The pharmacokinetics of the prostaglandin E1 analogue misoprostol in plasma and colostrum after postpartum oral administration.
OBJECTIVE
To study pharmacokinetics of prostaglandin E1 analogue, misoprostol in plasma and colostrum after postpartum oral administration.


METHODS
Twenty women received 600 microg doses of misoprostol orally after delivery. Plasma levels of the principal metabolite, misoprostol acid, were measured at 2, 10, 20, 30, 40, 50, 60, 90, 120, 180, 240 and 300 min (48 samples). Colostrum was expressed from the breasts to measure misoprostol acid at 60, 120, 180, 240, and 300 min (24 samples). Assay was done using isotope dilution gas chromatography (GC)/negative ion chemical ionisation mass spectrometry (MS).


RESULTS
The plasma concentration of misoprostol acid rose quickly. Two minutes after oral administration its mean level was 91.5 pg/ml, peaked at 20 min (344 pg/ml), then fell steeply by 120 min (27.8 pg/ml) and remained low for the duration of the study. Misoprostol acid in colostrum reached maximum concentration of 20.9 pg/m within 1h after oral administration. It then declined gradually to 17.8 pg/ml at 2h, 2.8 pg/ml at 4h and to <1 pg/ml at 5h. Areas under misoprostol concentration versus time curves up to 5h were 290.1 pgh/ml in the plasma and 51.4 pgh/ml in colostrum, respectively.


CONCLUSIONS
Misoprostol acid is secreted in colostrum within 1h of oral administration of 600 microg of misoprostol; the pharmacokinetics of misoprostol after oral administration during postpartum is similar to that of other pregnancy periods.
Abdel-Aleem
Hany
H
Department of Obstetrics and Gynecology, Assiut University Hospital, Assiut, Egypt. aleemh@yahoo.com
Villar
José
J
Gülmezoglu
A Metin
AM
Mostafa
Sayed A
SA
Youssef
Alaa A
AA
Shokry
Mahmoud
M
Watzer
Bernhard
B
D000293:Adolescent; D000328:Adult; D003126:Colostrum / Q000737:chemistry*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007700:Kinetics; D016595:Misoprostol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics*; D010120:Oxytocics / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D010298:Parity
D010120:Oxytocics; D016595:Misoprostol; C047042:misoprostol acid