Investigations into the mechanical strength anisotropy of Sorbitol Instant compacts made by uniaxial compression
Investigations into the mechanical strength anisotropy of Sorbitol Instant compacts made by uniaxial compression
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单轴压缩山梨醇速溶压块机械强度各向异性的研究
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
F. Podczeck
中科院分区：
文献类型：
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作者：
F. Podczeck
摘要制药工业生产的粉末压坯通常是通过对粉末或颗粒进行单轴压缩来生产的。这一过程产生了机械强度各向异性的压坯，但这一假说在过去很少受到关注。在这项工作中，山梨醇颗粒使用两种截然不同的颗粒大小、两种压实速度和一系列不同的片剂孔隙率来生产压片。通过径向和双向压缩以及弯曲弯曲来评估紧凑的拉伸强度。用断裂力学，即I型和II型加载下的临界应力强度因子，以及断裂包络的构造，研究了破坏机制和强度各向异性。采用威布尔分析和方差分析对强度结果进行统计分析。颗粒大小和压实速度是影响拉伸强度的主要因素。然而，所发现的影响的大小在不同的测试配置之间是不同的。对不同试验得到的威布尔模数进行进一步处理，证实了单轴压缩粉末压坯的各向异性。他们还表明，通常用来获得抗拉强度值的径向压缩试验是评估颗粒特性对机械强度影响的最不敏感的方法。双轴试验发现，由于山梨醇颗粒特性的微小变化，能够检测到裂纹和缺陷结构的微小变化。
Abstract Powder compacts manufactured by the pharmaceutical industry are usually produced by uniaxial compression of powders or granules. This process results in compacts that are anisotropic in their mechanical strength, but this hypothesis has received little attention in the past. In this work, compacts were produced from sorbitol granules using two distinctively different particle size fractions, two compaction speeds and a range of different tablet porosities. The compact tensile strength was assessed by diametral and biaxial compression and by flexural bending. Fracture mechanics, i. e. the critical stress intensity factors in mode I and II loading, and the construction of the fracture envelope were used to investigate failure mechanisms and strength anisotropy. The strength results were also analyzed statistically employing Weibull analysis and analysis of variance. Granule size and compaction speed were identified as major influence factors on tensile strength. The magnitude of the effects found, however, varied between the individual test configurations. Further processing of the Weibull moduli obtained from the different tests confirmed the anisotropy of powder compacts made by uniaxial compression. They also showed that the commonly used diametral compression test to obtain tensile strength values is the least sensitive measure to assess the influence of particle properties on mechanical strength. Biaxial testing was found to be able to detect small changes in crack and flaw structure as a result of small changes in the particle characteristics of sorbitol.