Design And Analysis On Microsystem Of Transdermal Drug Delivery With Microneedle-based And Sonophesis

In medical practice,the efficacy of drug treatment depends not only on the drug itself,but also on the way it is administered.Although the traditional oral and injection administration methods are simple and convenient,there are still some problems.For example,when taken orally,due to the digestion of the gastrointestinal tract and the first-pass effect of the liver,drug molecules are easy to be decomposed,resulting in reduced efficacy of drugs.And after taking medicine,the blood concentration changes greatly,which will affect the sustainability of drug efficacy.Injection can avoid side effects of oral administration and improve the efficacy of drugs,but this method requires professional operation.Once improper treatment,it is easy to cause bleeding and infection.In addition,for patients suffering from needle phobia,it can cause mental suffering,and even cause fainting,with serious consequences.The microsystem of transdermal drug delivery with microneedle-based and sonophesis proposed in this paper can avoid or eliminate these problems during the administration process.The stratum corneum of the skin limits the penetration of the drug solution into subcutaneous tissue through skin during transdermal administration.The microneedles technique can effectively penetrate the stratum corneum without causing obvious pain and trauma.The permeability and absorption of drug solution in subcutaneous tissue can be improved by ultrasound-assisted osmosis on the basis of microneedle transdermal administration.In addition,because most of the ultrasound drug-mediated devices are large and bulky,the miniaturization and miniaturization of the drug delivery system is an urgent problem to be solved,which is very important for the construction of wearable ultrasound treatment devices which are convenient and easy to carry.The microsystem of transdermal drug delivery with microneedle-based and sonophesis proposed in this paper is an integrated system composed of a hollow microneedles structure with a drug reservoir and a MEMS capacitive micro-ultrasound transducer.Among them,the capacitive micro-ultrasonic transducer is mainly used to convert electrical energy into ultrasonic energy to promote the penetration and absorption of the drug in the epidermis and dermis.Previous ultrasound-assisted osmotic enhancement methods mainly use the cavitation effect of low-frequency ultrasound to increase the permeability of the outermost stratum corneum of the skin in order to promote drug transdermal delivery.In this paper,the microneedle based on MEMS technology is used to penetrate the stratum corneum directly into the epidermis and dermis.Ultrasound is mainly used to promote the permeability and diffusion rate of drug solution in the epidermis and dermis,and then to promote the rapid absorption of drug solution by tissue.Based on the analysis of the mechanism of ultrasound-induced osmosis,a model of the subcutaneous osmosis process of drug solution after microneedle administration was established.The affecting factors in the process of osmosis are analyzed,and the effect is analyzed.At present,the equipment of ultrasonic source is huge and bulky,which hinders the development of this technology.In this paper,a micro-ultrasonic transducer is proposed as a launching source.The capacitive micro-ultrasonic transducer for transmitting ultrasonic source is analyzed.Through static analysis,modal analysis and collapse voltage analysis,the parameters of the model are selected,and the analysis results are compared with the macro-theoretical model to verify the rationality of the model parameters selection.Finally,the fabrication process of transdermal drug delivery microsystems is arranged and the key technologies are analyzed and discussed.