Stimulus-responsive liposomes for biomedical applications

Abstract

Liposomes are amphipathic lipidic supramolecular aggregates able to encapsulate and carry molecules of both hydrophilic and hydrophobic nature. They have been widely used as in vivo drug delivery systems since long due to their favorable features, such as synthetic flexibility, biodegradability, biocompatibility, low immunogenicity, and negligible toxicity. In recent years, the possibility to introduce chemical modifications on liposomes has paved the way to smart liposome-based drug delivery systems characterized by even more tunable and disease-directed features. In this review, the different types of chemical modifications introduced so far have been highlighted, with a particular focus on internal stimuli-responsive liposomes and pro-drug activation.

A Review of Liposomes as a Drug Delivery System: Current Status of Approved Products, Regulatory Environments, and Future Perspectives

“…The microenvironment at the target disease site can be exploited to trigger the release of drug from liposome carrier. The external or internal stimuli such as temperature, pH, light, eletromagnetic fields, enzyme, and hypoxia, are frequently studied as "on-off" switch of the drug release [151,152]. Although promising results were obtained in pre-clinical studies, it is challenging for successful clinical translation due to the major issues, such as the leakage of the cargo before reaching the target sites, the individual differences among patients, as well as the multi-modal therapies involved.…”

Liposomes: structure, composition, types, and clinical applications

“… ROS leads to high concentration levels of glutathione (GSH) in tumor cells cleaving the liposomal formulations [ 137 , 138 ] Enzyme-responsive liposomes Protease, amidase, and esterase enzymes Based on amides or esters hydrolysis by protease or esterase enzymes release loaded drugs. Decreases the adverse side effects of toxic drugs and enable encapsulation of prodrugs [ 139 , 140 , 141 ] pH-sensitive liposomes pH change Cholesteryl hemisuccinate (CHEMS) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), were used to prepare pH-sensitive liposomes Liposomes with pH-dependent release features [ 142 , 143 , 144 ] …”

Drug delivery strategy in hepatocellular carcinoma therapy

“…As a drug carrier, liposomes have the following advantages: (1) they are mainly comprised of natural phospholipids and cholesterol, which will be biodegraded and will not accumulate in the body, with low immunogenicity; (2) both water-soluble and lipid-soluble drugs can be embedded for delivery, and the drug is slowly released from the liposome for a long time; and (3) through endocytosis and fusion, liposomes can directly deliver drugs into cells, avoiding the use of high concentrations of free drugs and thus reducing adverse reactions ( 157 – 160 ). Liposomes are characterized by biocompatible, flexible formulations, the potential to add targeting moieties, etc.…”