Preparation, characterization, and biodistribution study of technetium-99m-labeled leuprolide acetate-loaded liposomes in ehrlich ascites tumor-bearing mice

Abstract

ABSTRACTby gamma scintigraphic studies. The findings demonstrate the distribution of these liposomes within solid tumor and prove that the sterically stabilized liposomes experience increased tumor uptake and prolonged circulation half life. Hence these findings will be relevant for the optimal design of long circulating liposomes for the peptide drugs and for targeting of liposomes toward tumor.The purpose of this study was to prepare conventional and sterically stabilized liposomes containing leuprolide acetate in an attempt to prolong the biological half life of the drug, to reduce the uptake by reticuloendothelial system (RES), and to reduce the injection frequency of intravenously administered peptide drugs. The conventional and sterically stabilized liposomes containing leuprolide acetate were prepared by reverse phase evaporation method and characterized for entrapment efficiency and particle size. Radiolabeling of leuprolide acetate and its liposomes was performed by direct labeling with reduced technetium-99m. Its biodistribution and imaging characteristics were studied in ehrlich ascites tumor (EAT)-bearing mice after labeling with technetium-99m. The systemic pharmacokinetic studies were performed in rabbits. A high uptake by tumor was observed by sterically stabilized liposome containing leuprolide acetate compared with free drug and conventional liposomes. The liver/tumor uptake ratio of free drug, conventional (LL), and sterically stabilized liposomes (SLL5000 and SLL2000) was found to be 20, 7.99, 1.63, and 1.23, respectively, which showed the increased accumulation of sterically stabilized liposomes in tumor compared with the free drug and conventional liposomes at 24 hours postinjection. Liver uptake of sterically stabilized liposomes was still 7-fold less than the conventional liposomes. The marked accumulation of liposomes in the tumor-bearing mice was also documented

Antibody Library-based Tumor Endothelial Cells Surface Proteomic Functional Screen Reveals Migration-stimulating Factor as an Anti-angiogenic Target

“…Biodistribution analysis was performed as described previously (18). Tumor-bearing mice were anesthetized and injected via the tail vein with 99m Tc-labeled antibody (2 g IgG, 60 Ci/g).…”

Etoposide-incorporated tripalmitin nanoparticles with different surface charge: Formulation, characterization, radiolabeling, and biodistribution studies

“…Our recent reports showed success in the formation of stable radiolabeled complexes of drugs and liposomes. 25,28,29 We hereby report our experience to formulate etoposide-incorporated, negatively charged tripalmitin nanoparticles (ETN) and positively charged tripalmitin nanoparticles (ETP) using stearyl amine by melt emulsification and high-pressure homogenization, and their characterization by particle size analysis, zeta potential measurements, and scanning electron microscopy (SEM). The drug and nanoparticles were radiolabeled with 99m Tc and their in vitro stability was evaluated.…”

A gamma scintigraphy study to investigate uterine targeting efficiency of raloxifene-loaded liposomes administered intravaginally in New Zealand white female rabbits

“…This mixture was added to 5 mL of RLH solution (1 mg/ mL, in hydro-alcoholic mixture (6:4)) and incubated for 10 to 15 minutes at room temperature. Percentage labeling efficiency and stability of the labeled complexes was assessed (Arulsudar et al, 2004;Movva et al, 2008).…”