Solvent-based proliposomes

ProUposome technologies have been introduced as a potentially applicable resolution to the stability problems of liposomes. Proliposomes are phospholipid preparations that generate liposomes by addition of aqueous phase and shaking. Proliposomes can be classified into two types particulate-based proliposomes [48] and solvent-based proliposomes [49],... 

Depending on preparation conditions, liposomes generated from solvent-based proliposomes have been danonstrated to be OLVs [49], MLVs [64], a mixture of MLVs and OLVs [65,66], or, under static conditions, LUVs with the occasional presence of MLVs [67],... 

Particulate-based proliposomes are soluble carrier (e.g., carbohydrate) particles coated with phospholipids. The addition of aqueous phase results in the formation of MLVs [48,50], On a small scale, particulate-based proliposomes are made by placing the carrier particles in a round-bottomed flask. The flask is attached to a modified rotary evaporator with feed line. A chlorofonnic solution of lipid is coated dropwise onto the carrier particles via the feed line under reduced pressure. Solvent evaporation produces proliposomes which can be either hydrated innnediately by addition of aqueous phase, or stored in the freezer for future use. 

Solvent-based prohposomes are also referred to as alcohol- or ethanol-based proliposomes when ethanol is used as the solvent. Ethanol-based proliposomes are concentrated ethanohc solutions comprising phospholipid, ethanol, and aqueous phase (5 4 10 w/w/w). This proliposome mixture generates liposomes on dilution with aqueous medium [49]. The coexistence of ethanol and aqueous phase with phospholipids in this ratio has been shown to form stacked (precipitated) bilayers which generate liposomes when more aqueous phase is added [49]. 

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