Nanoscale Pluronic® micellar templates with varying %EO content for controlled drug release and cytotoxicity

Abstract

This study investigates the self-assembly in ethylene oxide (EO)-propylene oxide (PO)-based block copolymers (BCPs) with various molecular features like molecular weight, EO/PO ratio, HLB (Hydrophobic lipophilic balance) in aqueous solution environment. Our BCP solution systems exhibit significant changes in solution behaviour that showed micellization, micelle growth/ transition, and progressively phase separation (2ϕ), all of which are well explained by clear solution, blue point (BP) and cloud Point (CP) respectively. The solubilization of the highly hydrophobic anticancer drug-Quercetin (QCT) in such BCPs is examined using UV–Visible spectroscopy. The spectral findings inferred the dissolution capability of QCT in the examined copolymeric micellar systems in terms of drug loading efficiency (DL%), encapsulation efficiency (EE%), partition coefficient (P), and standard free energy of solubilization (ΔGo). Amongst the varied tested BCPs, it was observed that Pluronics® P123 and F127 exhibited an enhanced QCT solubilization capability than others and is explained in terms of hydrophobicity and hydrophilicity. The micellar size distribution profile expressed as hydrodynamic diameter (Dh) was determined for QCT-loaded and QCT-unloaded BCP micelles employing dynamic light scattering (DLS). The drug release profile was fitted employing various kinetic models, allowing this study to serve as an excellent foundation for QCT delivery. Reversed-phase High-performance liquid chromatography (HPLC) system determined the retention period in the QCT-loaded micelle while the structural alterations involved in Pluronics®-QCT system is inferred using small-angle neutron scattering (SANS). Fourier transform infrared spectroscopy (FT-IR) depicted the compatibility between Pluronics® and QCT which was validated further from the evaluated optimum descriptors using Gaussian 09 computational simulation framework. It was discovered that the QCT-loaded micelles exhibited a greater anticancer effect than free drug when tested in vivo on cancer cells. The anticancer activity of QCT-loaded F127 micelles was determined to be the strongest. Thus, the current study on QCT solubilization in Pluronics® will benefit considerably from its investigated outcomes.