Hello,
You're correct in identifying that the “sbionca” function in MATLAB calculates “Cmax” and “Tmax” based on noncompartmental analysis (NCA), which by default considers only the first occurrence of the maximum concentration for “Cmax/Tmax”.
In your case, because it’s multiple dosing, the concentration profile has multiple peaks, and “sbionca” is taking the first of those as “Cmax”, even though there is a higher peak later.
One workaround that can be used is manually compute “Cmax” and “Tmax”:
[maxConc, idx] = max(concentrationData);
Tmax = timeData(idx);
fprintf('True Cmax: %.2f at Tmax: %.2f hours\n', maxConc, Tmax);
The best practice for repeated dosing is to use steady state “Cmax” or to compute “Cmax” of the final dose.
Here is the output for the sample data I used along with manual computation of “Cmax “and “Tmax”.
Hope this helps!
