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%.