High-pressure liquid chromatographic determination of ibuprofen in plasma.

A sensitive, simple, and rapid method for the quantitation of ibuprofen in plasma, using 1-(p-fluorobenzoyl)-5-methoxy-2-methylindole acetic acid as the internal standard, was developed. The method is based on reversed-phase high-pressure liquid chromatography with a mobile phase containing acetonitrile--0.1 M acetic acid (55:45 v/v). The chromatographic elution time was 8.5 min, and ibuprofen quantities as low as 0.1 microgram/ml can be assayed. The suitability of the method is demonstrated.