Cobalt (II)-EDTA complex as a new reductant for phosphomolybdic acid used for the assay of trazodone

Abstract

A new spectrophotometric method for the assay of trazodone (TZ) has been described. TZ forms a complex in stoichiometric proportions with phosphomolybdic acid. The released phosphomolybdic acid from the complex with acetone is reduced with a new reductant (cobalt nitrate-ethylenediamine tetra acetic acid) to molybdenum blue, which has maximum absorption at 840 nm. Beer's law limits, precision and accuracy of the methods are checked by the UV reference method. This method is found to be suitable for the assay of TZ in the presence of other ingredients that are usually present in tablets. Recoveries are almost quantitative.