Modification of points used to calculate slope

NCA
1

Hello,

In simulations I’m running, I’m getting a lot of slopes not negative, so I looked at the pk profile for one of the id’s.

image

Is there a solution that would be feasible across many simulations (i.e., something that doesn’t involve manual manipulation of individual NCA runs/id’s).

I don’t think I have the ability to attach a file as a new user, so here’s the pasted data in case it helps:

|time|dv|
|0.001|0.161915379|
|2|0.150646588|
|4|0.378161585|
|5|0.426729701|
|6|0.389811447|
|7|0.439150713|
|8|0.472714324|
|10|0.688450261|
|12|0.616121128|
|14|0.48712011|
|16|0.5518173|
|20|0.706210206|
|24|0.499248799|
|29|0.508681025|
|36|0.532048053|
|43|0.502978878|
|50|0.593361679|
|57|0.37548746|
|64|0.334175661|
|71|0.400154777|
|78|0.206014774|
|85|0.431828928|
|89|0.428725532|

2

Posting here b/c new user and can’t post 2 images in one post:

image

3

Is there a solution that would be feasible across many simulations (i.e., something that doesn’t involve manual manipulation of individual NCA runs)

Could you describe how the manual procedure works?

Would you be able to fit a proper model to estimate the coefficient instead of relying on NCA here? The NCA methodology for computing the elimination rate constant where you increment the sample size to maximize adjusted R² seems generally problematic to me. In particular if you have a model with a relatively large residual error and possibly slow elimination.