SPECTROPHOTOMETRIC METHODS FOR THE ESTIMATION OF DULOXETINE HYDROCHLORIDE IN BULK AND IN PHARMACEUTICAL DOSAGE FORM

Three simple, accurate, sensitive and economical spectrophotometric methods have been developed and subsequently validated for determination of duloxetine hydrochloride in bulk and pharmaceutical formulation. Method A is an extractive spectrophotometric method based on formation of ion-pair complexes of duloxetine hydrochloride with Solochrome Black T, to form pink colored chromogen, which showed a maximum absorption at 512 nm, and obeys Beer's law in the concentration range of 2-10 μg/mL. Method B is based on the formation of charge transfer complexation reactions of duloxetine hydrochloride with picric acid to form a yellow colored chromogen, which showed maximum absorption at 420 nm and obeys Beer's law in the concentration range of 5-25 μg/mL. Method C is a UV spectrophotometric method using isopropyl alcohol as solvent, in which absorption maxima was at 290 nm, Beer's law obeyed in the concentration range of 5-30 μg/mL. The validation of the above methods was done and the results demonstrated that, the procedures were accurate, precise and reproducible. So, the proposed methods can be applied for the routine analysis of duloxetine hydrochloride in bulk drug and in its tablet dosage form.