College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, China.
College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, China.
Int J Pharm. 2021 Apr 15;599:120410. doi: 10.1016/j.ijpharm.2021.120410. Epub 2021 Feb 25.
The poor printability of most pharmaceutical polymers greatly restricts the application of the fused deposition modeling (FDM) technique in the field of personalized pharmaceutical preparations. General strategies to improve printability and provide practical guidelines for the optimization of formulations are lacking. Moreover, the mechanism associated with the smooth printing process of modified printing materials needs to be investigated. In this study, three different strategies were used to improve the FDM printability of typical brittle polymers with poor printability. The relationship among additives, material properties, and printability was explored. The finite element method was used to simulate the radial stress-strain behavior of the filament, while computational fluid dynamics was used to simulate the axial melt flow field in the printing head. It was found that the addition of an inert filler (i.e., talc), a drug with high melting points (i.e., diclofenac sodium), and a polymer with high strength (i.e., plasticized ethylcellulose) effectively improved the printability of plasticized Eudragit® EPO and Soluplus®. In addition, regulating the mechanical properties of filaments improved printability, and it was deduced that printable filaments should have neither very low stiffness nor very low flexibility. The suitable melt viscosity or shear-thinning property of the printing material facilitated smooth extrusion without filament breakage or nozzle blockage. The results of this study also showed that simulation could assist in understanding the stress-strain behavior of filaments and the flow field of melts during FDM printing.
大多数药物聚合物的印刷适性较差，极大地限制了熔融沉积成型（FDM）技术在个性化药物制剂领域的应用。缺乏提高印刷适性和为配方优化提供实用指导的一般策略。此外，还需要研究与改性打印材料顺利打印过程相关的机制。在这项研究中，使用了三种不同的策略来提高典型脆性聚合物的 FDM 印刷适性，这些聚合物的印刷适性较差。探讨了添加剂、材料性能和印刷适性之间的关系。使用有限元法模拟了细丝的径向应力-应变行为，同时使用计算流体动力学模拟了打印头中的轴向熔体流动场。结果表明，添加惰性填料（即滑石粉）、熔点高的药物（即双氯芬酸钠）和强度高的聚合物（即增塑乙基纤维素）可有效提高增塑 Eudragit® EPO 和 Soluplus®的印刷适性。此外，调节细丝的机械性能可提高印刷适性，可以推断出可印刷细丝既不应具有非常低的刚度，也不应具有非常低的柔韧性。打印材料的合适熔体粘度或剪切变稀特性有利于顺利挤出，而不会出现细丝断裂或喷嘴堵塞。这项研究的结果还表明，模拟可以帮助理解 FDM 打印过程中细丝的应力-应变行为和熔体的流动场。
