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Nonparametric superposition


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#1 Shu-Pei Wu

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Posted 03 May 2018 - 06:31 PM

Hi, Phoenix Support,

 

I recently came across this error message when I performed superposition on version 7.0.

"Specified cast is not valid."

 

How can I get it fixed?

Thank you,

Shu-Pei
 

 



#2 Simon Davis

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Posted 03 May 2018 - 08:51 PM

Hi Shu-Pei, this isn't really the support portal but a forum for users to discuss models etc. 

 

Next time I'd email support with your project illustrating the problem; and if this doesn't help that may still b ethe best approach.  However it happens I just saw this note whilst researching another case;

 

Symptom: Nonparametric superpositioning gives an error message of "specified cast is invalid"
 
Cause: With Phoenix 7.0 a new data layer has been introduced and this is behaving differently in specific situations. The error message “specified cast is invalid” implies that there must be some missing number or special character in one of the input columns and that the type of input column is text rather than numeric. When trying to cast the missing/special character as a number, the cast is failing, but the software traps it and reports it. This is new behavior of the new data layer.
 
SolutionChanging data type of input column in input sheet to Numeric. This will get rid of non-numeric values and will change it to null. Alternatively, you a data wizard object can be used to add a filter where Null values can be changed to 0. We have created a new issue in our QC database under QC 16653. This should have been addressed in Phoenix 8
 
  Simon.

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#3 Shu-Pei Wu

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Posted 03 May 2018 - 09:23 PM

Thank you for your response Simon, My apology, if it is not an appropriate post here, please remove it. Best regards, Shu-Pei

 

EDIT by Simon DAVIS

 

Full Quote removed as it just makes the thread unnecessarily long.

 

I'll leave the post as it may prove helpful to another user - I was merely pointing out that for a software error message like that you would typically get a quicker/more detailed response from Support@Certara.com.


Edited by Simon Davis, 04 May 2018 - 04:50 AM.


#4 sundar

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Posted 18 December 2020 - 12:18 PM

Dear all,

 

In NCA-Nonparametric superposition method, how to give an input for initial dose @ 0 hr (for eg., 10mg), then loading dose  (20mg) @ day 7 followed by constant maintenance dose (20mg) every month, your response is highly appreciated.

 

Thanks

S



#5 Simon Davis

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Posted 18 December 2020 - 01:45 PM

Dear Sundar, use the NPS option for variable dosing, be sure you complete the true administered dose.  See attached that assumes your unit of time is in days.  But honestly i would try to build and fit a model so you can perform simulations that I think will give you greater confidence in the predictions.

 

You should also ask yourself what it is you expect to obtain from the simulatlon. Is it just a 'pretty' line of peaks and troughs or do you wnat to estimate exposure with Cmax and AUC on particular days?  Perhaps confirm you sampling schedule will be adequte in a future trial etc.

 

  Simon.

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#6 sundar

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Posted 18 December 2020 - 02:13 PM

Thanks Simon for your quick review.

 

In regular dosing type, when loading dose is given as input - WNL consider this loading dose at what time point exactly. For eg., at 0 hrs., or later?  

 

Thanks

Sundar



#7 Simon Davis

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Posted 20 December 2020 - 09:39 AM

first dose should always be recorded as the start time of dosing so time=0.

 

everything else is relevant to that so, for example the end time of a 30 minute indusion would be 0.5 hours if you were woking in time units of hours, with the start time be 0.

  Simon.






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