Question

I did an experiment on the pharmacokinetics of Caffeine. I used a calibration curve to calculate the amount of caffeine in each sample in (micrograms/ml) and calculated the amount of caffeine in the volume of a given urine sample lets say sample 1 has 300 ml, sample 2 350 ml, and so on. Which data should I use to find the total amount of unchanged in the urine in order to calculate the fraction excreted unchanged and renal clearance?

Answer 1

Answer :)

To calculate renal clearance we should need urine flow, the concentration of caffeine in the urine, and concentration of caffeine in the plasma too.

To find out the fraction excreted unchanged, we should need the value of renal clearance of caffeine and total clearance of caffeine (if any other means of elimination of caffeine is used). If there are no other means than the renal clearance, then the fraction excreted unchanged will be 1.