Title: Formation and Development of Liposomes Encapsulated Radiotracer and Assisting the Uptake of Imaging Studies
Liposomes are closed and spherical,l with one or more lipid bilayers, which form an internal cavity that can carry aqueous solutions. Llipid bilayers are composed of two sheets of tightly arranged phospholipids. The ability of liposomes to function as a drug delivery system can be affected by the number and rigidity of the lipid bilayers, as well as their size and surface charge, lipid organization, and surface modification. An animal-stage study of nanoparticle agents with 99mTc aimed to assist in the biophysical characterization and biodistribution of 99mTc labeled with nanoparticles, with the additional aim of demonstrating its toxicity, clearance, distribution, safety, and effectiveness. A further aim was to develop various techniques in order to reduce the size of the nanoparticles, as well as testing the zeta potential, while adding cationic particles to enhance the drug encapsulation. New Zealand rabbits were included in this study after being anesthetized with 2:1 ketamine/xylazine intramuscularly. Neutral liposomes were used in addition to the cationic nanoparticles. Baseline levels were determined to compare the new agents using nanoparticles with tracers without nanoparticles. Static and dynamic images with matrix size of 256x1024 were acquired, using a Symbia gamma camera immediately and one hour after intravenous injection. The biodistribution then was tested by obtaining the count rate of each organ and calculating the organ/organ ratio; the clearance was also studied. Both the neutral and the cationic nanoparticle agents showed fast clearance, as well as better targeting and localization in the organs, compared to the 99mTc tracer without nanoparticles. Further research will aim to test other nanoparticles of different types, with different surface chemistries, surface modifications, and sizes, to support these investigations.