A simple and sensitive spectrofluorimetric method has been developed and validated for the determination of the antidepressant clomipramine hydrochloride in its dosage forms. The method was based on the fluorescent ion-pair complex formation between clomipramine and alizarin red S at pH 1.99. The ion-pair complex showed maximum fluorescence intensity at 561 nm with excitation at 490 nm. Different variables affecting the reaction conditions such as the concentration of alizarin red S, pH, reaction time and the extracting solvents were carefully studied. Under the optimised conditions, the fluorescence intensity was found to be linearly related with clomipramine hydrochloride concentration in the range of 1.0–20 μg ml−1. The detection and quantitation limits were 0.32 and 0.97 μg ml−1, respectively. No interference was observed from the excipients commonly present in dosage forms. The proposed method was successfully applied to the determination of clomipramine in its pharmaceutical tablets with good accuracy and precision; the recovery values were 99.75–100.05%.
