Extractive spectrophotometric determination of some anti-inflammatory agents with methylene violet.

A fairly sensitive spectrophotometric method for the determination of ibuprofen, ketoprofen, piroxicam, diclofenac sodium, mefenamic acid or enfenamic acid in bulk samples and pharmaceutical preparations is described, based on the formation of a chloroform-soluble, coloured ion-association complex between the drug and Methylene Violet at pH 7.6.