[Analysis of etofenamate. Particular determination in biological material (author's transl)]

The determination of 2-(2-hydroxyethoxy)-ethyl-N-(a,a,a-trifluoro-m-tolyl)-anthranilate (etofenamate, active principle of Rheumon gel) following its isolation from biological material is reported. Depending on the method of extraction etofenamate, free and alkali-labile conjugated flufenamic acid, total conjugates or the sum of CF3-containing compounds (sum of metabolites) are isolated. Separation is achieved by TLC, quantitative determination is made by degradation to flufenamic acid and fluorimetric measurement in CCl4/trichloracetic acid at 372/445 nm. Etofenamate can be identified by TLC, derivatisation, UV- and fluorescence spectroscopy and differentiated from its metabolites. It is demonstrated that etofenamate is the main component of fenamates in inflamed tissue.