corrected by subtracting the baseline from the corresponding interval averaged from the two pre-dosing days, and as an example of this, how we would ask firms to do this, consider subjects from whom Rmax occurred from 6 to 8 hours after dosing. So if Rmax was observed during the interval corresponding to 1 o'clock to 3 o'clock p.m., then the correction would be done by subtracting the rate of potassium excretion from the baseline days that was observed from 1:00 to 3:00 p.m., and as I said earlier, it's subject- and period-specific.
Baseline corrections are done for potassium chloride drug products because we'd like to determine, as accurately as possible, the amount provided in the dosage form. The baseline reflects the amount of potassium provided in food. So we assume then, after dosing with potassium chloride tablets, the amount of potassium in urine excreted above and beyond the daily amount due to food is due solely from that which is provided from the drug product. Thus, the amount of potassium provided from the two formulations can best be determined by doing the baseline correction which would correct for the amount of potassium excreted from food intake.