Prolonged circulation

Gabizon, A., and Papahadjopoulos, D. (1988). Liposome formulations with prolonged circulation time in blood and enhanced uptake by tumors, Proc. Natl. Acad. Sci. USA, 85, 6949-6953. 

Gabizon A, Catane R, Uziely B, et al. Prolonged circulation time and enhanced accumulation in malignant exudates of doxorubicin encapsulated in polyethylene-glycol coated liposomes. Cancer Res 1994 54 987-992. 

Allen TM, Hansen C, Martin F, Redemann C, Yau-Young A. Liposomes containing synthetic lipid derivatives of poly(ethylene glycol) show prolonged circulation half-lives in vivo. Biochim Biophys Acta 1991 1066 29. 

Figure 4 A set of gamma camera images of a rabbit intravenously injected with Tc-99m-LEH. Twenty-five percent of blood was exchanged with liposome-encapsulated hemoglobin (LEH) (hypovolemic) and the animal was imaged using a gamma camera at various times after infusion. The images clearly show a prolonged circulation of LEH as evidenced by the continued grayscale intensity in heart.

Maruyama K, Yuda T, Okamoto A, et al. Prolonged circulation time in vivo of large unilamelar liposomes composed of distearoyl phosphatidylcholine and cholesterol containing amphipathic poly(ethylene glycol). Biochim Biophys Acta 1992 1128 44. 

The three commercially available AmB formulations differ in their morphology, their composition, and, consequently, their biological activity. AmBisome (developed by Nexstar Pharmaceuticals, commercially available from Gilead Sciences) is a true liposome formulation, consisting of small, unilamellar vesicles (9). Their small size confers a prolonged circulation time... 

Figure 1.1. Schematic representation of four major liposome types. Conventional liposomes are either neutral or negatively charged. Stealth liposomes are sterically stabilized and carry a polymer coating to obtain a prolonged circulation time in the body. Immunoliposomes are antibody targeted liposomes and can consist of either conventional or sterically stabilized liposomes. Positive charge on cationic liposomes can be created in various ways. Reproduced from reference [112] with permission.

Allen, T.M., Hansen, C., and Rutledge, J. (1989) Liposomes with prolonged circulation times factors affecting uptake by reticuloendothelial and other tissiSachim. Biophys. Acta, 981 27-35. 

Kwon. G. S., S. Suwa, M. Yokoyama, T. Okano, Y. Sakurai, andK. Kataoka. 1994. Enhancedtumoraccumulation and prolonged circulation times of micelle-forming polyethylene oxide-aspartate) block copolymers-adriamycin conjugatesl. Control. Rel29 17-23. 

M.S. Newman, L.S. Guo, M.C. Pedroso de Lima, and N. Duzgunes. 1997. Sterically stabilized pH-sensitive liposomes. Intracellular delivery of aqueous contents and prolonged circulation in vivo./. Biol. 

Experimental pharmacological investigations into selected acyl enzymes have shown that, besides the depot effect of the modified enzymes, their elimination characteristics changed as did, in some cases, their specific effect, m particular, as for as fibrinolytic enzymes are concerned, acylation could be shown to modify significantly the clearance of these enzymes. The prolonged circulation of... 

Sterically stabilized ( stealth ) liposomes, which carry hydrophilic coatings, are used to obtain prolonged circulation times. 

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