基于纳米晶技术的纳米兽药的设计及体内作用规律研究

In recent years, food safety has become a more and more serious problem,which due to drug residues from animals edible product and antibiotic resistance. However, nano veterinary drugs with unique mechanism,could greatly ease and even solve these problems.By reference from nanocrystalline technology, this project aims to product new nanopartiele drugs, which mainly include enrofloxacin and valnemulin, by using nano precipitation and high-pressure homogenization method. Then, on this basis, antibacterial activity of nano drugs against pathogenic bacteria, sampling mycoplasma, intracellular bacteria, staphylococcus aureus , will be determined. Compared with common medicines, the change rules of the biological activity of nanometer drugs will be analysised. The correlations of nano drug sizes, stabilizer and antimicrobial activity are evaluated to provide the theory basis for the further design of stabilized nano drug of high quality. Later, pharmacodynamics and pharmacokinetics study will be carried out. With detecting the parameters of pharmacodynamics and pharmacokinetics and analysing the characteristics of pharmacokinetic,the pharmacological mechanism and depletion regular patter of nano veternary drugs will be explained. And a PK-PD model will be determinated, which could provide basis for the study of therapeutic effects of nano veternary drugs and formulation of clinical dosing regimen. In brief, if this subject put into effect, it can not only propose a new idea for developing the new veterinary antimicrobial drugs, but also provide the scientific basis for the evaluation of nanometer drugs.

动物源性食品药物残留引起的食品安全和抗生素耐药性问题日趋严重，而具有独特作用机制的纳米兽药能大大缓解甚至解决这些问题。本项目借鉴纳米晶（体）技术，以恩诺沙星、沃尼妙林为代表药，通过纳米沉淀-高压均质法制备纳米级药物；在对纳米药物进行结构表征的基础上，测试纳米药物对支原体、细胞内劳森菌、金葡萄球菌的体外抗菌活性，与普通药物对比，分析纳米药物生物活性的变化规律,评价纳米药物的尺寸、稳定剂组成等与抗菌活性的相关性,为进一步设计高质量的纳米兽药提供理论基础；开展药效学及药代动力学研究，建立PK-PD模型, 测定纳米药物的药效药动学参数，分析药动学特性，据此阐述纳米药物在动物体内的作用基础及消长规律。本项目实施为新型兽用纳米药物的创制提出新思路，也为纳米兽药体内作用规律研究提供新方法与理论基础。

纳米药物具有比表面积大、表面反应活性高、活性中心多、药动学特征好等特性，在保证药效的前提下，可显著减少用药量、降低细菌耐药的发生，有效缓解甚至解决动物源性食品药物残留引起的食品安全和抗生素耐药性问题。本课题对恩诺沙星、沃尼妙林、头孢洛宁及头孢噻呋四种动物专用抗菌药的纳米化技术进行了系统研究，利用混合沉淀-高压均质联用法成功制备出恩诺沙星纳米混悬注射剂、沃尼妙林纳米混悬液、头孢洛宁纳米冻干粉；通过药效、药动学研究，揭示了纳米药物的体内外作用规律。通过评价药物纳米晶尺寸与稳定剂的相关性，筛选出优选的稳定剂组方，解决了药物纳米晶的物理稳定性问题，3个受试药物在试验期内的粒径均稳定在800nm以内；开展了恩诺沙星纳米混悬剂、沃尼妙林纳米混悬液、头孢洛宁纳米冻干粉的药效学研究，研究发现抗菌药物纳米化后其体外抗菌活性优于或相当于原料药，体内药效优于普通制剂；药动学研究表明，与普通制剂相比，恩诺沙星纳米混悬注射剂、头孢洛宁纳米冻干粉在猪/兔体内消除缓慢、体内存留时间更长，其中恩诺沙星混悬注射剂tmax、t1/2ke及MRT显著延长，沃尼妙林纳米混悬液t1/2ke、MRT显著延长；PK-PD研究表明，恩诺沙星纳米混悬剂对大肠杆菌的抗菌类型为浓度依赖型,PK-PD参数为Cmax/MIC、AUC/MIC，模型方程为E= 2.8-7.83*C2.4 /(109.922.4 +C2.4)，预防用药为20mg/kg体重给药，治疗用药为45mg/kg体重给药，65mg/kg体重给药可根除细菌、避免耐药菌的产生。本项目的成功实施不仅为新型兽用抗菌药物的创制提出了新思路，也为纳米兽药的研制、注册及使用提供科学依据，具有重要的理论意义。

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