Concentration of ibuprofen in cervical mucus.

Concentrations of an acidic drug, ibuprofen, in cervical mucus and serum have been measured by HPLC after oral administration in six healthy volunteers. After an 800 mg single dose of ibuprofen, the concentration reached in cervical mucus was less than 4% of that in serum. It is postulated that because ibuprofen is an acidic drug which is not subject to 'ion-trapping' in the acidic environment of cervical mucus, it is not concentrated in this secretion.