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NORMALIZE PK PARAMATERS FOR BODY WEIGHT NCA


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#1 Angus McLean

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Posted 26 April 2013 - 09:06 PM

Using Phoenix Nonlin (NCA module) the opportunity is presented for normalizing the PK paramaters such as AUC for dose administered, so that a total exposure value is given per unit mass drug administered ( e.g. mg). Now supposing one wanted to further normalize this vaue for body weight of the subject? There would of course be a column including the body weight of each of the individual subjects in the study together wiht the usual columns like time plasma concentrations e.tc.. Is this easy to do in Phoenix? It will involve dividing one column ( total exposure value is given per unit mass drug administered) by another column (body weight), but how to do that in Phoenix? Or is it better done by exporting to Excel and doing that normalization there.

 

 

Angus



#2 Ana Henry

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Posted 26 April 2013 - 09:25 PM

HI,

I would definitely do it in PHX because it is simple and it can be easily rerun if you change anything in your model. My recommendation is to carry weight in your NCA model so it is with your final parameters. if not in the original dataset then just use data>merge worksheets. Then do a Data Wizard (for PHX 1.3) or a Column Transformation (pre PHX 1.3), in both cases the transformation can be a simple arthimetric function x/y. Pick your x and y.

 

I have attached a PHX 1.3 project for you to view. Let me know if you need an earlier version.

 

Ana [file name=WeightNorm.phxproj size=375431]http://pharsight.com/extranet/media/kunena/attachments/legacy/files/WeightNorm.phxproj[/file]

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#3 Angus McLean

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Posted 27 April 2013 - 12:07 AM

Yes; Thank you Ana. I would like to include the subject weight in the original data set if it is available to me in a timely manner. I note the use of the "Data Wizard" and the mapping to achieve the extra ratio column in the final output.

 

If the subject weight is made available to me later.

 

So far I have not done data merge but I think it works by creating another Excel worksheet with just the subject weight plus all the common identifiers already inluded in the first worksheet. Then the 2 worksheets are merged so that the subject weihgt is now included in the data set.

 

Angus



#4 Angus McLean

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Posted 28 April 2013 - 08:16 PM

Ana: what I did do was I created another column for subject weight in my original worksheet {previously imported into Phoenix 6.3} and then copied and pasted the subject weights (in kg) from Excel into this vacant column.

 

Then I repeated your work involving the arithmetic transformation, which is basically dividing one column by another column. It went OK....thank you. I was a little confused by your use of "carrry". For your amusement I put that down to English not being your first language. Today I realize that the term "carry" is used in the program!

 

I have not reached "data merge" as yet or "data join" so I need to find out about that feature.

 

Presumably it pertains to having multiple worksheets as Data in Phoenix. For above example In the case of merging a subject weight worksheet you need have one with the common identifiers to the original worksheet (e.g subject number , treatment )

yes?

 

I am not clear about data structure you need to merge the one worksheet (with weight) with the original worksheet with the identifiers like subject number , treatment.

 

On the other hand "Data join" means that you join one worksheet to another?

 

 

Angus



#5 Ana Henry

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Posted 29 April 2013 - 05:29 PM

Hi Angus,

Both the 'Merge Worksheets' and 'Join Worksheets' options under the data category are similar. The Merge is what was in WNL5 and was left for historical purposes. The Data join accomplishes the same but has options for inner join or outter join. Inner join means that only data that matches (on the sorts) is displayed, outter join displays all the data even if it didn't match between the worksheets.

 

For any type of merges/joins you need to identify the sorts that will make your join have the correct information. For example, if the datasets has subject ids and weight then the subject ids is your sort. However, if the weight was measured per period then the subject and period would both be needed to merge the weight correctly for each profile.

 

I have attached a revised project with a merge and a join. Hope this is helpful.

 

Ana [file name=WeightNorm_v2.phxproj size=664685]http://pharsight.com/extranet/media/kunena/attachments/legacy/files/WeightNorm_v2.phxproj[/file]

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#6 Angus McLean

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Posted 29 April 2013 - 09:38 PM

Ana: Yes; this is brilliant. I find that I need to plug away here with the different aspects of this new program. Once I understand how the program works and the mentality of the program then I can be more creative. I understand perfectly your point about the in-common indentifiers needed for the worksheets to be joined or merged.

 

Angus






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