Gucluyildiz H, Banker G S, Peck G E
J Pharm Sci. 1977 Mar;66(3):407-14. doi: 10.1002/jps.2600660323.
Total porosity and pore-size distribution of aspirin tablets prepared from aspirin, starch USP, and precipitated colloidal silicon dioxide were determined using mercury porosimetry. The model represented a hydrolyzable drug substance in combination with simple excipients. The role of starch and silicon dioxide on the microstructure of the tablets was investigated, as was the chemical stability of various systems. In general, the porosity of tablets containing a constant quantity of starch increased linearly with silicon dioxide concentration. Examination of the pore-size distribution, however, revealed that a low concentrations silicon dioxide functioned primarily to reduce the size and volume of coarse pores representing the spaces between the agglomerates of starch and aspirin particles. This effect was optimum at 3%. A further increase in silicon dioxide concentration produced tablets with relatively larger pore sizes. Studies of changes in the porosity characteristics of tablets as influenced by water vapor over time showed distinct differences in this complex parameter. A unique trend in the change of the pore-size distribution was noted with tablets containing 3% silicon dioxide. These observations are discussed relative to the stability of aspirin tablets in which this concentration of silicon dioxide produced a maximum stabilizing effect.
使用压汞法测定了由阿司匹林、美国药典级淀粉和沉淀胶态二氧化硅制备的阿司匹林片剂的总孔隙率和孔径分布。该模型代表了一种可水解药物与简单辅料的组合。研究了淀粉和二氧化硅对片剂微观结构的作用，以及各种体系的化学稳定性。一般来说，含有恒定数量淀粉的片剂的孔隙率随二氧化硅浓度呈线性增加。然而，对孔径分布的研究表明，低浓度的二氧化硅主要起到减小代表淀粉和阿司匹林颗粒团聚体之间空隙的粗孔尺寸和体积的作用。这种效果在3%时最佳。二氧化硅浓度的进一步增加会使片剂的孔径相对变大。对水蒸气随时间影响片剂孔隙率特性变化的研究表明，在这个复杂参数上存在明显差异。含有3%二氧化硅的片剂在孔径分布变化方面呈现出独特的趋势。相对于阿司匹林片剂的稳定性讨论了这些观察结果，其中该浓度的二氧化硅产生了最大的稳定效果。
