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RE: incorporate lag time in ADVAN 6

From: Serge Guzy <GUZY>
Date: Tue, 8 Jun 2010 09:25:53 -0700

I suggest you to go to the html folder, open index.htm and look at
"absorption lag parameter". Usually the tlag is in the absorption
compartment (most often defined as compartment 1).Therefore ALAG1 is a
reserved variable that will create a delay (ALAG1) in the dose input
time (in compartment 1). For example ALAG1=THETA(1)*DEXP(ETA(1)) code
inserted in the PK block will result in the estimation of both the fixed
and random effect for that reserved variable ALAG1 (through THETA(1) and
ETA(1)).

Serge Guzy; Ph.D

President, CEO; POP_PHARM; INC;

www.poppharm.com

 

 

 

USAGE:

 $PK

  ALAG1= ....

 

 DISCUSSION:

 

 Absorption lag parameters are used with PREDPP. They are optional

 additional PK parameters. With NM-TRAN, they are symbolized in the

 $PK block by reserved variables ALAGn, where n is the compartment num-

 ber to which the parameter applies.

 

 There is one absorption lag time (parameter) associated with every

 possible dose compartment of the kinetic model (the output compartment

 is not a possible dose compartment) and the absorption lag time used

 for a given dose is that one associated with the compartment into

 which the dose is given (the dose compartment).

 

 The event time t on a dose record refers to the recorded time the dose

 was administered. In the case of a regular infusion, t is the time the

 infusion was initiated. An absorption lag time is an increment of

 time L such that the time that the dose is regarded (by PREDPP) as

 entering (or starting to enter) the system is t+L.

 

 Absorption lag times are optional in the sense that absorption lag

 times associated with compartments never used as dose compartments may

 be ignored. The values of absorption lag times that are not computed

 in PK are always understood to be 0.

 

 An absorption lag time for a dose is computed by the PK routine using,

 if needed, information in the dose record. When additional doses are

 specified on a dose event record, the absorption lag time applies to

 the dose and to all the additional doses. With a steady-state multi-

 ple dose the absorption lag time applies not only to this dose, but

 also to all the preceding implied doses. With a steady-state dose, the

 lag time should be less than the interdose interval.

 

 

From: owner-nmusers
On Behalf Of kehua wu
Sent: Monday, June 07, 2010 12:30 PM
To: nmusers
Subject: [NMusers] incorporate lag time in ADVAN 6

 

Hi,

I have concentration data from 4 clinical trials and one of those might
have a lag time. A nonlinear model was used to fit the data.

So I need to incorporate lag time into the differential equations. Does
anybody know how to do this?

Many thanks in advance.

Best,

Kehua


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Received on Tue Jun 08 2010 - 12:25:53 EDT

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