BACKGROUND

The pharmacokinetics of vaginal misoprostol as a dry tablet or as a tablet moistened with normal saline or with acetic acid were studied.

METHODS

For this study, 42 women requesting termination of pregnancy at gestational age of <12 weeks were recruited and received 400 µg vaginal misoprostol tablets. They were randomized into three groups: (i) dry tablets, (ii) tablets moistened with 3 ml of normal saline and (iii) tablets moistened with 3 ml of 5% acetic acid. Venous blood samples were taken at 0, 15, 30, 45, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330 and 360 min after misoprostol administration. Misoprostol acid (MPA) was determined in serum samples using gas chromatography/tandem mass spectrometry.

RESULTS

The serum peak MPA concentration (C_max) was significantly higher and the time-to-peak concentration (T_max) was significantly shorter in the normal saline and acetic acid groups, when compared with the dry tablet group. Both areas under the curve at 240 and 360 min (AUC₂₄₀ and AUC₃₆₀) of the normal saline and acetic acid groups were also significantly greater than that of the dry tablet group. The coefficients of variation in C_max and T_max were highest in the normal saline group, while that of AUC₂₄₀ and AUC₃₆₀ were highest in the dry tablet group. The C_max was significantly higher in subjects in the dry tablet group with vaginal pH < 5 than in those with pH 5. There were no significant differences in other pharmacokinetic parameters between subjects with vaginal pH < 5 and those with vaginal pH 5 in all three groups.

CONCLUSIONS

Vaginal misoprostol tablets moistened with normal saline or 5% acetic acid achieved better absorption than the dry tablet. The use of vaginal misoprostol tablets moistened with normal saline or 5% acetic acid would potentially improve the clinical efficacy of misoprostol.

HKClinicalTrials.com registration: HKCTR-821.

Source:
http://humrep.oxfordjournals.org/rss/current.xml