Starch-based excipients are commonly used in oral solid dosage forms. The effect of particle size and pregelatinisation level of starch-based excipients on their water absorption behaviour have been evaluated. The results showed that starch-based excipients have type ii isotherms, indicating that the principal mechanism of sorption is the formation of monolayer coverage and multilayer water molecules (10-80 RH%). It was found that the particle size of starch-based excipients did not have any influence on the rate of water sorption, whereas the level of pregelatinisation changed the kinetics of water sorption-desorption. Results showed that the higher the degree of pregelatinisation, the higher the rate of water absorption irrespective of particle size. SEM images showed that a partially gelatinised starch had a firm granular structure with small pores and channels on the surface while a fully gelatinised starch had more irregular and spongy like surface with a degree of fractured particles.

淀粉基赋形剂通常用于口服固体剂型。已经评估了淀粉基赋形剂的粒径和预糊化水平对其吸水行为的影响。结果表明，淀粉基赋形剂具有ii型等温线，表明吸附的主要机理是单层覆盖和多层水分子（10-80 RH％）的形成。发现淀粉基赋形剂的粒径对吸水率没有任何影响，而预糊化水平改变了吸水-解吸的动力学。结果表明，与颗粒大小无关，预糊化程度越高，吸水率越高。