I am doing a PopPK study in neonates. The dose of the drug and the dosing rate (for the infusion) aren’t same among patients and not even same within the patient. Ie, for some babies the rate is 2.4 for others its 4ml/ hour. Sometimes, the rate isn’t the same within the baby itself.. eg, some samples are taken when the rate is 2,4, some at 4. Each baby doesn’t contribute equal number of samples.
How can I perform NCA on this data to get initial parameter estimates?
How to add the custom doses for PopPK?
How to get an optimum base model to start PopPK on this data? When should I add covariates?
Phoenix is very flexible accepting different dosing regimens. Most of the time, in the Setup/Dosing you can check “Use Internal Worksheet” and you can enter or map your dosing information. To get initial values from NCA you might need to only consider one dosing cycle depending how the data was collected. In the Phoenix Model you can enter your dosing as well as initial estimates by subject checking the box “Use Internal Worksheet” . You will not see that in the code but it will use the dosing and initial estimates from the internal worksheet. This can be seen in the results. You can take advantage of the ADDL and II columns for multi-dose designs.
If you could post your project and design, it might be easier for the group to help you with your questions.
NCA theory only accounts for a single dose event, either naive or at steady state, for calculation of any dose related parameters e.g. Volume and Clearance
I did take a quick look at your data but it didn’t seem to have any ‘real’ obs to fit, all values were 1 in IB_OB.