In vitro comparative study of drug loading and delivery properties of bioresorbable microspheres and LC bead.

Drug loadable bioresorbable microspheres (BRMS) are specially designed for the treatment of hypervascular tumors through arterial embolization. These microspheres consist of carboxymethyl chitosan crosslinked with carboxymethyl cellulose, and are available at different size ranges varying from 50 to 900 µm in diameter. Similar to commercially available non-resorbable drug eluting microspheres, LC Bead® microspheres (LCB), BRMS were capable of loading more than 99 % of doxorubicin, an anticancer drug, from the solution within 2 h with highly similar kinetics (difference factor f 1 = 0.36; similarity factor f 2 = 97.99). Doxorubicin loaded BRMS exhibited the highest elution rate in the 30 % ethanol aqueous solution saturated with potassium chloride, and the elution time depended on the ratio between the amount of loaded BRMS and the volume of elution media. After injection through microcatheters, BRMS have a higher recovery rate of the microsphere weight than LCB (90.96 vs. 79.63 %, P = 0.026). Although loaded BRMS eluted more drug into the injection medium than loaded LCB (8.63 vs. 3.80 %, P = 0.0015), there was no significant difference in the drug delivery rate between BRMS and LCB (83.88 vs. 86.65 %, P = 0.504). This study compares the loading capability as well as the drug delivery rate of BRMS and a commercial product under a condition simulating a transcatheter arterial chemoembolization procedure and demonstrates the potential of drug loaded BRMS for the treatment of hypervascular tumors such as hepatocellular carcinoma.