Azone can increase the fluidity of lipids, thereby changing the permeability of the stratum corneum of the skin and reducing the diffusion resistance of drugs. The abdominal skin of the experimental mice was coated with the water extract of Bupleurum Jierefang plus 2% azone. After 8 hours, the mice were sacrificed. The ultrastructure of the coated skin was observed with a KYYY-1000B scanning electron microscope, and the stratum corneum cells were loose. It is slightly damaged, the cracks on the skin surface are increased, and the diameter of the follicle pores is widened, which is conducive to the penetration of drugs into the skin. Azone has different effects on the transdermal absorption of different drugs, and has different degrees of permeation-promoting effect on water-soluble drugs, while the permeation-promoting effect on some lipid-soluble drugs is not obvious, and may even have a negative effect. The usual concentration of azone is less than 10%, it is not that the higher the concentration, the stronger the effect of promoting transdermal absorption, and the opposite effect will be obtained if the dosage is too large. The optimal osmotic concentration is related to the physicochemical properties of the drug and the dosage form of the preparation.
Azone has strong permeation-promoting effect on water-soluble drugs, low toxicity and high safety, and is one of the most commonly used gel permeation enhancers. There are two types of azone on the market today: water-soluble and fat-soluble. The water-based gel matrix is hydrophilic, so that the water-soluble azone can be easily distributed into the intercellular parts and exert its permeation-promoting effect. Too high azone concentration will increase the viscosity of the gel, which is not conducive to the transdermal absorption of the drug in the gel. In vitro studies of adding 2.0% or 3.0% azone to 3.0% chitosan gel of celecoxib showed that it had the best adhesion properties and mucosal retention time, but with the concentration of chitosan and azone increased, the amount of celecoxib delivered by oral administration decreased.
Azone is widely used as a penetration enhancer in creams. Fu Jiyu et al.  found that the penetration rate of ibuprofen cream samples with different concentrations of azone was generally greater than that of cream samples without azone; and when the concentration of azone was 3%, the ibuprofen The penetration rate was the highest, and the cumulative penetration rate in 12 h reached (48.8±7.62)%. Studies have shown that different concentrations of azone can promote the transdermal absorption of manidipine cream to a certain extent, and the order of its permeation-promoting effect within 24 hours is: 3% azone > 5% azone > 1% azone > Azone-free.
Patches are often used in Chinese medicine transdermal therapy, and select relevant parts or acupoints for transdermal administration. Investigate the permeation rate and total amount of tobemoside A in the Jingliukang plaster with the dosage of 0, 1%, 2% and 3% of azone. More, it is 4.5 to 4.9 times that of adding azone to 0, and adding 1% azone is the best. Under the action of different penetration enhancers, the transdermal penetration rate of 6-gingerol in the ginger gel patch was as follows: 4% azone>2% propylene glycol+2% azone>4% menthol>4% borneol>control, It is shown that the permeation-promoting effect of azone is the most significant; at the same time, after optimization, it is concluded that the permeation-promoting effect is: 6% azone>4%azone>2%azone>1%azone, and adding 4%～6% nitrogen The penetration rate of the drug in ketones is similar.