A Comparative Study on Micellar and Solubilizing Behavior of Three EO-PO Based Star Block Copolymers Varying in Hydrophobicity and Their Application for the In Vitro Release of Anticancer Drugs

Abstract

Abstract:The temperature and pH dependent self-assembly of three star shaped ethylene oxide-propylene oxide (EO-PO) block copolymers (Tetronics ® 304, 904 and 908) with widely different hydrophobicity was examined in aqueous solutions. Physico-chemical methods viz. viscosity, cloud point, solubilization along with thermal, scattering and spectral techniques shows strongly temperature and salt dependent solution behavior. T304 possessing low molecular weight did not form micelles; moderately hydrophilic T904 remained as micelles at ambient temperature and showed micellar growth while very hydrophilic T908 formed micelles at elevated temperatures. The surface activity/micellization/solubilization power was favored in the presence of salt. The copolymers turn more hydrophilic in acidic pH due to protonation of central ethylene diamine moiety that hinders micelle formation. The solubilization of a model insoluble azo dye 1-(o-Tolylazo)-2-naphthol (Orange OT) and hydrophobic drugs (quercetin and curcumin) for copolymer solutions in aqueous and salt solutions are also reported. Among the three copolymers, T904 showed maximum solubility of dye and drugs, hence the in vitro release of drugs from T904 micelles was estimated and the effect on cytotoxicity of loading the drugs in T904 micelles was compared with the cytotoxicity of free drugs on the CHO-K1 cells. The results from the present work provide a better insight in selection of Tetronics ® for their application in different therapeutic applications.

Brain targeting efficiency of intranasal clozapine-loaded mixed micelles following radio labeling with Technetium-99m

“…Tetronics (poloxamines) possess X-shaped structure which consists of chains of PPO–PEO blocks linked to central ethylene diamine group, the tertiary amine central groups has a major task regarding the thermodynamic stability of Tetronics (Vyas et al, 2018 ).…”

Self-Association in EO–BO–EO Triblock Copolymers as a Nanocarrier Template for Sustainable Release of Anticancer Drugs

“…The solubilization efficiency of the drug into the BCP micelles depends on the compatibility between the drug and micellar core of polymers, while the drug release depends on the localization of the drug into the micelle. − Studies have reported that the hydrophobicity of BO blocks is six times greater than the PO blocks in commercially available Pluronics and Tetronics. , Hence, BO blocks show better compatibility with hydrophobic anticancer drugs. In our study, the released profile of curcumin and quercetin in 5%w/v 39–47–39 was examined for suitable application in a sustainable release.…”

“…A series of more hydrophobic BCP counterparts with a similar architecture but with the replaced PO segment by a more hydrophobic poly­(butylene oxide) (BO), − poly­(styrene oxide), or phenylglycidyl ether have been proposed. Among them, special attention has been paid to the BCP with 1,2-butylene oxide (BO) as the hydrophobic block which is demonstrated to be “biologically active”. − Such behavior is attributed to the superior hydrophobicity of the BO block compared to PO (about sixfold as estimated from the ratio of the logarithms of the molar cmc). This enables the micellization at much lower copolymer concentrations which make them act as excellent drug delivery nanocarriers.…”

Nanodrug Delivery Systems for the Treatment of Ovarian Cancer

“…Nanomicelles are classified into three key distinct nanosystems i.e., colloidal nanomicelles formulated from an aggregation of polar and nonpolar molecules in an aqueous solution (amphiphilic aggregates), polyionic nanomicelles formulated from oppositely charged polymers generating an agglomeration due to electrostatic interaction, and nanomicelles originating from metal complexation [63][64][65][66].…”