The chronopharmacokinetics of indomethacin suppositories in healthy volunteers

The pharmacokinetics of a single 100 mg indomethacin suppository were studied in 12 healthy volunteers on two occasions at least 7 days apart. Suppositories were administered in randomised order at 9.00 and 21.00 hours to see if there was evidence of a diurnal variation in kinetic parameters. The study failed to show a significant change in single dose kinetics with the time of suppository administration. This is in contrast to previous work [1] demonstrating a circadian rhythm in the kinetics of a single oral dose of indomethacin. This suggests that the chronopharmacokinetics of indomethacin is dependent on the function of the upper gastrointestinal tract.