van Veen B, van der Voort Maarschalk K, Bolhuis G K, Zuurman K, Frijlink H W
Department of Pharmaceutical Technology and Biopharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
Int J Pharm. 2000 Aug 10;203(1-2):71-9. doi: 10.1016/s0378-5173(00)00450-6.
The tensile strength of tablets compressed from binary mixtures is in general not linearly related to the strength of tablets prepared from single materials; in many cases it shows a decreased tensile strength relative to interpolation. The materials used in this study, sodium chloride and pregelatinised starch, are both plastically deforming materials, but have a different densification and relaxation behaviour. The yield pressure of the binary mixtures shows an almost linear relationship. As an effect of their lower yield pressure, starch particles yield earlier than sodium chloride particles. The following enclosure prevents some sodium chloride particles to yield or crack. The relaxation of the tablets is higher than the relaxation calculated by linear interpolation of the relaxation behaviour of the two pure materials. The difference between the measured porosity expansion and the data obtained by linear interpolation can be considered as a measure for the reduced interparticle bonding. SEM-photographs indicate that the reduced interparticle bonding is caused by the low adhesive forces. The measured decrease of the tensile strength of the tablets is also considered to be the result of reduced interparticle bonding. In this paper it is shown that there exists a similar relationship between the tensile strength reduction and the percentage of starch on the one hand and the extra porosity expansion and the starch percentage on the other hand.
由二元混合物压制而成的片剂的抗张强度通常与由单一材料制备的片剂的强度并非呈线性关系；在许多情况下，相对于内插法，其抗张强度会降低。本研究中使用的材料，氯化钠和预胶化淀粉，都是发生塑性变形的材料，但具有不同的致密化和松弛行为。二元混合物的屈服压力显示出几乎呈线性关系。由于其较低的屈服压力，淀粉颗粒比氯化钠颗粒更早屈服。随后的包裹层阻止了一些氯化钠颗粒屈服或开裂。片剂的松弛度高于通过对两种纯材料的松弛行为进行线性内插计算得到的松弛度。测量得到的孔隙率膨胀与通过线性内插法获得的数据之间的差异可被视为颗粒间结合力降低的一种度量。扫描电子显微镜照片表明，颗粒间结合力降低是由低粘附力引起的。片剂抗张强度的测量降低也被认为是颗粒间结合力降低的结果。本文表明，一方面抗张强度降低与淀粉百分比之间，另一方面额外孔隙率膨胀与淀粉百分比之间存在类似的关系。
