Sensitive extraction spectrophotometric methods for the determination of trazodone hydrochloride in pure and pharmaceutical formulations

Two simple, rapid and sensitive extraction spectrophotometric methods have been developed for the assay of trazodone hydrochloride (TRH) in pure and pharmaceutical formulations. These methods are based on the formation of chloroform soluble ion-association complexes of TRH with bromocresol green (BCG) and with methyl orange (MO) in a KCl–HCl buffer of pH 1.5 (for BCG) and in a NaOAc–HCl buffer of pH 3.29 (forMO) with absorptionmaximum at 415 nm and at 422 nm for BCG and MO, respectively. The reaction conditions were optimized to obtain the maximum colour intensity. The absorbance was found to increase linearly with increasing concentration of TRH, which was corroborated by the calculated correlation coefficient values (0.9992 and 0.9994). The systems obeyed the Beer law in the range of 0.9–17 and 1–20 mg/ml for BCG and MO, respectively. Various analytical parameters were evaluated and the results were validated by statistical data. No interference was observed from common excipients present in pharmaceutical formulations. The proposed methods are simple, accurate and suitable for quality control applications.