MIFE taken orally shows non-linear pharmacokinetics. It is rapidly absorbed and distributed, reaching peak concentrations after 0.75 hours. It is 94-99% plasma-bound and is metabolized by CYP enzymes, mainly CYP3A4. Elimination is relatively slow with a half-life ranging between 83 and 90 hours[10].

MISO‘s pharmacokinetic profile varies substantially depending on the route of administration[10]:

• Buccal: time to first uterine contraction is 67 minutes, sustained for about 90 minutes and begins to decline at 5 hours after administration. The uterine response appears similar to that of vaginal administration, with less inter-individual variability.
• Vaginal: time to first uterine contraction is 82 minutes for dry tablets and 98 minutes for moistened tablets, sustained activity is attained at 106 minutes and 128 minutes, respectively, and uterine activity begins to decline at five hours after administration.
• Sublingual: tablets are absorbed through the mucosa within 20 minutes and MISO reaches peak serum concentration at 30 minutes. First-pass metabolism is avoided.