Contrast material-carrying liposomes: biodistribution, clearance, and imaging characteristics.

Purpose: To assess the biodistribution, clearance, and computed tomographic (CT) imaging characteristics of interdigitation-fusion (IF) liposomes that carry iotrolan in their aqueous phases.

Materials And Methods: Biodistribution and clearance of liposomes containing iotrolan produced with the IF method (IF vesicles) were assessed in rats. CT scans of rats and dogs were obtained after injection of IF vesicles at 100 and 250 mg of iodine per kilogram of body weight.

Results: A high initial uptake (63%-96% of the injected dose) was found in the liver and spleen. Liver elimination showed half-lives to be 12.9 days at 250 mg of iodine per kilogram, 10.9 days at 100 mg, and 8.7 days at 25 mg. At 250 mg of iodine per kilogram, the rats had an average of 96 HU of hepatic and 321 HU of splenic enhancement. The dogs had 116 HU of hepatic and 65 HU of splenic enhancement.

Conclusion: IF liposomes have favorable biodistribution, clearance, and imaging characteristics as hepatosplenic contrast agents.