Superabsorbent Polymer Microspheres Prepared with Hypertonic Saline to Reduce Microsphere Expansion.

Abstract

PURPOSE: To analyze size changes of superabsorbent polymer (SAP) microspheres with the reduced expansion technique, and to evaluate pharmacological advantages of transarterial chemoembolization using cisplatin-loaded SAP microspheres with the reduced expansion technique. MATERIALS AND METHODS: In an in vitro study, diluted contrast materials containing different concentrations of sodium ions were examined to expand SAP microspheres and determined the reduced expansion technique. Size distributions of cisplatin-loaded SAP microspheres were analyzed. In an in vivo study, TACE was performed using cisplatin-loaded SAP microspheres with the reduced expansion and control techniques in 18 VX2 rabbits. RESULTS: The degree of expansion was reduced to the greatest extent by using a mixture of non-ionic contrast material and 10% NaCl at a 4:1 ratio. The mean diameter of the reduced expansion of cisplatin-loaded SAP microspheres was 188.4 μm, while that of the control expansion was 404.9 μm. The plasma platinum concentrations of the reduced expansion group at 5 min after TACE were significantly higher than those of the control expansion group (2.19 ± 0.77 vs. 0.75 ± 0.08 μg/mL, P = .01). The tumor platinum concentrations of the reduced expansion group at 1 h were significantly higher than those of the control expansion group (10.76 ± 2.57 vs. 1.57 ± 0.14 μg/g, P = .044). CONCLUSION: The expanding level of SAP microspheres can be reduced by using hypertonic saline. Cisplatin-loaded SAP microspheres with the reduced expansion technique have the advantages of achieving higher cisplatin tissue concentration in TACE for liver tumors.