Evaluation of sterically stabilized liposomes as a vehicle for targeting technetium-99m labelled radiopharmaceuticals.
Sterically stabilized neutral liposomes (multilamellar vesicles) were prepared by sonicating phosphatidylcholine and cholesterol (molar ratio 4:1) film in phosphate buffered saline (50 mM, pH 7.4) containing 4% Tween 20. Tc-99m-GHA was incorporated in these liposomes by treating 0.5 ml of the suspension with lyophilized GHA kit (5 mg GHA and 250 micrograms SnCl2 x 2 H2O) followed by addition of 1 ml 99mTcO4- (1-3 mCi). The labelling yield was 60-70%. Tween 20 has provided significant stability of the radiolabel as compared to that without its addition, when radiolabelled liposomes were incubated in serum up to 24 h. With respect to Tc-99m-GHA alone, radiolabelled liposomes exhibited 4- to 6-fold greater radioactivity in the blood of rabbits (15 min-24 h). Comparison of biodistribution data of radiolabelled liposomes and Tc-99m-GHA in mice demonstrated a 10- to 12-fold greater hepatic accumulation of radiolabelled liposomes with respect to that of Tc-99m-GHA throughout the period of study (15 min-24 h), though their concentration in the kidneys was comparable.
Kumar
S
S
Department of Pharmaceutics, Faculty of Pharmacy, Hamdard University, New Delhi, India.
Singh
T
T
Khar
R K
RK
Sharma
S N
SN
Chauhan
U P
UP
D000818:Animals; D002784:Cholesterol / Q000737:chemistry; D004337:Drug Carriers; D008081:Liposomes; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D015609:Organotechnetium Compounds / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D010713:Phosphatidylcholines / Q000737:chemistry; D011136:Polysorbates; D011817:Rabbits; D013400:Sugar Acids / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D013667:Technetium / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D014018:Tissue Distribution
D004337:Drug Carriers; D008081:Liposomes; D015609:Organotechnetium Compounds; D010713:Phosphatidylcholines; D011136:Polysorbates; D013400:Sugar Acids; D013667:Technetium; D002784:Cholesterol; C100014:technetium Tc 99m gluceptate