In vivo evaluation of cisplatin-loaded superabsorbent polymer microspheres for use in chemoembolization of VX2 liver tumors.

Purpose: To investigate the pharmacokinetics and efficacy of chemoembolization with a cisplatin-loaded superabsorbent polymer (SAP) suspension in a rabbit model with transplanted liver VX2 tumors.

Materials And Methods: VX2 tumors were implanted into the left lobe of the liver in eight rabbits. Embolization of the proper hepatic artery was performed with cisplatin-loaded or unloaded SAP. In the cisplatin-loaded SAP group (n = 4), 5 mg of SAP (106-150 μm) loading 2.35 mg of cisplatin and 0.5 mL of ionic contrast material (ioxaglic acid 320 mgI/mL) was injected into the proper hepatic artery. In the control group (hepatic arterial infusion [HAI] + SAP; n = 4), 5 mg of SAP loading 0.5 mL of ioxaglic acid alone was injected after a bolus infusion of an equivalent amount of cisplatin. Sequential change of the plasma platinum concentration within the first 24 hours was measured. Blood sampling and histopathologic examination were performed at 1-week follow-up. Magnetic resonance (MR) images were used to calculate the growth rate of the VX2 tumor.

Results: All animals underwent successful embolization. Both total and free plasma platinum mean concentrations within the first 24 hours remained lower in the cisplatin-loaded SAP group, although without statistical significance (P > .05). The mean tumor growth rate was significantly lower in the cisplatin-loaded SAP group than the control group (20% vs 116%; P = .049). Histopathologic examination revealed coagulative necrosis to nontumorous liver parenchyma in two rabbits in the cisplatin-loaded SAP group, although no deaths occurred.

Conclusions: These results suggested that chemoembolization with cisplatin-loaded SAP was a safe and tolerable treatment and was more effective in suppressing the tumor growth.