Liposomes, spherical-shaped nanovesicles, were discovered in the 60ies by Bangham. Since that, they were extensively studied as potential drug carrier. Due to their composition variability and structural properties, liposomes are extremely versatile leading to a large number of applications including pharmaceutical, cosmetics and food industrial fields. This bibliographic paper offers a general review on the background and development of liposomes with a focus on preparation methods including classic (thin film hydration, reverse-phase evaporation, ethanol injection…) and novel scalable techniques. Furthermore, liposome characterization techniques including mean size, zetapotential, lamellarity, encapsulation efficiency, in vitro drug release, vesicles stability and lipid analysis synthesized from different published works are reported. The current deepening and widening of liposome interest in many scientific disciplines and their application in pharmaceutics, cosmetics and food industries as promising novel breakthroughs and products were also handled. Finally, an opinion on the usefulness of liposomes in various applications ranging from unsubstantiated optimism to undeserved pessimism is given. The obtained information allows establishing criteria for selecting liposomes as a drug carrier according to its advantages and limitations.

In this article, a hydrophobic (beclomethasone dipropionate; BDP) and a hydrophilic (cytarabine; Ara-C) drugs have been encapsulated in liposomes in order to be administered via the pulmonary route. For this aim, a liposome preparation method, which is easy to scale up, the ethanol injection method, has been selected. The effects of critical process and formulation parameters have been investigated. The drug-loaded liposomes were prepared and characterized in terms of size, zeta potential, encapsulation efficiency, release study, cell uptake, and aerodynamic behavior. Small multilamellar vesicles, with sizes ranging from about 80 to 170 nm, were successfully obtained. Results indicated a significant influence of phospholipid and cholesterol amounts on liposome size and encapsulation efficiency. The higher encapsulation efficiencies were about 100% for the hydrophobic drug (BDP) and about 16% for the hydrophilic one (Ara-C). The in vitro release study showed a prolonged release profile for BDP, in contrast with Ara-C, which was released more rapidly. The cell-uptake test revealed that fluorescent liposomes have been well internalized into the cytoplasm of SW-1573 human lung carcinoma cells, confirming the possibility to use liposomes for lung cell targeting. Nebulized Ara-C and BDP liposomes presented aerodynamic diameters compatible with deep lung deposition. In conclusion, the elaborated liposomes seem to be promising carriers for both Ara-C and BDP pulmonary delivery.

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