University College London, Dept. Mechanical Engineering, London WC1E 7JE, UK.
Eur J Pharm Sci. 2010 Nov 20;41(3-4):483-8. doi: 10.1016/j.ejps.2010.08.002. Epub 2010 Aug 7.
The aim of this work was to determine the tensile strength of bilayered tablets made from different grades of microcrystalline cellulose. While these grades are chemically identical, they differ significantly in their particle size distribution and in their mechanical properties such as Young's modulus of elasticity. Tablets were produced in the shape of beams of similar dimensions using uniaxial compression, and solid beams made from one material only were compared with bilayered beams made from various combinations of powders. It was found that in the production of layered tablets it is important for the purpose of quality assurance and control that the upper and lower layer of the compact can be identified. Otherwise, tensile strength measurements will result in large variability depending on which layer faces upwards during the test. Both particle size and Young's modulus of elasticity influenced the overall strength of layered tablets. If the material forming the lower layer was more elastic, then the beam strength was reduced due to tension introduced into the system, acting especially at the layer interface and potentially causing partial or complete delamination. Larger differences in the particle size of the materials forming the tablet layers resulted in an overall reduced compact tensile strength.
本工作旨在测定由不同等级微晶纤维素制成的双层片剂的拉伸强度。虽然这些等级在化学上是相同的，但它们在粒径分布和杨氏弹性模量等机械性能方面有很大的差异。使用单向压缩将片剂制成具有相似尺寸的梁的形状，并将由一种材料制成的实心梁与由各种粉末组合制成的双层梁进行比较。结果发现，在生产分层片剂时，为了确保质量和控制的目的，重要的是可以识别压缩的上层和下层。否则，拉伸强度测量结果会因测试过程中哪个层朝上而产生很大的可变性。粒径和杨氏弹性模量都影响了分层片剂的整体强度。如果形成下层的材料更有弹性，那么由于系统中引入的张力，梁的强度会降低，这种张力主要作用在层界面上，并可能导致部分或完全分层。形成片剂层的材料的粒径差异越大，整体压实拉伸强度越低。
