I have a steady state PK profile of a once daily dosed drug but lack the 24 h sample. I would like to duplicate the predose sample and use it as the 24 h concentration. Is there a setting within the NCA to do this or does that need to be doen by data manipulation upfront? if the latter I would appricate any comment on how this is best done. Thanks, Markus
Markus - if you leave the C24 sample blank then WNL will extrapolate a value using Lz if available to the time tau for AUCtau calculations (If C0 was blank then for steady-state, the minimum observed conc during the dose interval would be used) However if you want to deliberately duplicate the C0 value at time 24 also then I would; A) use the Data Wizard to; Step 1 filter to keep just the C0 records (optional Step 2 use Custom transformation to add a flag so others know you manually duplicated this value, if required for QC/audit) Step 3 Filter with Replace option to relabel time as 24 B) use a merge to merge this back into the original set C) use the resulting set for the NCA calculations. The same principle could be used to duplicate a sample e.g. when Day 12, 0h is also the Day 11, 24h sample. Simon.