Study On The Transcutaneous Immunization System Of Dissolving Microneedle Arrays

Objective: To prepare a transcutaneous immunization(TCI)with dissolving microneedle arrays(DMNAs),where in the tips are loaded with ovalbumin(OVA).To determine the feasibility of transdermal drug delivery by various characterization techniques in vitro,and the efficacies for the transcutaneous delivery of antigen and the immune response induced in vivo.The safety of transdermal drug delivery was investigated by skin irritation test.It is expected to provide scientific guidance and theoretical basis for the study of the TCI of DMNAs and the development of vaccines.Methods: 1.Precision machinery manufacturing technology and computer aid design(CAD)were employed to design and fabricate the mold of DMNAs.2.Two-step molding process was used to prepare DMNAs.And to establish in vitro evaluation methods for the feasibility of DMNAs in transdermal drug delivery by scanning electron microscopy,excised skin insertion test.3.Eastablish a method for determining the content of OVA in the DMNAs,and determine the optimal prescription applicable to this study through the mechanical properties and drug loading of the DMNAs.Then,the prepared DMNAs was characterized by surface regularity,drug loading,and mechanical properities.4.The stability of the OVA in DMNAs was investigated by SDS-PAGE.5.OVA was used as a model antigen,by detecting the serum IgG levels in SD rats,the efficacy and superiority of transcutaneous immunization of DMNAs was evaluated.6.To establish a preliminary method for the safety evaluation of DMNAs through the skin irritation test,hemolysis test,material toxicity test.Results: 1.A brass master mold of 100 conical microneedles was made using computer aided design(CAD).Female molds were made from polydimethylsiloxane(PDMS)by exactly inversely replicating the master structures.2.The shape of the OVA-DMNAs that prepared by two-step molding process was found to be complete and regular through microscope.The OVA-DMNAs could be confirmed that it has a certain degree of mechanical strength through skin insertion test,and it can be concluded that the TCI in this study is feasible.3.The optimal prescription for this study was determined by both the mechanical properties and the drug loading content.An aqueous solution of dextran(Dex)at a concentration of 300 mg/mL was selected as the needle material,and an aqueous solution of polyvinyl pyrrolidone(PVP K90)at a concentration of 333 mg/mL was selected as the base material.Ovalbumin(OVA)was selected as the model antigen.4.The results of SDS-PAGE showed that the DMNAs aqueous solution band was the same as the OVA aqueous solution band,and no other bands appeared.And the blank-DMNAs aqueous solution does not have this characteristic band.5.In vivo pharmacodynamics experiments in rats showed that the transdermal delivery of DMNAs could elicit an immune response.Compared with the subcutaneous injection,a half dose of the DMNAs can lead to a considerable level of antibody,while the same dose of the DMNAs can lead to a higher level of antibody.6.After skin irritation test,hemolysis test and materials toxicity test of DMNAs,it was found that the DMNAs is safe to use and has no skin irritation.Conclusions: The DMNAs prepared in this project has good mechanical properties and advantages of transcutaneous immunization,and it is safe to use,has no skin irritation,and can provide scientific guidance and theoretical basis for the study of transcutaneous immunization of DMNAs and the development of vaccines.