Binding Characteristics between Poly(ethylene glycol) and Hydrophilic Modified Ibuprofen in Aqueous Solution

Abstract

The solubility of ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID), is enhanced by synthesizing ibuprofen ester with a water-soluble polymer, poly(ethylene glycol) (PEG), and the product obtained functions as a nonionic surfactant (IBF-PEG800, IP800). The morphology and aggregation behavior of IP800 micelles and IP800/PEG complexes in aqueous solution are investigated by (1)H NMR technology, dynamic light scattering (DLS), isothermal titration calorimetry (ITC), and fluorescence resonance energy transfer (FRET). The microstructure of IP800 micelles is strongly related to the concentration of IP800. IP800 monomers can form looser micelles at relatively low concentrations and much tighter micelles at high concentrations. And the binding model of PEG with looser IP800 micelles dramatically depends on the molecular weight and concentration of PEG: PEG with lower molecular weight (MW < or = 2000 Da) inserts to the interface of the hydrophilic corona and hydrophobic core of IP800 micelles; PEG with higher molecular weight (MW > 2000 Da) binds to the surface of IP800 micelles, and one long PEG chain (6000 < MW < or = 20000 Da) wraps several IP800 micelles. Besides, the ratio of short chain PEG400 to IP800 micelles of the IP800/PEG complex is about 15:1 at a fixed concentration of IP800 (0.05 mM), and for the long chain PEG20000 it is 1:3-1:4.

Effect of Chain Length of PEO on the Gelation and Micellization of the Pluronic F127 Copolymer Aqueous System

“…A similar increase and then decrease in micelle size with increasing temperature has recently been reported for Pluronic L44 by Naskar et al They attributed the decrease to the transition of larger to smaller aggregates. Wei et al reported a similar size variation just above the CMC of a synthesized surfactant (ibuprofen–poly(ethylene glycol)). For our samples, this behavior is also observed for cases involving the addition of PEO.…”

Synthesis and Characterization of Poly(Ethylene Glycol) Based Thermo-Responsive Hydrogels for Cell Sheet Engineering

“…With increasing weight ratios of PEGDA to NIPAm, the LCSTs of the hydrogels increased at the corresponding molecular weight of PEGDA. Except for the 1:0.25PEG(508) and 1:0.5PEG(508) hydrogels that were synthesized from liquid PEGDA (Mn = 508), the LCSTs at Mn = 3400, 6000, 10,000 and 20,000 with the same co-monomer ratio decreased with an increase in the molecular weight as a consequence of decreased number of hydrophilic oxyethylene groups [39]. Furthermore, at the same weight ratio of PEGDA, increasing the molecular weight of PEGDA decreased a molar percentage of PEGDA, and, as a result, decreased the crosslinking density of the hydrogels.…”

NMR of liquid crystals and micellar solutions

“…The morphology and aggregation behavior of IP800 micelles and IP800/PEG complexes in aqueous solution have been investigated by 1 H NMR, DLS, ITC, and fluorescence resonance energy transfer (FRET) experiments. 138 Micelles formed by block copolymers of Methoxy PEG (MPEG)-b-poly(e-caprolactone) bearing ketone groups (P(CL-co-OPD)) have been proposed as carriers for doxorubicin, a representative anticancer drug. Their 1 H NMR spectra indicate that the polymers form micelles exposing hydrophilic segments to the aqueous environments.…”