高载多肽纳米复合载体的超快速联动制备

Encapsulation of water-soluble peptides into nanoparticles remains a tremendous challenge from both theory and application perspectives. In this project, we propose the super-fast and sequential desolvent-precipitation flow technique based on microfluidics. This proposed technique can fulfill nanoprecipitation of therapeutic peptides in polymer carrier to achieve ultra-high drug loading. The most prominent feature of such strategy is the superfast formation of nanocomposites with high mass fraction of peptides. Specifically, the pure peptides precipitated in the first step form nanoparticles. In extremely short time intervals, these peptide nanoparticles are supposed to be directly encapsulated in polymer matrix by microfluidic nanoprecipiation. The precipitation of peptide themselves in anti-solvent instantaneously occur, which exponentialy confine the contact of drug with anti-solvent. As a result, the native secondary structure and biological activity of peptides can be conserved in a large extent. In addition, no intermediate purification is needed, and the freshly formed peptide nanoparticles can be directly encapsulated, which can significantly enhance the production efficiency. The size of nanocomposites and the shell thickness are tunable by adjust the microfluidic operation parameters. Under optimal condition, nanocomposites are ultrahigh throughput produced. Thereafter, the drug release profile of nanocomposites and in vivo potency and pharmacokinetics are also performed. To pave the way for applicability and generality of this approach in core/shell structure nanocomposites preparation, we conduct computational fluid dynamics simulation to identify the key factors which are determinant to the peptide nanoprecipitation and encapsulation.

制备高效包载水溶性多肽类药物的纳米递送系统，在理论和实践上都面临巨大挑战。本项目提出一种基于微流控的超快速脱溶剂和包衣联动技术，期望实现多肽类药物的超高载药。该技术的最大特点在于高载多肽纳米复合载体的超快速连续制备。首先，多肽类药物瞬间析出形成粒径均一纳米粒后，于极短时间内进行微流控包衣，大幅降低多肽类药物与有机溶剂的接触时间，最大限度保持多肽类药物的活性和结构。其次，联动生产避免多肽类药物纳米粒的纯化和浓缩，直接高效包衣多肽纳米粒，大幅提高包载多肽纳米复合载体的制备效率。本项目拟通过微流控参数调节，优化纳米复合载体的粒径、聚合物外壳的厚度等理化特性，评价相关处方的药物体外释放速率、及体内药效和药代动力学性质；并结合计算流体力学模拟，揭示影响纳米粒聚合物包裹过程中的决定因素，阐明纳米复合载体的形成机理和规律，从理论上指导包载水溶性多肽纳米载体的制备。

多肽分子与聚合物材料间较低的相容性限制了聚合物微球、纳米粒、胶束等微粒对该类药物的包载效率。此外，传统方法所制备微粒的重现性较差，不同批次间微粒的粒径、载药量、药物释放等存在较大差异，导致工业生产困难。本研究提出并验证“表面伪装”假说，用于指导多肽类药物的高效包载。该假说将多肽药物分子转化为胶体颗粒，利用聚合物的吸附实现胶体颗粒表面的亲油性伪装，改善多肽类药物与聚合物基质间的相容性，使得胶体颗粒稳定分散在油相中，抑制药物从油相到水相的扩散，实现多肽蛋白类药物的高效包载。为避免批次间差异，本项目采用快速沉淀和乳化联动的连续流技术，分别用于制备多肽胶体颗粒和包裹药物胶体颗粒的乳滴，并将其迅速固化形成微粒。连续化制备可以减少多肽类药物胶体颗粒的纯化和浓缩步骤，提高制备效率，减少制备过程的人为操作，为基于连续流的微粒制剂工业化生产提供指导。