Dear all, I wonder how can we model continuous subcutaneuos infusion (c.s.c) for a protein drug given by a pump. The drug is input as zero order into the absorption compartment then absorbed as first order into the systemic circulation. From i.v. data we know that t1/2 is ~ 10 hrs, V is 100 mL/kg. From SC bolus we know that ka is about 0.5 hr-1 . I looked at the available models in WinNonlin library and could choose the c.i.v. infusion model no. 2 and first order input model no. 3 . (using multiple SC boluses at very small increments) Both could fit the data properly but I beleive they are not the correct models for such route of administration. I wonder whether you have a custom code with both zero and first order input (and 1 disposition compartment). Thanks for your help. KInd Regards, Youssef
Youssef, Have you upgraded to Phoenix WinNonlin yet? If so writing your own custom code with the graphical model builder is very easy, (the NLME examples guide is a good resource for this in the installation folder; C:\Program Files (x86)\Pharsight\Phoenix\docs 
I guess it would look something like this, you can refine it further using the textual editor if need be. Remember there is no upgrade fee for licensed users of WNL classic and the Phoenix models can be extended to population analysis if you choose to take the NLME module as well Simon.
