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absorption rate constant using deconvolution


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#1 Yao Peng

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Posted 18 June 2012 - 03:53 PM

Hi,

I have run the deconvolution based on i.v and oral data. Can anyone let me know how to get the absorption rate constant (Ka) based on the output data? There are only 2 parameters indicated in the output data: Smoothing_parameter_delta and lag time. Thanks in advance,

 

Regards,

Penny



#2 Simon Davis

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Posted 19 June 2012 - 08:07 PM

Penny - is there a reason why you don't estimate Ka using a compartmental model on your oral data?

 

WinNonlin`s numerical deconvolution is showing the varying rate of input over time in the output worksheet, but typically it is not a single #constant# even with the smoothing

 

  Simon.



#3 Yao Peng

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Posted 22 June 2012 - 02:57 PM

Simon,

Thanks for your reply. The %CV is large for Ka based on a compartmental model, so I have been thinking to find an alternative way. Yes, the input rate changs over time; but the log input rate vs. time during the time frame with 75% of the compound absorpted is close to linear. So I am wondering if I should estimate Ka based on the slop of only this portion of the curve.

Best,

Penny



#4 Simon Davis

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Posted 28 June 2012 - 12:24 PM

Hi Penny,

   Sorry for the delay but I've been out on the road.

 

  If your logged graph is giving you a straight line then I think you can treat Absorption as First Order, so yes fitting Ka will give you an approximation of that slope.

 

I think %CV is often large for Ka since you probably don't have very many samples in that short time period.

 

   Simon.



#5 raghava choudary

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Posted 28 August 2013 - 12:32 PM

The winnonlin compartment modeling on Oral data doesnt give Ka in the out put. Am i missing anything



#6 Linda Hughes

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Posted 28 August 2013 - 12:46 PM

It is called K01. The model equations and a drawing showing the parameters and compartments is given in the UI, if that helps make it clearer.

 

Linda






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