Liposome-encapsulated drugs biodistribution

Liposomal encapsulation or incorporation in a lipid complex can substantially affect a drug s functional properties relative to those of the unencapsulated or nonlipid-associated drug. Lipid-based formulations increase the circulation time and alter the biodistribution of associated amphotericin. Increasing drug levels at site of action and reducing levels in normal tissues offers 2 distinct clinical advantages An increased therapeutic index and altered toxicity profile relative to free drug. 

However, the administration of free doxorubicin often leads to dose-limiting side effects such as cardiotoxicity and myelosu-pression. This toxicity can be reduced by liposomal encapsulation of doxorubicin because of the modified biodistribution of the drug (1). Additionally, the efficiency of the drug is improved due to the passive targeting effect of liposomes. 

Liposomes have been used in the local delivery of drugs to the oral mucosa. Farshi et al. [96] studied the biodistribution of dexamethasone sodium phosphate (DSP) encapsulated in multilamellar vesicle (MLV) liposomes labeled with 99mTc in ulcerated and intact oral mucosae of rats. The liposomes were found to localize the drug in the ulcerated area and increase local drug concentration while decreasing systemic concentration. 

The encapsulation of these anthracycline cytostatics in liposomes effects a modified biodistribution of the drug the drug is distributed away from the heart, where it can exert considerable toxic effects, and is preferentially taken up by solid tumor tissue. 

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