Chemometrics exploration of the kinetics of the reaction between amlodipine and 1,2-naphthoquinone-4-sulfonate

Abstract

This work presents an exploratory study of the kinetic of the reaction between the drug, amlodipine, and 1,2-naphthoquinone-4-sulfonate (NQS) and gives an interpretation of the kinetic pathway. The kinetic reaction was investigated under pH10.50 and 25°C by UV–vis spectrophotometric data. Model elucidation was performed by principal component analysis (PCA), multivariate curve resolution-alternating least squares (MCR-ALS) and augmentation of data acquired in different conditions. A data analysis approach based on global hard-modelling was applied to further elucidate the mechanism of the kinetic process, resolve the kinetic and pure spectral profiles of the intermediates and products and evaluate the rate constants. The kinetic process was evaluated with different kinetic two-step consecutive models which their first step was a second-order step. The results of the global hard-modelling of different possible reaction pathways (models) were compared. In spite of the rank deficiency, model parameters in most cases can be obtained by hard-modelling of the single data matrices. However, for some of the kinetic models and experimental conditions, because of the rank deficiency of the concentration matrix, the pure component concentration and spectral profiles cannot be computed since the linear regression step cannot be performed. Here, we applied matrix augmentation to solve this problem.