Antitumor effect of miriplatin-lipiodol suspension/emulsion using a VX2 liver tumor model

To evaluate the antitumor effects of miriplatin-lipidol suspension and emulsion.Fifty rabbits with VX2 liver tumors were randomly assigned to ten groups. Then, we prepared four types of mixtures: a suspension of lipiodol and miriplatin (ML), an emulsion of miriplatin dissolved with lipiodol and contrast medium (MLC) or saline (MLS), and saline alone (S). Ratios between lipiodol and contrast medium/saline volumes were 1:1/4, 1:1/2, 1:1, and 1:2 respectively. We used the same dose of miriplatin (2 mg/kg) and lipiodol (0.1 ml/kg) in each emulsion and suspension group. After intra-arterial infusion, the tumor growth rate was calculated, and sequential change of the plasma platinum concentration, the platinum concentration in the tumor and in surrounding normal liver tissue was also measured.Among the ten groups, the tumor growth rate was lower in MLC and MLS groups, and the difference between tumor treated with MLS emulsion (ratio 1:1/2) and ML suspension was significant (p = 0.02). The platinum concentration in the normal liver tissue was lower in MLS and MLC groups than in the ML group, and that in the tumor was higher in the MLS and MLC emulsion (ratio 1:1/2) groups.We suggest that miriplatin-lipiodol emulsion may be more effective than suspension.