What techniques are used for liposome preparation?

There are several techniques used for liposome preparation. The thin-film method is a popular technique for preparing liposomes. It involves creating a thin layer of lipids on the inside surface of a rotary evaporator flask. This lipid film is then hydrated with a water or buffer solution to form liposomes. Another method is the proliposome method, which is one of the easiest ways to produce liposomes. Unlike the thin-film method, it tends to be less consistent when making small amounts of liposomes, but it offers much better encapsulation efficiency. This technique involves dissolving lipids in a mixture of water and ethanol, while stirring at 60 °C for approximately 10 minutes, to produce a uniform lipid mixture. Another technique is the ethanol injection method. This technique is used to create liposomes with sizes between 30 and 170 nm, typically producing small unilamellar vesicles (SUVs). The final size of the liposomes depends on the lipid concentration and the rate of injection. In this process, lipids dissolved in ethanol are injected into a water phase while stirring, after which the ethanol is removed. Another technique is the ether injection method, where lipids dissolved in ether (or a mixture of diethyl ether and methanol) are gradually introduced into an aqueous phase that contains the substances to be encapsulated. This aqueous phase is heated to a temperature range of 55–65 °C. Lastly, the freeze-drying method is a novel technique that begins with freezing the aqueous solution containing the liposome formulation, followed by removing the ice through sublimation.