A validated HPTLC method for the quantitative determination of duloxetine hydrochloride and 1-naphthol in bulk and pharmaceutical formulation

Abstract

Duloxetine hydrochloride is an anti-depressant drug, while 1-naphthol is one of its hepatotoxic impurities. So, there was an urgent need to do simultaneous analysis for both the drug and its toxic impurity. Therefore, a validated high-performance thin-layer chromatography (HPTLC) method was established for the simultaneous separation and quantification of duloxetine hydrochloride and 1-naphthol in their binary mixture and pharmaceutical formulation. The utilized developing system consisted of a mixture of chloroform–ethyl acetate–benzene–33% ammonia solution (6:3:1:0.1, v/v). Densitometric scanning was used to detect the separated peaks at 233 nm using an ultraviolet detector. The validation of the estimated method was performed according to the International Conference on Harmonization guidelines. The results indicated that it can be used for the quality control analysis of the proposed mixture. The developed method showed advantages over the previously published TLC methods of having higher sensitivity and allowing the determination of duloxetine hydrochloride with and in the presence of its toxic impurity 1-naphthol.