An inexpensive, rapid and sensitive spectrophotometric method for determination of trimipramine in tablets

In this study trimiprarnine is determined on the basis of its reaction with concentrated nitric acid. Trimipramine reacts with nitric acid at room temperature to give a blue color, which rapidly converted to yellow color having maximum absorbance at 390 nm. This reaction is relatively selective with 1 mg/L as visual limit of quantitation and provides a basis for a new sensitive spectrophotometric method. The color is stable for at least 24 h and the linear dynamic range of the method is 4-80 mg/L. The repeatability of method is good and relative standard deviation is about 2% for six repeated experiments carried out on the solution having a concentration of 40 mg/L trimipramine. This method is used for quantitative assessment of the target analyte in pharmaceutical preparations. Interferences studies showed that most of the studied compounds have no interferential effect on the presented method.