How do you prepare liposomes?
All the methods of preparing the liposomes involve four basic stages:
- Drying down lipids from organic solvent.
- Dispersing the lipid in aqueous media.
- Purifying the resultant liposome.
- Analyzing the final product.
How are MLV liposomes made?
There are four types of liposomes: MLV (multilamellar vesicle), SUV (small unilamellar vesicle), LUV (large unilamellar vesicle), and MVV (multivesicular vesicle). These vesicles are formed by forcing hydrated lipids through pores (extrusion) or by sonicating the lipid solution.
How do you purify liposomes?
The typical types of centrifugations for liposome purification include differential centrifugation, density gradient centrifugation, and centrifugation through molecular sieves (Torchilin and Weissing 2002). Differential high speed centrifugation is quite useful for separating large liposomes from liposome mixtures.
How do you load a drug into a liposome?
In general, liposomal drug loading is achieved by either passive or active methods (9, 19–22). Passive loading involves dissolution of dried lipid films in aqueous solutions containing the drug of interest. This approach can only be used for water-soluble drugs, and the efficiency of loading is often low.
How do liposomes concentrate?
Large liposomal particles can be concentrated using centrifugation. The lowest speed possible to achieve pelleting is best since higher speeds could induce deformation and/or fusion of particles. Centrifugation is only possible with larger particles (>100nm).
How do you make multilamellar vesicles?
Preparation of Multilamellar Vesicles (MLVs)
- Dissolve the lipids in chloroform.
- Combine the lipids in the appropriate ratio.
- Carefully evaporate the organic solvent using a dry nitrogen stream.
- Resuspend the lipid mixture in cyclohexane.
- Freeze the cyclohexane solution using dry ice.
What is involved in the active and passive loading of liposomes with drugs?
The two major methods for liposomal drug loading. (A) Passive loading involves co-current loading and liposomal formation. (B) In active loading, liposomes are formed containing a gradient used to load drugs. An accumulation of catecholamine molecules in the core of the liposomes was observed.