Article

Thermosensitive N-isopropylacrylamide-N-propylacrylamide-vinyl pyrrolidone terpolymers: synthesis, characterization and preliminary application as embolic agents.

Research Institute of Polymeric Materials, Tianjin Universtiy, PR China.
Biomaterials (impact factor: 7.4). 01/2006; 26(34):7002-11. DOI:10.1016/j.biomaterials.2005.05.094 pp.7002-11
Source: PubMed

ABSTRACT In this article, thermosensitive N-isopropylacrylamide (NIPAAm)-N-propylacrylamide (NPAAm)-vinyl pyrrolidone (VP) terpolymers (PNINAVP) were prepared by varying feed ratios with free radical copolymerization method. The composition ratios and molecular weights of PNINAVP were examined by NMR and GPC. The thermo-responsive behaviors of copolymer solutions in the absence and with addition of Iohexol, a radiopaque agent, were investigated by differential scanning calorimetry (DSC) and rheometer. The sol-gel transition of the copolymer solutions occurred reversibly within 1 min in response to temperature. Incorporation of Iohexol increased the transition time and transition temperature of PNINAVP solutions; the rheological properties were also influenced. It was observed that at body temperature, PNINAVP and Iohexol could form an integrated bulky hydrogel presumably due to the hydrogen bonding between them, which was favorable for the clinical follow-up and reducing toxic side effects. In vitro embolic model experiment indicated that 5 wt% 16:16:1H PNINAVP solution containing Iohexol displayed a satisfactory embolization effect. This solution was injected into the rete mirabiles (RM) of six swines through a microcatheter. The angiographical results obtained immediately after the operation showed a complete occlusion of the RM, and no recanalization was observed at postoperative month 1. The histological examination demonstrated no acute inflammatory reaction inside the RM and surrounding tissue. This work could provide a beneficial guidance for designing a new temperature-sensitive polymer-based embolic agent.

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    Article: Formulation and characterization of radio-opaque conjugated in situ gelling materials.
    Brandon Blakely, Bae Hoon Lee, Celeste Riley, Ryan McLemore, Chandrashekhar P Pathak, Brent L Vernon
    [show abstract] [hide abstract]
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    Journal of Biomedical Materials Research Part B Applied Biomaterials 04/2010; 93(1):9-17. · 2.15 Impact Factor
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Keywords

acute inflammatory reaction
 
angiographical results
 
clinical follow-up
 
copolymer solutions
 
differential scanning calorimetry
 
free radical copolymerization method
 
histological examination
 
integrated bulky hydrogel
 
new temperature-sensitive polymer-based embolic agent
 
NPAAm)-vinyl pyrrolidone
 
PNINAVP solutions
 
postoperative month 1
 
radiopaque agent
 
rete mirabiles
 
satisfactory embolization effect
 
sol-gel transition
 
toxic side effects
 
transition time
 
varying feed ratios
 
vitro embolic model experiment