The Study On The Construction Of Harmine And Its Drug Delivery Via Nasal

The aging of population has become increasingly serious,and the health problem of the elderly has attracted more and more attention.Because of the aging population,Alzheimer’s disease（AD）has become amajor public problem and an important killer of human health.However,there is a lack of effective treatment drugs and methods.HAR can significantly inhibit the activity of monoamine oxidase and acetylcholinesterase,and has a good application and develo pment prospect in the treatment of AD.However,HAR is insoluble in water and has poor oral bioavailability.It is easily destroyed by acid,and the blood concentration fluctuates greatly.Furthermore,when its concentration is too high,it has certain toxicity to the nervous system and can cause hallucination,tremor and paroxysmal convulsion,which greatly limits its clinical application and efficacy.Therefore,to finda new drug delivery system for HAR has becomea problem to be solved.Insoluble drugs have problems of poor solubility and low bioavailability,and nanocrystalline technology provides a new way to improve this problem.And the in situ gel can prolong the drug retention time in the nasal cavity,reduce cilia clearance rate of the drug,reduce drug loss and pharyngeal irritation.Therefore,the combination of nanocrystal technology with in situ nasal gel can improve the bioavailability of HAR,prolong the action time of the drug,and reduce the toxicity of the drug.So,the main contents of this thesis are as follows:（1）Preparation of Harmine Nanocrystal composite particles（HAR-NCCP）Harmine Nanocrystal Suspension（HAR-NCS）was prepared by high-pressure homogenization method.From the stabilizer investigation results,it is clear that the particle size(D₅₀)of HAR-NCS prepared by different surfactants were all around 180 nm and the Zeta potential was all between-20 m V and 40 mV,indicating that the HAR-NCS with different stabilizers had good stability.The results showed that the particle size of HAR-NCS stabilized by P188 increased significantly,while the particle size of HAR-NCS stabilized by TW-80 and TP GS changed little.However,TPGS can increase the solubility of insoluble drugs,thus improving the absorption of drugs in the body.Therefore,TPGS is fina lly chosen as the stabilizer of NCS.Moreover,HAR-NCS was solidified by spray drying technology.The redispersibility and yield were taken as the maine valuation indexes to investigate the dosage of different protectant and protective agent.Through the investigation of the types of protective additives,it can be seen that the RDI was smaller and the yield was higher,when maltodextrin,t rehalose,lactose and mannitol were used as protective agent of HAR-NCCP.Therefore,maltodextrin,trehalose,lactose and mannitol were selected as protecti ve agent of HAR-NCCP.In addition,through the investigation of the amount o f protective agent,it can be seen that with the increase of the amount of prot ective agent,the redispersity and yield of HAR-NCCP both show an increasing trend.However,when the dosage of protective agent increased to 100%,the r edispersibility and yield of HAR-NCCP did not increase significantly,and consi dering the drug loading,100%was selected as the dosage of protective agent.（2）Characterization and evaluation of HAR-NCCPSEM,TEM,TG and IR were used to evaluate the characterization of HAR-NCCP.According to SEM results,the morphology of HAR-NCCP with 100%maltodextrin,mannitol and lactose as protectants was spherical or quasi spherical,and the middle was concave.However,HAR-NCCP with 100%trehalose as the protective agent had a serious aggregation and adhesion.TEM results showed that the particle size of HAR-NCS was nanometer and its shape was similar to spherical.From IR results,it can be concluded that there is no che mical reaction between HAR and stabilizer and protectant.It was speculated th at the intermolecular forces were mainly hydrogen bond and van der Waals for ce.DSC and XRD results showed that the crystal structure of HAR has not changed.The results of oil-water partition coefficient showed that the water solu bility of the HAR was better at p H 4,and the fat solubility was better at p H7.4.The results of in vitro release showed that TPGS could increase the dissol ution rate of HAR,and the preparation of HAR-NCCP could significantly incre ase the dissolution rate of HAR.（3）Preparation and evaluation of HAR-NCCP-DGGHAR-NCCP-DGG was evaluated by critical ion concentration,holding wat er capacity,expansion coefficient,pH value,rheology research,texture analysis and in vitro release.The results of critical ion concentration showed that the concentration of DGG solution should be between 0.3%and 0.6%.The results of holding water capacity showed that when the DGG concentration was more than 0.4%,there was no significant difference in water retention ability,and the water retention ability was more than 70%,with good water retention ability.The results of expansion coefficient showed that the expansion coefficient of DGG solution with different concentrations was less than 5%when mixed with ANF.And the pH value of 0.4%-1%HAR-NCCP-DGG met the requirements of nasal preparations.The Zeta potential results showed that the absolute value of Zeta potential of HAR-NCCP-DGG at different concentrations was above40,so the stability of HAR-NCCP-DGG with different concentrations was good.The rheological evaluation showed that the DGG solution added with ANF acted like a solid and could forma gel,and the viscosity decreased with the inc rease of shear rate.Therefore,it was judged to be a non-newtonian pseudoplas tic fluid,which had little effect on the secretion of nasal fluid.The results of texture analysis showed that with the increase of the concentration of DGG sol ution and when 0.5%DGG solution was mixed with ANF,its hardness,consiste ncy,viscosity index and other parameters showed an increasing trend.The final gel formulation was 0.5%Deacetylated gellan gum（DGG）and 1%1,2 propyl ene glycol（1,2-PG）.The results of in vitro release showed that HAR-NCCP-DG G was mainly dominated by the matrix diffusion.（4）The in vivo pharmacokinetic research of HAR-NCCP-DGG in ratsThe pharmacokinetics of HAR-NCCP-DGG was evaluated by intranasal ad ministration,and compared with that of rats after tail vein injection and intraga stric administration of equal dose HAR-NC.The results showed that the MRT of brain after nasal administration of HAR-NCCP-DGG was significantly higher than that of intravenous administration;Compared with oral administration,A UC_（0-∞）of HAR in brain was significantly increased after nasal administration.The absolute bioavailability of the brain after nasal administration of HAR-NC CP-DGG was 49.86%,however,25 times that of the oral administration of HA R-NC.In addition,compared with intravenous administration,the MRT of HA R in the brain increased nearly 5 times after nasal administration.This could b e attributed to the combination of nanocrystals and in situ gel,which can signi ficantly improve the dissolution of HAR in vitro,prolong the retention time of HAR in nasal cavity and promote absorption.On the other hand,nasal admin istration can avoid the p H environment and enzyme degradation in the gastroin testinal tract and liver first pass effect,so that its relative bioavailability is im proved.（5）In vivo pharmacodynamics of HAR-NCCP-DGGThe acute memory impairment model of mice was induced by intraperitoneal injection of scopolamine,and the effect of nasal administration of HAR on the learning and memory function was investigated.The results of platform test showed that the latency of mice in the middle dose group of nasal administ ration and the positive drug group was significantly increased.The results of nissl staining showed that HAR group had certain protective effect on neurons.The results of AchE and ACh content showed that the HAR group could inhib it Ach E activity.At the same dose,the effect of nasal administration group on Ach E inhibition was better than that of oral administration group.Besides,the content of ACh in hippocampus and serum was increased in the HAR group,which may be related to the inhibitory effect of Ach E.Therefore,HAR has a certain therapeutic effect on scopolamine induced memory impairment in mice,and the effect of nasal administration is better than that of oral administration.It may be that nanocrystal technology improved the dissolution rate of HAR,and in situ gel prolonged the time of HAR in vivo;In addition,the bioavailab ility of HAR-NCCP in nasal cavity was higher than that in oral administration.So,this provides a reference for the application and in-depth study of nasal HAR in AD.