Optimizing Druggability through Liposomal Formulations: New Approaches to an Old Concept

Abstract

Developing innovative delivery strategies remains an ongoing task to improve both efficacy and safety of drug-based therapy. Nanomedicine is now a promising field of investigation, rising high expectancies for treating various diseases such as malignancies. Putting drugs into liposome is an old story that started in the late 1960s. Because of the near-total biocompatibility of their lipidic bilayer, liposomes are less concerned with the safety issue related to the possible long-term accumulation in the body of most nanoobjects currently developed in nanomedicine. Additionally, novel techniques and recent efforts to achieve better stability (e.g., through sheddable coating), combined with a higher selectivity towards target cells (e.g., by anchoring monoclonal antibodies or incorporating phage fusion protein), make new liposomal drugs an attractive and challenging opportunity to improve clinical outcome in a variety of disease. This review covers the physicochemistry of liposomes and the recent technical improvements in the preparation of liposome-encapsulated drugs in regard to the scientific and medical stakes.

Liposomes as nanomedical devices

“…13 Finally, the use of phosphatidylcholine with saturated fatty acyl chains and materials that stretch the transition temperature beyond 37°C offered even greater stabilization. 14 For prolongation of the in vivo liposome circulation time, a milestone is the inclusion of hydrophilic carbohydrates or polymers, such as monosialoganglioside (G M1 ) and PEG in liposome composition. G M1 decreases the blood proteins absorbed on the liposomal surface and improves the half-life of liposomes in the blood.…”

Liposome and Their Applications in Cancer Therapy

“…This decreases the possibility for premature leakage of encapsulated components; however, considerations must be made to ensure that encapsulated drugs can still escape the liposomes once they reach the target site of action. On the other hand, if the phase transition temperature of the selected phospholipids is too high, denaturation of the encapsulated drugs may occur during the sizing, or loading processes (Bitounis et al 2012;Laouini et al 2012;Jing Li et al 2015). Therefore, a good balance must be met to guarantee that the selected lipids have phase transition temperatures that prevent premature leakage of components but enable processing to occur at temperatures that are harmless to all liposomal components.…”

“…The phase transition temperature is defined as the temperature at which the lipid physical state converts from an ordered gel phase to a disordered liquid crystalline phase. The conversion of phases depends on hydrocarbon chain length, degree of saturation, charge, and head group species (Bitounis et al 2012;Laouini et al 2012;Bozzuto and Molinari 2015).…”

“…Liposomes are biodegradable, biocompatible, and stable in colloidal solutions (Akbarzadeh et al 2013;Allen and Cullis 2013). Liposomes protect the drug from degradation and reduce drug-related nonspecific toxicity and can be produced and formulated easily for the target specific delivery (Bitounis et al 2012;Bozzuto and Molinari 2015).…”

Liposomes and nanotechnology in drug development: focus on neurological targets

“…These are molecules formed by noncovalent binding of their components which can self-assemble spontaneously and reversibly into organized structures under specific environmental conditions, eg, temperature, pH, and polarity of the medium. 15 Changes in environmental conditions usually result in disaggregation of the molecular units that form the particle. This may represent an advantage, eg, enabling release of a drug load in specific environments, such as a sudden drop in tissue pH, as occurs in ischemic brain tissue after lactic acidosis, or be a disadvantage, eg, the molecule may disintegrate before reaching its target.…”