Liposomes have been widely reported as carriers for transdermal delivery of biological drugs, such as insulin, interferon, collagen, heparin, superoxide dismutase, tissue growth factor, etc. The main material of liposomes is phospholipids. Phospholipid molecules form a bilayer under certain conditions, which has the same structure as the lipid bilayer in the intercellular space of the stratum corneum. It is speculated that this structure is conducive to the affinity between the two, thereby improving the drug. penetration rate.
Transdermal delivery body is a kind of nanoliposome prepared from lipid material. In addition to its small size, the more important feature of this carrier is that it is highly deformable. Under a certain hydration pressure (derived from the evaporation of liquid water on the skin surface and the water concentration gradient at each layer of the skin), its lipid film can deform. Experimental studies have reported that this carrier can inject insulin into the body and reach the level of subcutaneous injection. It has a rapid blood sugar lowering effect, but liposomes of the same size cannot carry the drug through.
The iontophoresis method can increase the skin permeability of ion drugs. Under certain electric field conditions, ion drugs enter the skin through pores, sweat glands and other channels through mechanisms such as conductivity, electroosmosis and solvent traction. Using ions Methods of introducing conjugated liposomes can also drive liposomes into the stratum corneum. Different from ion conduction, the electroporation method is a method of forming temporary hydrophilic micropores in the stratum corneum of the skin under the action of high voltage pulse current to increase the penetration of drugs.