Synthesis and Self-Assembly of Poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide)-g-poly(acrylic acid) Gels

Abstract

A one-step scalable synthetic procedure results in gels of poly(acrylic acid) (PAA) cross-linked by poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (Pluronic). The rate of polymerization of acrylic acid in the presence of Pluronic is of 3 / 2 order in acrylic acid and of 1 / 2 order in the initiator concentration and is independent of the Pluronic concentration. The formation of cross-linked networks in the synthesis can be attributed to the hydrogen abstraction by Pluronic radicals from the propagating Pluronic-PAA copolymer. The Pluronic-PAA gels exhibit temperature-and pH-dependent swelling in aqueous solutions. Aqueous gel suspensions change the rheological behavior in a certain range of temperatures, which depend on the type of Pluronic used. Intraparticle assembly of poly(propylene oxide) segments can be invoked to explain the temperature-dependent swelling, while interparticle attractive interaction of the dangling chains of Pluronic is responsible for viscosification of the gel suspensions.

PEO-PPO Block Copolymers for Passive Micellar Targeting and Overcoming Multidrug Resistance in Cancer Therapy

“…Research on CPT stabilization has been intensively carried out using polymeric micelles consisting of PEG-poly(aspartate) block copolymers, generically designed as PEG-P(Asp) [20,[96][97][98][99], or different pristine and poly (acrylic acid)-conjugated (Pluronic-PAA) poloxamers [78]. The Pluronic-PAA family was designed to combine the solubilization capability of the block copolymer and the pHsensitivity of the polyelectrolyte [100,101] with the purpose of creating an acidic microenvironment suitable for avoiding or delaying the lactone hydrolysis.…”

Drug release from pH‐responsive thermogelling pentablock copolymers

“…Typically the hydrogel will dissolve or degrade into components that can be excreted through the renal system, precluding invasive removal procedures of the polymeric material. Numerous thermoresponsive hydrogels have been investigated for controlled drug delivery applications 16–22. In particular, the thermoreversible gel forming Pluronic® F127 triblock copolymer has been studied extensively due to its proven clinical effectiveness in injectable and topical drug delivery formulations 23–25.…”

“…Numerous thermoresponsive hydrogels have been investigated for controlled drug delivery applications. [16][17][18][19][20][21][22] In particular, the thermoreversible gel forming Pluronic 1 F127 triblock copolymer has been studied extensively due to its proven clinical effectiveness in injectable and topical drug delivery formulations. [23][24][25] However, the Pluronic 1 copolymer gels are fast-dissolving, and are also not sensitive to pH, and therefore cannot be used in applications such as glucose-sensitive release of insulin from pH-sensitive gels by incorporation of glucose oxidase.…”

Rheology and phase behavior of thermo‐reversible pentablock terpolymer hydrogel

“…The hydrogel displayed the gelation temperature between 4 and 37 °C (body temperature) and showed potential application as an injectable biomaterial. Bromberg and coworkers investigated a series of Pluronic‐poly(acrylic acid) (PAA) multiblock copolymer hydrogels, and observed the micelle‐like aggregates with substantially dehydrated PPO core and hydrated PEO‐PAA corona. Mallapragada and coworkers prepared the dual pH‐ and thermo‐responsive pentablock copolymer hydrogels based on F127 and various amine containing methacrylate monomers (DM(E)AEMA), and characterized their self‐assembled structures of the micellar solution and gel phases.…”