Liposomes drug retention

Boman NL, Masin D, Mayer LD, Cullis PR, Bally MB. Liposomal vincristine which exhibits increased drug retention and increased circulation longevity cures mice bearing P388 tumors. Cancer Res 1994 54 2830. 

Shelf life Shelf-life issues that need to be addressed include avoidance of pre-administration leakage of the liposome-associated drug (retention loss), size stability (occurrence of fusion or aggregation) and phospholipid degradation (occurrence of peroxidation and hydrolysis). 

A commonly used strategy to prepare a liposome-based NIR-responsive vehicle, while optimizing liposome composition and structure to enhance circulation time and drug retention, is to incorporate Au nanostructures into the thermally sensitized liposome membranes. On NIR irradiation, Au nanostructures, such as nanoshells, nanorods or NPs, convert NIR light into heat, increasing the permeability of the liposome membrane via a photothermal conversion process. Finally, the anticancer drugs or genes are released from the liposomes. 

Kim et al. (1987) showed that the prolonged retention time of Ara-C in the peritoneal cavity after intraperitoneal administration of the drug in liposomal form as discussed above resulted in better therapeutic effects on intraperitoneally inoculated L1210 cells, as compared to the free drug. The activity of intraperitoneally administered cDDP on Ehrlich ascites carcinoma in mice was increased after encapsulation in neutral liposomes (Sur et al., 1983). The in vivo studies revealed improved antitumor activity and a lower toxicity sifter administration of cDDP liposomes compared to free drug. 

Gregoriadis, G. (1988a). Fate of injected liposomes Observations on entrapped solute retention, vesicle clearance and tissue distribution in vivo, in Liposomes as Drug Carriers Recent Trends and Progress (G. Gregoriadis, ed.), John Wiley and Sons, Chichester, pp. 3-18. 

Hunt, C. A., Rustum, Y. M., Mayhew, E., and Papahadjopoulos, D. (1979). Retention of cytosine arabinoside in mouse lung following intravenous administration in liposomes of different size, Drug Metabol. Dispos., 7, 124-128. 

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