Pharmacokinetics of different routes of administration of misoprostol.
BACKGROUND
The pharmacokinetic parameters of four different routes of administration of a single dose of 400 microg of misoprostol were studied.


METHODS
A total of 40 women undergoing termination of pregnancy by suction evacuation was randomized by computer model to receive 400 microg of misoprostol by one of four routes: (i) sublingual (ii) oral (iii) vaginal and (iv) vaginal with addition of water. Venous blood samples were taken at 0, 1, 2, 5, 10, 20, 30, 45, 60, 120, 240 and 360 min after the administration of misoprostol. Misoprostol acid (MPA) was determined in serum samples using gas chromatography/tandem mass spectrometry.


RESULTS
Sublingual misoprostol achieved the highest serum peak concentration (Cmax) (574.8 +/- 250.7 pg/ml) of MPA and this was significantly higher than those in the other groups [Oral: 287.6 +/- 144.3 pg/ml (P < 0.01), vaginal: 125.2 +/- 53.8 pg/ml (P < 0.001) and vaginal with water: 162.8 +/- 57.1 pg/ml (P < 0.001)]. The time to peak concentration (Tmax) was similar in both the sublingual (26.0 +/- 11.5 min) and oral groups (27.5 +/- 14.8 min) and was significantly shorter than those in both vaginal groups. The area under the MPA concentration versus time curve up to 360 min in the sublingual group (743.7 +/- 291.2 pg.h/ml) was significantly greater than those in oral (402.8 +/- 151.6 pg.h/ml, P < 0.05) and vaginal (433.7 +/- 182.6 pg.h/ml, P < 0.05) groups, but no significant difference was found between sublingual and vaginal administration if water (649.3 +/- 333.8 pg.h/ml) was added.


CONCLUSIONS
The new sublingual route of administration of misoprostol demonstrated a great potential to be developed into a method of medical abortion.
Tang
Oi Shan
OS
Department of Obstetrics and Gynaecology, The University of Hong Kong, Queen Mary Hospital, Hong Kong SAR, China. ostang@graduate.hku.hk
Schweer
Horst
H
Seyberth
H W
HW
Lee
Sharon W H
SW
Ho
Pak Chung
PC
D000020:Abortifacient Agents, Nonsteroidal / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D000282:Administration, Intravaginal; D000284:Administration, Oral; D000286:Administration, Sublingual; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D016595:Misoprostol / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D009994:Osmolar Concentration; D014867:Water
D000020:Abortifacient Agents, Nonsteroidal; D014867:Water; D016595:Misoprostol