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" <[email protected]
<mailto:[email protected]>>Hi,
>
>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
>>
>>
>>
>>
>> --
>> ??????????,????????????.
>> ????,????????????????????????.????????,
>> ??????
>>
>>
--
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