Theoretical investigations into the influence of the position of a breaking line on the tensile failure of flat, round, bevel-edged tablets using finite element methodology (FEM) and its practical relevance for industrial tablet strength testing.
Theoretical investigations into the influence of the position of a breaking line on the tensile failure of flat, round, bevel-edged tablets using finite element methodology (FEM) and its practical relevance for industrial tablet strength testing.
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使用有限元方法 (FEM) 理论研究断裂线位置对扁平、圆形、斜边片剂拉伸破坏的影响及其与工业片剂强度测试的实际相关性。
DOI：
10.1016/j.ijpharm.2014.10.028
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发表时间：
2014
影响因子：
5.8
通讯作者：
P. Fromme
中科院分区：
文献类型：
--
作者：
F. Podczeck;J. Newton;P. Fromme
扁平、圆形片剂可能有断裂（“刻痕”）线。药典片剂断裂负荷试验在其设计中是径向的，并且工业上使用的断裂负荷试验机通常具有自动片剂进料系统，其将片剂定位在机器的加载压板之间，其中断裂线与所施加的负荷随机取向。这项工作的目的是确定断裂线的位置的影响，在径向压缩试验中使用有限元方法（FEM）和比较的理论结果与实际结果，使用商业生产的斜边，刻痕片。研究了断裂线测试位置与加载平面成0°、22.5°、45°、67.5°和90°角。对于完全弹性和弹塑性片剂获得的FEM结果相当相似，但它们突出了取决于断裂线位置的应力分布的巨大差异。对于在45°或更大角度下测试的片剂，预测失效时的应力值相似，而在较低的测试角度下，预测的断裂载荷最多大三倍。应力分布表明，并非所有断裂线角度都会导致完全拉伸失效。然而，实际结果并没有证实预测断裂载荷的差异，但它们证实了片剂断裂方式的差异。结果表明，不建议将刻痕片剂上获得的断裂载荷转换为片剂抗张强度值，不同片剂或批次之间的比较应仔细考虑断裂线相对于载荷平面的方向，因为失效机制似乎各不相同。
Flat, round tablets may have a breaking (“score”) line. Pharmacopoeial tablet breaking load tests are diametral in their design, and industrially used breaking load testers often have automatic tablet feeding systems, which position the tablets between the loading platens of the machine with the breaking lines in random orientation to the applied load. The aim of this work was to ascertain the influence of the position of the breaking line in a diametral compression test using finite element methodology (FEM) and to compare the theoretical results with practical findings using commercially produced bevel-edged, scored tablets. Breaking line test positions at an angle of 0°, 22.5°, 45°, 67.5° and 90° relative to the loading plane were studied. FEM results obtained for fully elastic and elasto-plastic tablets were fairly similar, but they highlighted large differences in stress distributions depending on the position of the breaking line. The stress values at failure were predicted to be similar for tablets tested at an angle of 45° or above, whereas at lower test angles the predicted breaking loads were up to three times larger. The stress distributions suggested that not all breaking line angles would result in clean tensile failure. Practical results, however, did not confirm the differences in the predicted breaking loads, but they confirmed differences in the way tablets broke. The results suggest that it is not advisable to convert breaking loads obtained on scored tablets into tablet tensile strength values, and comparisons between different tablets or batches should carefully consider the orientation of the breaking line with respect to the loading plane, as the failure mechanisms appear to vary.