The non-aqueous titrimetric assay of the selected anti-inflammatory agents using tetra-n-butylammonium hydroxide as titrant

A potentiometric titration method in non-aqueous media is proposed for the determination of some commonly used anti-inflammatory agents. The direct potentiometric titration of three anti-inflammatory agents, namely mefenamic acid, fenbufen and ibuprofen; and the indirect potentiometric titration of diclofenac sodium was carried out in acetonitrile solvent using tetra-n-butylammonium hydroxide as titrant, at 25 degrees C and under a nitrogen atmosphere. The method was found to be highly accurate and precise, having a relative standard deviation of < 1.0% for all anti-inflammatory agents studied. Also, it was shown that the method could be successfully applied to the assay of commercial pharmaceuticals containing the above-mentioned anti-inflammatory agents. The validity of the method was tested by the recovery studies of standard addition to pharmaceuticals and the results were found to be satisfactory. The proposed method is simple, rapid and sufficiently precise for quality control purposes. (C) 1999 Elsevier Science B.V. All rights reserved.