Penny,
When I use a PKPD model with the PD compartment initialized at TIME=0 I
find that PRED for the PD compartment is initialized to the same value
whether EVID=1 or EVID=4 and has identical values at subsequent times.
So it seems that with an EVID=4 event the compartments are
re-initialized after they are reset.
Perhaps you should try EVID=4 with your more complex model and see what
happens.
Best wishes,
Nick
On 10-Mar-17 16:41, Zhu, Penny wrote:
Dear Nick and all
I thought about this option before but noted that EVID=4 will clear
all compartment.
My MODEL is a pk PD linked model. The starting condition for the PD
compartment is non-zero(baseline). Also the pk is a TMDD MODEL and
the starting condition for the receptor is also non-zero. I was
wondering how EVID=4 would clear/reset all compartments in this case.
Penny Zhu
On Mar 9, 2017, at 6:34 PM, Nick Holford <n.holf...@auckland.ac.nz
<mailto:n.holf...@auckland.ac.nz>> wrote:
Penny,
A simple solution using NONMEM is to put the different designs one
after the other and separate them with an EVID=4 data item on the
first dosing record for each design. You can a DESIGN data item value
for each design which then makes it simple to use the simulated data
in a subsequent NONMEM estimation run using ACCEPT or IGNORE on the
$DATA record.
That way you can do the simulation just once and be sure to have all
the random effects (ETA) identical for each subject.
Best wishes,
Nick
On 10-Mar-17 12:11, Faelens, Ruben (Belgium) wrote:
Hi Penny,
Nonmem indeed calculates each subject one after the other. The
random values will therefore change. Maybe you can set the random
seed every time you simulate t=0, based on the subject ID?
This may also depend on your data file; have you tried ordering on
time (so the first 50 rows are all t=0 for subject 1 to 50) ?
This largely depends on the simulation software and its design:
As an example: Simulo samples all subjects together at simulation
start, after which it runs the trial design; so the same subjects
are sampled independent of subsequent trial design.
I do not know about other tools (TS.2, simulx, mrgsolve), maybe the
authors of these tools can specify?
Kind regards,
Ruben Faelens
*From:*owner-nmus...@globomaxnm.com
[mailto:owner-nmus...@globomaxnm.com] *On Behalf Of *Zhu, Penny
*Sent:* donderdag 9 maart 2017 19:19
*To:* nmusers@globomaxnm.com
*Subject:* [NMusers] question about random seed for simulation
Dear All
I have finished a multiple dose simulation for 600 subjects and want
to perform a single dose simulation (different sampling time) on the
same subjects (same ETA as the first simulation). I used the same
seed for the simulation step, it turned out the first subject was
the same and the rest of the subjects are not and I am not sure
whether this was due to the fact that the two simulation has
different number TIME records. If so, I wonder what is the proper
way to set the simulation seed so that the ETAs for the second
simulation will be identical to the first one.
I know that I could output the individual parameter estimate from
the first simulation and import them into the second one. But I was
thinking if the random seed can be synchronized between the two
simulation, it could be an easier solution.
Your help is very much appreciated!
Thank you very much and best regards!
**
*Penny (Peijuan) Zhu, Ph.D.*
Associate Director Clinical Pharmacology
Cell: 862-926-9079
PD Bio-Pharma CDMA
Sandoz
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Princeton, NJ 08540
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--
Nick Holford, Professor Clinical Pharmacology
Dept Pharmacology & Clinical Pharmacology, Bldg 503 Room 302A
University of Auckland,85 Park Rd,Private Bag 92019,Auckland,New Zealand
office:+64(9)923-6730 mobile:NZ+64(21)46 23 53 FR+33(6)62 32 46 72
email: n.holf...@auckland.ac.nz
http://holford.fmhs.auckland.ac.nz/
http://orcid.org/0000-0002-4031-2514
Read the question, answer the question, attempt all questions
