Optimized Loading of Idarubicin in CalliSpheres(®) Drug-Eluting Beads and Characterization of Release Profiles and Morphological Properties

This study aimed to investigate the idarubicin loading method, compatible stability with contrast agent, release profiles, and morphological properties of 50–150, 100–300, and 300–500 μm CalliSpheres(®). The amounts of idarubicin added, loading medium, loading condition, and drug concentration were investigated as factors influencing drug loading efficiency. The drug loading rate was negatively correlated with the amount drug added and diameter of CalliSpheres(®) and positively correlated with the drug concentration. Compared to loading in purified water and incubation at room temperature, 5% glucose, heating, and ultrasound could accelerate drug loading. The idarubicin loading efficiency was above 95% after 10 min for all three CalliSpheres(®) with the optimized method of adding 20 mg of idarubicin at a concentration of 2 mg/mL and incubating at room temperature. The drug leak rate was under 1% within 8 h after mixing with iopamidol. Drug release tests indicated the sustained-release performance of CalliSpheres(®), and the time to reach 75% of the release plateau level was 8, 26, and 51 min for 50–150, 100–300, and 300–500 μm CalliSpheres(®), respectively. After idarubicin loading, the diameters increased by 12%, 36%, and 38% for 50–150, 100–300, and 300–500 μm CalliSpheres(®), respectively, and the surface of CalliSpheres(®) was observed to become smoother than that before drug loading. All three CalliSpheres(®) presented satisfactory loading efficiency with the optimized method, as well as proper compatible stability and sustained release performance. Among them, 100–300 μm CalliSpheres(®) are recommended.