Turánek and coworkers [63, 64] have developed a sterile liposome production procedure based on this method. Reproducible liposome preparation is feasible in a controlled manner by exact controlling of the dilution rate and process temperature. Additionally, the authors claim their method as being easy to scale up, which makes this method an alternative approach for the production of liposomes for clinical application.

4.3. Reverse-Phase Evaporation (REV) Similarly to the above Inhibitors,research,lifescience,medical presented injection methods, lipid is hydrated via solubilization in an organic phase followed by introduction into an aqueous phase. The organic phase should be immiscible with the aqueous phase, thus an oil/water emulsion is created, which is diluted Inhibitors,research,lifescience,medical with further aqueous phase for liposome formation [65]. The advantage of this very popular preparation MEK inhibitor technique is a very high encapsulation rate up to 50%. One variation of the microemulsion technique, the double emulsion technique, further improves the encapsulation rates and results in unilamellar liposomes [26]. A possible drawback of this efficient method is the remaining solvent or the proof of their absence especially Inhibitors,research,lifescience,medical for using them for pharmaceutical

purposes. The other important issue is large-scale production which might be feasible if appropriate shear mixing devices for the creation of the microemulsion and pumps Inhibitors,research,lifescience,medical for the dilution step are available. 5. Methods Based on Detergent Removal In this group of liposome preparation procedures, detergents, such as bile salts or alkylglycosides, are used for the solubilization of lipids in micellar systems. In contrast to lipids, detergents are highly soluble in both aqueous and organic

media. There is equilibrium between the detergent molecules in the aqueous phase and the lipid environment of the micelle. The size and shape of the resulting vesicles are depending on the chemical nature of the detergent, their concentration, and the lipids used. To date, the most frequently applied method for membrane protein reconstitution Inhibitors,research,lifescience,medical involves the cosolubilization of membrane proteins Sodium butyrate and phospholipids [66–68]. Common procedures of detergent removal from the mixed micelles are dilution [69], gel chromatography [70], and dialysis through hollow fibers [71] or through membrane filters [72]. Additionally, detergents can also be removed by adsorption to hydrophobic resins or cyclodextrins [73]. Dialysis of mixed micelles against an aqueous medium was first described by Kagawa and Racker [74]. This method for vesicle formation is based on the retention of the micelle, whereas free detergent molecules are eliminated. Goldin [72] describe the use of pure cellulose for this approach. In order to gain better control in the formation of proteoliposomes, Wagner et al.