Fichtner Frauke, Mahlin Denny, Welch Ken, Gaisford Simon, Alderborn Göran
Department of Pharmacy, Uppsala University, Uppsala, Sweden.
Pharm Res. 2008 Dec;25(12):2750-9. doi: 10.1007/s11095-008-9639-7. Epub 2008 Jun 12.
The influence of surface energy on the compactibility of lactose particles has been investigated.
Three powders were prepared by spray drying lactose solutions without or with low proportions of the surfactant polysorbate 80. Various powder and tablet characterisation procedures were applied. The surface energy of the powders was characterized by Inverse Gas Chromatography and the compressibility of the powders was described by the relationship between tablet porosity and compression pressure. The compactibility of the powders was analyzed by studying the evolution of tablet tensile strength with increasing compaction pressure and porosity.
All powders were amorphous and similar in particle size, shape, and surface area. The compressibility of the powders and the microstructure of the formed tablets were equal. However, the compactibility and dispersive surface energy was dependent of the composition of the powders.
The decrease in tablet strength correlated to the decrease in powder surface energy at constant tablet porosities. This supports the idea that tablet strength is controlled by formation of intermolecular forces over the areas of contact between the particles and that the strength of these bonding forces is controlled by surface energy which, in turn, can be altered by the presence of surfactants.
研究表面能对乳糖颗粒可压性的影响。
通过喷雾干燥乳糖溶液制备了三种粉末，一种不含表面活性剂聚山梨酯80，另两种含有低比例的该表面活性剂。采用了各种粉末和片剂表征方法。通过反相气相色谱法表征粉末的表面能，用片剂孔隙率与压缩压力之间的关系描述粉末的可压缩性。通过研究片剂抗张强度随压实压力和孔隙率增加的变化来分析粉末的可压性。
所有粉末均为无定形，粒径、形状和表面积相似。粉末的可压缩性和所形成片剂的微观结构相同。然而，粉末的可压性和分散表面能取决于粉末的组成。
在片剂孔隙率恒定的情况下，片剂强度的降低与粉末表面能的降低相关。这支持了以下观点：片剂强度受颗粒间接触区域分子间力形成的控制，而这些键合力的强度受表面能控制，表面能又可因表面活性剂的存在而改变。
