An Investigation of Membrane-Encapsulated Trypanocides.
Annual rept. 16 Jan 79-15 Jan 80,
WASHINGTON UNIV SEATTLE
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A new method which is capable of entrapping 111 In 3 in any types of liposomes with an efficiency of 80 about 90 has been developed. There are no differences in the physical properties and biodistribution between the liposomes encapsulating 111 In 3 by this new loading method and that by the conventional method of encapsulation. Hepatic degradation of sphingomyelincholesterol 21 MM unilamellar liposomes is investigated by the combined approaches of perturbed angular correlation of gamma radiation and kinetic modeling. The hepatic degradation of the SMCH21 MM unilamellar liposomes in vitro at 37 C follows the first order kinetics with a half-life of 3.5 or - 0.2 hours. However, the rate of the in vivo degradiation of liposomes in the liver of a mouse is found to be 4.3 or - 0.2 hours. The rate of release of the liposome-encapsulated agent, indium-111, in the liver, is not constant and reaches a maximum at about 8 hours after the administration of liposomes. The potential carrier application of serum protein-lipid vesicles is found to be limited. However, the SMCH 21 MM unilamellar liposomes is found to be an excellent carrier with a blood clearance half-life of about 16.5 hours. This is by far the longest clearance time ever reported for liposomes of natural sources.
- Medicine and Medical Research