10 replies to this topic

[brian davies]

I would like to perform some PK/PD simulations either as a direct or link model. What I want to do is to fix both PK and PD parameters and then simulate different doses and get resultant PK and PD profiles. So far, even with the great advice from Pharsight support, I have not been able to perform this function. Is it possible to do this without first having to fit the PK/PD?

 

regards

 

Brian

[Simon Davis]

Brian,

   which part(s) are holding you up?

 

  I saw that you have final parameter estimates from some previous modelling, you know the model you want to use and you have switched it "simulation" mode.

 

the two remaining things you need to supply WNL with are the sampling schedule

 

e.,g. an "x" column of time

 

0.5

1

2

4

8

12

24

36...

 

and the dosing schedule(s), e.g.

0 20

12 10

24 10

36 10

if you have more than one design/ profile then you will need to ensure they are identified as by mapping to SORT e.g. regimen

 

if you can please attach the project you're having problems with and then we can identify what step /option has been missed.

 

the attached example shows 4 different dosing regimens once, twice and three times daily dosing, to illustrate VIF in assessing sampling designs for a simple PK model, but the same principle would hold for PK/PD.

 

  Simon. [file name=Ex_17_sim_mult.phxproj size=313832]http://www.pharsight.com/extranet/media/kunena/attachments/legacy/files/Ex_17_sim_mult.phxproj[/file]

Attached Files

•  Ex_17_sim_mult.phxproj   306.48KB   401 downloads

[brian davies]

Simon

 

Thanks for the response. Not sure what is happening. When you say "attach the project" do you mean the assembled project in Phoenix or the data to assemble the project.

 

regards

 

Brian

[Simon Davis]

Brian, the"assembled project in Phoenix" please, i.e. "File | Save Project as" xxxx.PHXPROJ

 

as I did above. then we can see what settings are correct and what have been omitted or need some tweaking.

 

 Simon.

[brian davies]

project attached. I managed to run the simulation this morning but didn't get the response I wanted. It set initial values of the PD parameters to zero and then didn't change them.

 

regards

 

Brian [file name=simulations.phxproj size=506201]http://www.pharsight.com/extranet/media/kunena/attachments/legacy/files/simulations.phxproj[/file]

Attached Files

•  simulations.phxproj   494.34KB   412 downloads

[Simon Davis]

Brian the initial parameters which were set to zero were due to a mismatch in parameter names ( a Phoenix model can support re-mapping these)

in this case the quickest way to get the output I think you were looking for was just to type the info in to an "internal worksheet" as I've illustrated in the attached, I also named the worksheets to make it clear to track what was being mapped where.

Alternatively in this case we could have just re-named the parameters either in the original worksheet or using a "Column Properties" workflow object.

Simon. [file name=simulations-20110711.phxproj size=703067]http://www.pharsight.com/extranet/media/kunena/attachments/legacy/files/simulations-20110711.phxproj[/file]

Attached Thumbnails

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Attached Files

•  simulations-20110711.phxproj   686.59KB   0 downloads

[brian davies]

Simon

 

Thanks for this. It seems that it was as simple as unit names not matching. I will look at what you produced for me but the graph doesn't look exactly how I wanted it. I was looking to have 4 bolus IV injections with a 6 minute gap between them. The PD response should have returned to baseline between the injections - probably another case of me not inputting the data correctly.

 

kind regards

 

brian

[brian davies]

Simon

 

another quick question. How do I open the project that you sent. It is a Zip file which is easy to open but it gives me a folder containing loads of files and a file I cannot open because it is password protected.

 

Brian

[brian davies]

Simon

 

Thanks for this. It seems that it was as simple as unit names not matching. I will look at what you produced for me but the graph doesn't look exactly how I wanted it. I was looking to have 4 bolus IV injections with a 6 minute gap between them. The PD response should have returned to baseline between the injections - probably another case of me not inputting the data correctly.

 

another quick question. How do I open the project that you sent. It is a Zip file which is easy to open but it gives me a folder containing loads of files and a file I cannot open because it is password protected.

 

Brian

[Simon Davis]

I guess you're using IE, this is a known issue as a browser - if you rename the zip as a PHXPROJ then it will work fine. (Firefox doesn't seem to have this problem).

 

 Simon.

[brian davies]

Simon

 

The Zip file tells me that it is password protected

 

Brian