Abstract
Xโray visibility is an integral design component of in situ gelling embolization systems for neurovascular treatment. The goals of this project included the synthesis and characterization of a unique intrinsically radioโopaque in situ gelling material for neurovascular embolization. The gels formed using MichaelโType Addition between pentaerythritol tetrakis 3โmercaptopropionate (QT) thiols and poly(propylene glycol) diacrylate (PPODA) with the addition of the new material Iodobenzoyl poly(ethylene glycol) acrylate (IPEGA), a radioโopaque agent, synthesized successfully as confirmed with ^1^H NMR. The PPODA and IPEGA were mixed using a syringe coupler with QT and buffer at pH 11 for 90 seconds. Gel mixes were weighed to provide equal molar thiols and acrylate groups, changing the present acrylateโbearing compounds wt % ratios from 100 PPODA: 0 IPEGA, 90:10, 80:20, 70:30, 60:40, 50:50, and 0:100. Formulations with 10% and above of IPEGA were Xโray visible. Rheology showed that increasing the amount of IPEGA decreased the storage. Kinetic FTโIR studies indicate that the amphiphilic nature of the PEG backbone increased the reaction rate of the phase segregated reactants. Second order reaction constant modeling showed a change in initial reaction rate from 0.0029 to 0.0187 (M sec)^โ1^ from the 10% to 50% IPEGA formulations respectively. ยฉ 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010