Chemometric Exploration of Photostability of Ornidazole in Aqueous Solution with Soft and Hard Modelling Multivariate Curve Resolution Method

Abstract

The photodegradation study of ornidazole in an aqueous solution was performed by using the multivariate curve resolution-alternative least square technique. The sample solution was exposed to direct sunlight for 42 hours, and the spectroscopic data was obtained at predetermined intervals of wavelengths. MCR-ALS, which is a chemometric technique, was applied to the data set. Initially, soft modeling was used, followed by hard modeling. The results show that ornidazole undergoes photodegradation via a two-step process in an aqueous medium, with three species involved in the degradation process. The initial concentration of pure ornidazole decreases while the concentration of intermediate start increasing and the concentration of intermediate falls with the formation of a new product. Thus, we have got three pure spectra in the MCR-ALS process. The reaction kinetics was performed with the hard modeling technique using kinetic constrain and the rate constant of the reaction was found to be k1 = 0.0955 and k2 = 1.287, respectively.