| Gelatin Sponge (Gelfoam®) | Gelatin derived from pigs, purified | Particle size typically ranges from 0.5-2 mm | Temporary occlusion, with recanalization occurring within a few days to weeks | Gelatin sponge, marketed as Gelfoam®, is a commonly used hemostatic agent. It facilitates repeated intra-arterial treatment, but its larger particle size can lead to clumping in larger arteries and may not penetrate small vessels effectively. Gelatin sponge is also available as a powder, allowing for more distal embolization but with a higher risk of non-targeted embolization. |
| Polyvinyl Alcohol (PVA) | PVA particles with variable size and shape | Particle sizes ranging from 100-1,200 µm | Offers permanent or semi-permanent vessel occlusion. Some PVA-based microspheres are designed for TACE specifically. | Several PVA-based microspheres are available, including PVA (Cook, Bloomington, USA), Contour SE® particles (Boston Scientific, Natick, USA), and Bead Block® (BTG, Surrey UK). DC/LC Bead® (BTG, Surrey UK) is a PVA microsphere with a hydrogel core. Studies have shown little difference in patient survival between TACE using gelatin sponge and TACE using PVA particles. |
| Embosphere® | Spherical polymeric microspheres made of trisacryl cross-linked with gelatin | Available in calibrated size ranges | Provides permanent vessel occlusion without aggregation. Known for its smooth, hydrophilic surface and deformability, allowing it to penetrate deeper and embolize smaller vessels compared to PVA particles. | Embosphere® is marketed by Merit Medical and offers a potential advantage in terms of uniform particle size and effective embolization, but its clinical effectiveness compared to other agents remains uncertain. |
| Embozene® | Long-acting embolizing agent with a hydrogel core of polymethylmethacrylate and an exterior shell of polyphosphazene (Polyzene®-F) | Available in tightly calibrated sizes (100, 250, 400, 500, 700, and 900 µm) | Offers tightly controlled particle size, with 95% of particles within 50 µm of the nominal size. Its anti-inflammatory and bacterial-resistant properties are an advantage. | Embozene® microspheres provide precise control over particle size, but it's yet to be demonstrated whether this tight control results in additional clinical benefits for embolization procedures. |
| Degradable Starch | Sterilized starch microspheres suspended in saline solution | Size available is 50 µm | Provides transient occlusion of small arteries. Degradation occurs within 60-80 minutes due to serum-amylases, restoring blood flow. Suitable for patients who may not tolerate long-acting embolic agents. | Degradable Starch Microspheres, such as Spherex® and EmboCept S®, offer a shorter-duration occlusion and can be used in combination with anticancer drugs for palliative measures. Their rapid degradation reduces the risk of long-term vessel occlusion. |
| Lipiodol® | Oily contrast medium with an iodine content of 38 percent by weight | Viscosity at 37 ℃ is approximately 25 mPa.s, density is 1.28 | Provides transient and plastic embolization of tumor microvessels. When selectively injected into the hepatic artery, Lipiodol® selectively remains in tumor nodules for an extended period. | Lipiodol® is utilized as a vehicle for carrying and localizing anticancer drugs within tumors. It has tumor-seeking properties and can be used for various therapies, including immune or gene therapies. While not designed for complete and permanent arterial occlusion, it remains in tumor nodules for an extended duration due to tumor hypervascularization and absence of Kupffer cells. |
| Drug-Eluting Beads (DEBs) | Biocompatible, nonresorbable PVA polymeric microspheres doped with sulfonyl groups | Available in various size ranges (100-300, 300-500, 500-700, and 700-900 µm) with drug loadings varying from 5 to 45 mg/mL hydrated beads | Allow for fixed dosing and controlled release of anticancer agents. Significant reductions in peak plasma concentrations compared to conventional chemoembolization have been observed. | Two commercially available DEBs are DC/LC-Beads® (Biocompatibles, UK) and HepaSphere® (BioSphere Medical, Inc., USA), both capable of loading doxorubicin for HCC treatment. They provide a means of controlled drug release, potentially enhancing treatment efficacy. |
| Irinotecan-Eluting Bead | DEBs loaded with irinotecan hydrochloride solution | Particle size ranges from 100-900 µm | Sustained drug release dependent on elution medium, drug loading, and bead size. Undergoing clinical trials for the treatment of liver CRC metastases. | Irinotecan-eluting beads combine embolization beads (DEBIRI®) with irinotecan for treating CRC liver metastases. The sustained drug release profile is being evaluated in ongoing randomized clinical trials. |
