Figure 1.

Categories and structures of liposomal drug delivery system. (a) Structural illustration of liposome composition. The size of a typical phospholipid bilayer is 4.5 nm, which is much smaller than the one of the inner aqueous core; (b) Classification of liposomal vesicles according to their lamellarity/compartment and particle size; (c) The size and lamellarity of different types of liposomes; (d,e) The cryo-transmission electron microscopy of Doxil [35] and Vyxeos [36]; (f,g) The electron micrographs of DepoFoam^TM particles with a typical diameter of 1–100 μm (e.g., DepoCyt) and MLVs with a typical diameter of 0.2–5 μm (e.g., Mepact) [37].