Polymeric materials for embolic and chemoembolic applications

Abstract

Percutaneous transcatheter embolization procedures involve the selective occlusion of blood vessels. Occlusive agents, referred to as embolics, vary in material characteristics including chemical composition, mechanical properties, and the ability to concurrently deliver drugs. Commercially available polymeric embolics range from gelatin foam to synthetic polymers such as poly(vinyl alcohol). Current systems under investigation include tunable, bioresorbable microspheres composed of chitosan or poly(ethylene glycol) derivatives, in situ gelling liquid embolics with improved safety profiles, and radiopaque embolics that are trackable in vivo. This article reviews commercially available materials used for embolization as well as polymeric materials that are under investigation.

Impact of trivalent ions on the stability and cohesion of calcium polyphosphate coacervates for embolization applications

“…In this study, a 53 μm mesh size was used to quantify the formation of small coacervate “particulates” capable of distal penetration . This is consistent with the smallest commercially available degradable embolic particles, Gelfoam powder and starch microspheres, both of which are ∼50 μm . Trivalent ions at low concentrations did improve cohesiveness, as the PP coacervate with 5 mol % GaCPP D p 200 was found to be the most cohesive.…”

“…Cohesion is essential for liquid embolic agents to prevent the embolic agent from traveling to undesired locations and potentially causing life‐threatening complications. In this study, a 53 μm mesh size was used to quantify the formation of small coacervate “particulates” capable of distal penetration . This is consistent with the smallest commercially available degradable embolic particles, Gelfoam powder and starch microspheres, both of which are ∼50 μm .…”

“…Cohesiveness is essential for an embolic agent, as coacervate particles smaller than 50 μm pose a risk for non‐target embolization . The effect of composition on the cohesion of the coacervates was examined using the coacervates made without trivalent ions (i.e., Ca‐only PP, or CPP), 10 mol % Al, 10 mol % Ga, and the composition exhibiting the lowest degradation rate in the dissolution study.…”

“…These embolic agents all require the addition of a contrast agent, which would be eliminated by using an intrinsically radiopaque embolic agent. Liquid embolic agents are of increasing interest as they have the potential to penetrate deeply into the vasculature while reducing the risk of non‐target embolization, and can also be designed with the ability to provide predictable transient embolization …”

Engineered polymeric microspheres obtained by multi-step method as potential systems for transarterial embolization and intraoperative imaging of HCC: Preliminary evaluation

“…For their fabrication, natural polymers, such as gelatin, starch and chitosan and synthetic polymers such as polylactic-co-glycolic acid have been used [8,14,15].…”