A multitechnique approach on adsorption, self-assembly and quercetin solubilization by Tetronics® micelles in aqueous solutions modulated by glycine

Abstract

Ethylene oxide-propylene oxide (EO-PO) block copolymer micelles are useful potential nanoreservoirs for the delivery of hydrophobic drugs. Considering that glycine is an excipient and can favorably affect the surface/micellar behavior and thus improve solubilization power/dispersion stability/wetting characteristics we have reported here studies on aqueous solution behavior of two commercially available branched block copolymers (Tetronics^®) with differing hydrophobicities namely Tetronics^® 1307 and 1304, hereafter referred as T1307 and T1304, in the presence of glycine. Steady state fluorescence studies using pyrene as a probe, equilibrium and dynamic surface tension measurements, wetting and dispersion stability studies of Teflon (polytetrafluoroethylene; PTFE) and solubilization studies of a hydrophobic antioxidant/anticancer drug quercetin (QN) have been examined. The cloud point (CP) and critical micelle temperature (CMT) decrease while micelle hydrodynamic size (D_h) increases with the addition of glycine as well as on loading of the drug in the micelles. Water penetration through packed PTFE powder and dynamic surface tension confirm the enhanced micellization process for aqueous Tetronic^® solutions in presence of glycine and accordingly restricted diffusion for the surfactant molecules towards air-water and PTFE-water interface. The contact angles for Tetronic^® solutions in presence of glycine indicate moderate decrease. The pressure-area curves of the copolymers in water and glycine solutions were also constructed. Surface and micellar properties of copolymers are markedly altered in the presence of glycine and can be tuned for use of these nanocarriers in delivery systems.

Keywords: CMT; Contact angle; Glycine; Quercetin solubilization; Tetronics; Wetting.