Spectrochromatographic determination of dorzolamide hydrochloride and timolol maleate in an ophthalmic solution using three-way analysis methods

In this study, the simultaneous spectrochromatographic determination of dorzolamide hydrochloride (DOR) and timolol maleate (TMM) in an ophthalmic formulation was performed by applying multiway resolution methods, parallel factor analysis (PARAFAC) and three way partial least squares (3W-PIS) models. In similar manner, unfolded partial least squares (U-PLS) approach was applied to the UPLC analysis of the related drugs. For the three-way resolutions, the ultra-performance liquid chromatography-photodiode array (UPLC-PDA) data array of the calibration samples and others (validation and commercial samples) containing the analyzed drugs (DOR and TMM) and thiamine hydrochloride as an internal standard (IS) was decomposed into triads or trilinear components. These three different calibration models were employed for the spectrochromatographic resolution of a commercial ophthalmic formulation of DOR and TMM and then successful quantitation results were obtained. Analysis results provided by applying three-way and two-way resolutions were statistically compared to those obtained by the newly developed standard UPLC approach. It was observed that the proposed methods gave comparable determination results for analysis of the DOR-TMM ophthalmic formulation.