Department of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Josai University.
Chem Pharm Bull (Tokyo). 2023;71(6):386-397. doi: 10.1248/cpb.c22-00539.
Various stresses and strains are generated on the surface and inside of pharmaceutical tablets when an external force is applied. In addition, stresses in various directions can remain on the surface and inside the tablets because they are generally prepared by compaction of pharmaceutical powders using dies and punches. As it is difficult to measure the stress and strain generation in the tablets experimentally, a numerical simulation was applied by employing a finite element method (FEM). An elastic model is often used to represent stress and strain generation after loading an external force to tablets, and the Drucker-Prager cap (DPC) model has been widely recognized for representing the remaining stress distributions during the compaction of powder to tablet form. Firstly, this article describes an FEM simulation of the stress generation on the surface of the scored tablets after loading the bending force from the back side of the tablets. Next, the FEM simulation was introduced to determine the effect of diametrical compression on the stress and strain generation in the tablets by comparing the results measured experimentally. Furthermore, the residual stresses remaining inside the tablets were simulated using FEM, in which powder compaction was represented as the DPC model. A clear difference was observed in the residual stress distributions between the flat and convex tablets. This indicates that FEM simulation is useful for achieving a science-based understanding of critical quality attributes in various types of tablets.
当外力施加于药物片剂的表面和内部时，会产生各种应力和应变。此外，由于片剂通常是通过使用模具和冲头将药物粉末压实制备而成，因此片剂的表面和内部会残留各向应力。由于难以通过实验测量片剂中的应力和应变产生情况，因此采用有限元法（FEM）进行了数值模拟。在对外力加载后的片剂进行弹性建模时，通常采用弹性模型来表示其产生的应力和应变，而 Drucker-Prager 帽（DPC）模型已被广泛认可，可用于表示粉末压制成片剂时的残余应力分布。本文首先描述了从片剂背面加载弯曲力后，在划刻片剂表面产生的应力的 FEM 模拟。接下来，通过比较实验测量结果，介绍了 FEM 模拟在确定直径压缩对片剂中应力和应变产生的影响方面的应用。此外，使用 FEM 模拟了片剂内部的残余应力，其中粉末压实采用 DPC 模型表示。在平坦片剂和凸面片剂之间观察到残余应力分布存在明显差异。这表明 FEM 模拟对于基于科学的理解各种类型片剂的关键质量属性非常有用。
