Four-way parallel factor analysis of voltammetric four-way dataset for monitoring the etoposide-DNA interaction with its binding constant determination.

In this paper, a novel strategy in the application of the parallel factor analysis (PARAFAC) to a four-way voltammetric dataset was improved to evidence the interaction of etoposide (ETO) and calf thymus deoxyribonucleic acid (DNA) to determine the ETO-DNA binding constant. PARAFAC is one of the most commonly used techniques applicable to the decomposition of higher-order data arrays to focus on features of interest and provides a different resolution of the chemical problem of interest. Under optimized conditions, peak current data of a seven-sample set containing DNA in the range of 2.0-90.0 µM in the presence of ETO at a constant concentration (10 µM) at five different pHs were recorded as a function of potential and frequency and then arranged as a four-dimensional array. The characteristic curves of ETO and ETO-DNA complex were monitored from the potential, frequency, pH, and DNA concentration profiles obtained by PARAFAC decomposition of the fourth-order array. The binding constant, which is one of the principal parameters for the estimation of drug-DNA interaction and mechanism, was computed from the DNA concentration profile. The consequence of drug-DNA binding constant (K = 1.26 × 106) indicated that there was a significant interaction between ETO and DNA with the intercalation mechanism.