**5.4 The sonication method**

The sonication method is the most used method for the preparation of liposomes (unilamellar). Both techniques are *probe sonication*, in which the tip sonicator is directly immersed into the liposome. Dispersion is high and there is overheating, so the vessel is submerged in an ice bath. With this technique, up to 5% of the lipids can be de-esterified after 1 h. The *bath sonicator* is the second type of sonication method, and the dispersion of liposomes in a tube is placed into a bath sonicator. The regulation of the temperature is easier, and the lipid bilayer of liposomes can fuse with other bilayers, thus delivering the liposomal contents. By making liposomes within drug solutions, they can be delivered past lipid bilayers.
