Self-assembling characteristics of 5-(α-acetamido-α-benzyl) methyl-5'-methyl imidazolidine-2,4-dione - a hydantoin drug

Abstract

Self-assembling characteristics of a hydantoin drug are determined using UV-visible spectroscopy, surface tension, conductivity and fluorescence methods. The critical micelle concentration (cmc) obtained by these methods are in good agreement with each other. The critical micelle concentration, aggregation number and standard free energy change of aggregation of the hydantoin in aqueous solution are 1.5 mM, 8 ± 1 and -15.9 kJ mol^-1, respectively, at 22°C. The aggregation number obtained by both steady-state and time-resolved fluorescence spectrophotometric methods are in good agreement with each other. Pyrene fluorescence quenching rate constants in hydantoin micelles with varying amount of quencher in the absence and presence of oxygen are found to be 6.2 ± 0.3 × 10⁹ and 1.7 ± 0.2 × 10¹⁰ M^-1 s^-1, respectively. Furthermore, here we have for the first time investigated that there is no need of adding any external fluoroprobe for the determination of the aggregation number of the micelles if the micelle forming substance contains a fluorescent excited state. The accessibility of the quencher to the total fluorescence in hydantoin micelles in the absence and presence of external probe viz. pyrene has also been estimated.