Investigation of an anaesthetic drug (tetracaine hydrochloride) in the presence of ionic fluid and surfactant: Mixed micellization & spectroscopic studies

Abstract

The effect of ionic liquid and cationic surfactant on the physicochemical characteristic of an anaesthetic drug (tetracaine hydrochloride, TCH) has been studied in the current task. The ionic fluid (1-hexadecyl-3-methyl imidazolium chloride, SAIL) and cationic surfactant (cetylpyridinium chloride, CPC) used in this study are of the same hydrophobic chain length. Tensiometric and absorption spectroscopic methods have been castoff to study the interaction of TCH with SAIL/CPC. The critical micelle concentration (cmc) values of single and mixed amphiphiles were computed by the surface tension method. In addition to cmc, maximum surface excess concentrations (Γmax), minimum surface areas per surfactant molecule (Amin), surface tension at the cmc (γcmc), surface tension reduction efficiency (πcmc), and several thermodynamic parameters of mixed micellization were measured. The calculated average value for the interaction parameter (βRub) suggests TCH show higher synergistic interaction with SAIL compared to CPC. The better attractive interaction (synergism) between SAIL and TCH is also confirmed by UV–visible spectroscopy. The absorption spectra of the drug show increase in the absorption with increasing the concentration of surfactants without any shift confirming the formation of a new complex. The binding constant value is more for the TCH + SAIL mixture.