Biopharmaceutical Profile of Diclofenac-Misoprostol Combination Tablet, Arthrotec®

Arthrotec, a combination tablet has been developed that contains 50 mg of diclofenac in an inner core and 200 micrograms of misoprostol in an outer mantle. Both diclofenac and misoprostol are extensively absorbed and their maximum plasma concentrations, but not total availability, are diminished when taken with food. Both drugs have elimination half-lives of less than 2 hours and do not accumulate in plasma after recommended doses. Pharmacokinetic and bioavailability studies of the combination product taken separately and together reveal a high between- and within-subject variability in plasma diclofenac levels, especially when the enteric-coated tablets were given after food; reliable values for peak plasma diclofenac concentration could not be ascertained. No pharmacokinetic interactions between diclofenac and misoprostol were apparent. The bioavailability of diclofenac and misoprostol from the combination tablet was similar to that seen when the two drugs are given separately.