New radiopaque polyHEMA-based hydrogel particles

Abstract

New iodine-containing polymeric hydrogel particles were prepared by suspension radical copolymerization of 2-hydroxyethyl methacrylate (HEMA), 3-(methacryloylamidoacetamido)-2,4,6-triiodobenzoic acid (MABA) and ethylene dimethacrylate (EDMA) in an aqueous medium using azobisisobutyronitrile as an initiator and magnesium hydroxide as a suspension stabilizer. To impart porosity to the product, cyclohexanol and 1-dodecanol were added as inert diluents to the polymerization mixture. Particles containing 27 wt % iodine produced radiopacity sufficient to observe a clearly visible X-ray image. The equilibrium swelling behavior of the particles in water was characterized. Swelling of the particles dramatically increased by converting the acid groups of MABA into their Na+ form. The more MABA the copolymer particle contain, the higher is their swelling in the Na+ form.

Review of the Development of Methods for Characterization of Microspheres for Use in Embolotherapy: Translating Bench to Cathlab

“…Embolic microspheres with intrinsic radiopacity have been described for many years with a multitude of experimental studies in the literature. Radiodensity has been introduced into the microspheres by incorporation of metals such as tantalum, barium, and iron, or addition of organic compounds containing iodine species . While this results in the material being able to absorb X‐rays, it can also adversely affect handling and administration of the microspheres due to rapid sedimentation resulting from the increased density .…”

Synthesis and characterization of uniform radiopaque polystyrene microspheres for X‐ray imaging by a single‐step swelling process

“…Recent literature of novel biomaterials shows that there is an increasing interest in developing radiopaque polymers as contrast agents for X‐ray imaging 1–21. The radiopaque polymeric agents may be used for various applications, e.g., imaging of blood pool1, 2 or certain body organs3 in order to detect or diagnose various disease states, monitoring embolization process,4–10 evaluation of implants used in surgery to determine their exact location,11–16 and dental composition 16–18…”

“…Radiopaque polymers have also been formed by polymerization of methyl methacrylate with metal salts of vinyl monomers such a barium or zinc acrylates 16. Another approach to preparing radiopaquepolymers is based on copolymerization of vinyl monomers containing covalently bound halogen atoms such as iodine with other vinyl monomers 4, 11–21. Radiopaque polymers were also synthesized by grafting iodine‐containing molecules onto preformed high‐molecular‐weight polymers 5–7, 15…”

Bench-To-Clinic Development of Imageable Drug-Eluting Embolization Beads: Finding the Balance

“…The incorporation of iodine-containing species into polymers has been a more widely studied approach, resulting in biomaterials useful in tissue bulking applications [32], orthopedic bone cements [33,34], vertebral disc repair [35,36] and as embolic microparticles [8,37]. The radiopacity can be introduced by: (1) the chemical attachment of a reactively functional iodinated species to preformed polymer particles [8,27,28]; (2) the inclusion of an iodine-bearing monomer during the particle polymerization stage [14,15,37]; (3) or by entrapment of an iodine-containing compound within the particle structure [13,24,31]. Whatever the approach, compounds consisting of iodinated benzyl groups (as found in most commercial x-ray contrast agents) are commonly employed as they offer synthetic flexibility and enable incorporation of high iodine contents per unit mass, which improves conspicuity.…”