically,
*

*> >prior to your simulation.
*

*> >
*

*> >Sebastien
*

*> >
*

*> >yhb5442387 wrote:
*

*> >>
*

*> >> Dear Nmuser:
*

*> >>
*

*> >> I would like to do a data simulation .The distributions of the drug
*

*> >> population pharmaockinetics were assumed to be normal.But the profile
*

*> >> that I have got is Tmax, Cmax,and AUC(the means and variances are
*

*> >> already known),instead of Ka,CL,and V. What the $PK modification
*

*> >> should I have to do in the model where the advan2 has been taken in
*

*> >> the $subroutine.
*

*> >>
*

*> >> F=1.
*

*> >>
*

*> >> Any suggestion would be appreciated.
*

*> >>
*

*> >> Yours,ye hong bo
*

*> >>
*

*> >>
*

*> >>
*

*> >>
*

*> >> --
*

*> >> 工作和生活,都要开心的过.
*

*> >> 你好,叶红波在此送上真挚的祝福.祝你开心,
*

*> >> 叶红波
*

*> >>
*

*> >>
*

*>
*

*>
*

*>
*

*> --
*

*> 工作和生活,都要开心的过.
*

*> 你好,叶红波在此送上真挚的祝福.祝你开心,
*

*> 叶红波
*

*>
*

*>*

Received on Thu Apr 22 2010 - 14:45:02 EDT

Date: Thu, 22 Apr 2010 14:45:02 -0400

I am not sure how you ended up with:

Ke-2.1*Ln(Ke)=3.18

but you may want to look at the following link, which explain how the

Lambert function (not available in NONMEM as far as I know) could help

to solve for Ke:

http://www.mathhelpforum.com/math-help/pre-algebra-algebra/58685-solving-ln-x-kx.html.

The Lambert function should be available in Maltab, Mathematica, Maple,

or similar tools.

Sebastien

yhb5442387 wrote:

Received on Thu Apr 22 2010 - 14:45:02 EDT