Application of Transfersomes and Ethosomes in Transdermal Drug Delivery

The transfersomes is a self-aggregating vesicle obtained by formulating and improving on the basis of liposomes, also known as flexible nano-liposomes (FNL). It is a lipid carrier obtained by adding surfactants (such as sodium cholate, polysorbate, spaan, sodium deoxycholate, etc.) to liposome materials. It has a high degree of self-deformation and can efficiently pass through skin pores several times smaller than its particle size. The driving force of its penetration into the skin is the hydration gradient and the resulting osmotic pressure difference, which can make the membrane elastically deform and squeeze into the stratum corneum. Widened intercellular space. The particle size of the transfersomes is 90~500nm, the deformability is 5 orders of magnitude larger than that of ordinary liposomes, the transdermal efficiency is high, and the skin penetration rate is as high as 80%. The delivery body can keep more drugs in the skin, reduce the amount of drugs entering the blood circulation, and form drug reservoirs in the epidermis and dermis, so that the drugs can permanently treat the lesions. A laser confocal microscope was used to study the interaction between the fluorescein sodium transfersomes and the skin. Before transdermal penetration, the drug-loaded delivery body first adheres to any part of the skin, and most of it passes through the hair follicle area instead of transdermal absorption through intracellular or intercellular pathways.The transfersomes can be used as a transdermal drug delivery carrier for large molecules, small molecules, lipophilic and hydrophilic drugs.

The in vitro transdermal permeation test of the sinomenine hydrochloride transfersomes proved that the cumulative amount of skin penetration of the drug in the transfersomes was significantly higher than that of ordinary liposomes and aqueous solutions. Compared with the commercially available gel, the concentration of diclofenac delivery body lotion in the muscle, distal skin, muscle, blood, liver, and bladder of the administration site of mice is significantly higher than that of the gel after it is applied to the skin. The transfersomes makes the surface drug concentration the same as the deep part, while the surface concentration is higher than the deep part when the gel is applied. The average particle size of the vincristine transfersomes is 63 nm. Taking vincristine injection as a control, the blood retention time of vincristine transfersomes was prolonged by 12 times, and the lymphatic targeting index of rats increased by 2.75 times, indicating that the transfersomes can better carry vincristine into the systemic circulation through the skin. With good transdermal lymphatic targeting, it can be used as a new lymphatic targeting drug delivery system. The delivery body of hormone drugs can concentrate the drugs in the inflammation site. Insulin transfersomes was coated on the surface of mouse skin in a non-blocking manner. Compared with ordinary insulin liposomes and insulin solution, transfersomes significantly promoted the transdermal insulin transport and had a significant and lasting effect on reducing blood sugar in mice, while the ordinary insulin liposomes and insulin solution did not lower the blood sugar. The transfersomes has a strong affinity with the biofilm. Encapsulating antifungal drugs in the delivery body can improve the antifungal effect. The ketoconazole transfersomes is prepared by the ultrasonic dispersion method combined with the microporous membrane method，the average particle size is 146.7nm, and the deformability is good. When subjected to the difference between the inward hydration pressure and the spontaneous dehydration pressure, efficient permeability can occur. And this deformability increases with the increase of external force. The drug of ketoconazole delivery body has a long elimination half-life, greatly reduced nephrotoxicity, and reduced acute toxicity. It can gather at the infected site, can kill the fungus that is swallowed, and is well tolerated.

Ethosomes
Ethosomes are liposomes containing high concentrations of ethanol, which have strong fluidity and are easy to deform and penetrate the skin barrier. Ethosomes have a strong penetration promoting effect on the percutaneous absorption of hydrophilic and lipophilic molecules, including antifungal drugs, non-steroidal anti-inflammatory drugs, hormones, antiviral drugs, genetic and macromolecular drugs, etc. In the in vitro skin penetration test of ethinyl estradiol, compared with ordinary gels, ethosomes can significantly increase the penetration rate and skin retention of ethinyl estradiol, and prolong the action time of the drug. The ethosomes can also promote the passage of the drug through the skin, and the absorption of the capillary into the systemic circulation. Finasteride steroids ethosomes and liposomes are compared by human skin permeation experiments. The percutaneous penetration rate of the former is 3.2 times that of the latter, and liposomes mainly make drugs accumulate in the epidermal layer, while ethosomes are transported through the skin and allow drugs to enter the dermis and the circulatory system.