title: Formulation and characterization of radio-opaque conjugated in situ gelling materials.
abstract: X-ray 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 radio-opaque in situ gelling material for neurovascular embolization. The gels formed using Michael-Type Addition between pentaerythritol tetrakis 3-mercaptopropionate (QT) thiols and poly(propylene glycol) diacrylate (PPODA) with the addition of the new material Iodobenzoyl poly(ethylene glycol) acrylate (IPEGA), a radio-opaque 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 acrylate-bearing 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 X-ray visible. Rheology showed that increasing the amount of IPEGA decreased the storage. Kinetic FT-IR 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)(-1) from the 10% to 50% IPEGA formulations respectively.
authors.affiliation: Harrington Department of Bioengineering, Center for Interventional Biomaterials, Arizona State University, Tempe, Arizona 85287-9709, USA.
authors.forename: Brandon
authors.initials: B
authors.lastname: Blakely
authors.forename: Bae
authors.initials: B
authors.lastname: Hoon Lee
authors.forename: Celeste
authors.initials: C
authors.lastname: Riley
authors.forename: Ryan
authors.initials: R
authors.lastname: McLemore
authors.forename: Chandrashekhar P
authors.initials: CP
authors.lastname: Pathak
authors.forename: Brent L
authors.initials: BL
authors.lastname: Vernon
mesh_terms: D015097:3-Mercaptopropionic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D003287:Contrast Media / Q000138:chemical synthesis / Q000737:chemistry*; D004548:Elasticity; D004621:Embolization, Therapeutic; D005782:Gels; D006801:Humans; D066298:In Vitro Techniques; D007462:Iodobenzenes / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011409:Propylene Glycols / Q000737:chemistry; D012212:Rheology; D017550:Spectroscopy, Fourier Transform Infrared; D014783:Viscosity
chemical_list: D003287:Contrast Media; D005782:Gels; D007462:Iodobenzenes; D011108:Polymers; D011409:Propylene Glycols; C501435:pentaerythritol tetra(3-mercaptopropionate); C012504:polypropylene glycol; D011092:Polyethylene Glycols; D015097:3-Mercaptopropionic Acid