Development of ion-association methods for the spectrophotometric assay of trazodone

Simple and sensitive spectrophotometric methods (M-1-M-3) for the assay of trazodone (TZ) are proposed. These methods are based on the formation of ion-association complex involving tertiary nitrogen of TZ and the acidic dye, supracene violet 3B (SV 3B) (M-1), tropaeolin 000 (TP 000) (M-2) or wool fast blue BL (WFB BL) (M-3). Beer's law and precision and accuracy of the methods are checked. The methods are suitable for the assay of trazodone in pharmaceutical formulations, and the recovery range is 99.17-99.16%.