News & Press
Chemistry Today Magazine – March/April 2020, VOL. 38(2)
Liposomes are artificial membranes, in most cases composed of phospholipids like phosphatidylcholines (PC), phosphatidylethanolamines (PE) and phosphatidylserines (PS), enclosing an aqueous compartment. They form spontaneously when phospholipids are placed in an aqueous environment, because of their dual preference to solvents, which was first described by Bangham and Horne in 1962 . Amphiphilic lipids consist of one lipophilic part that is soluble in nonpolar solvents, and a hydrophilic part soluble in polar solvents. Liposomes can be classified according to their structural properties or to their preparation method [2,3].
An advantage of liposomes as efficient drug delivery systems is the possibility that both hydrophilic and lipophilic molecules can be entrapped into either the aqueous core or lipid bilayer . Due to their structure and the employed lipid molecules, liposomes are biocompatible, biodegradable and relatively non-toxic .
The application of liposomes as drug carriers and pharmaceutical products depends on their colloidal stability, chemical composition, and microencapsulation / surface properties. The classification of liposomal products range from drug-dosage forms  and cosmetic formulations , to diagnostics  and various applications in the food industry . In drug delivery applications, they have been extensively investigated for the delivery of anti-tumor substances , antimicrobial agents for treatments of bacterial , viral  and parasitic-induced diseases , and for use as immunological adjuvants for vaccines  and cytotoxics (e.g. doxorubicin). Other studies demonstrated the entrapment of genes  and DNA  into liposomal systems. Currently, many clinical studies for liposomal preparations are under investigation, and several products have already entered the market (Figure 1).