Physicochemical investigations of interaction of antitumor etoposide with ionic and nonionic micelles: a spectroscopic, conductivity and voltammetric study.

AbstractThis work aims to comprehend the physicochemical interaction of etoposide (trade name “VP-16”) with biological membranes using biomembrane models. Surfactants, owing to their remarkable chemical similarity with biomembranes, can be used to simulate the interactions and behavior of VP-16 in biological systems. The present study explores the physicochemical interactions of chemopreventive VP-16 with ionic dodecyltrimethylammonium bromide (DTAB), sodium dodecyl sulfate (SDS), and nonionic TX-100 & Tween-80 surfactants at the molecular level using different techniques. UV-visible spectroscopy results at 298.15 K indicate that both hydrophilic and hydrophobic interactions significantly influence the solubility of the drug in micellar systems. According to the estimated partition coefficient (<italic>Kx</italic>) and binding constant (<italic>Kb</italic>) obtained from the differential mode of the UV-Vis, VP-16 exhibits better binding and partitioning with nonionic surfactants compared to ionic surfactants. Thermodynamic parameters (ΔHmo, ΔSmo, & ΔGmo) are computed from 298.15 K to 318.15 K with a temperature interval of 5 K using conductivity data. The positive values of ΔHmo and ΔSmo and the negative values of ΔGmo indicate the disruption of water structure during the micellization process in the presence of VP-16 and the spontaneous transport of drug molecules into micelles, respectively. Voltammetric data at 298.15 K show that DTAB and TX-100 favor the oxidation of VP-16. This kind of study may be used to modify currently available drugs, design new chemotherapeutics, and formulate effective drug delivery systems to boost the drugs bioavailability. [ABSTRACT FROM AUTHOR]