Colorimetric methods for the determination of some tricyclic antidepressant drugs in their pure and dosage forms

This paper describes two sensitive colorimetric methods for determination of some tricyclic antidepressant drugs in their pure forms and pharmaceutical preparations. The first method is based on the charge-transfer complex formation between the hydrochlorides of amineptine, nortriptyline, clozapine and dothiepin as n-donors and 2,3-dichloro-5,6 dicyano-p-benzoquinone (DDQ) or p-chloranilic acid (p-CA) as pi-acceptors to give highly coloured complex species. The coloured products are measured spectrophotometrically at 460 nm and 525 nm for DDQ and pCA, respectively. The second method is based on the formation of an ion-association complex with bromophenol blue or thymol blue at pH 3.6, which is extracted into chloroform. The complexes have a maximum absorbance at 413 nm. The methods hold their accuracy and precision well when applied to the determination of the cited drugs dosage forms.