Investigation of water vapour sorption mechanism of starch-based pharmaceutical excipients

Saeid Rajabnezhad, Taravat Ghafourian, Ali Rajabi-Siahboomi, Shahrzad Missaghi, Majid Naderi, Jonathan P. Salvage, Ali Nokhodchi

Research output: Contribution to journalArticlepeer-review


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, which is 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.

Original languageEnglish
Article number116208
JournalCarbohydrate Polymers
Publication statusPublished - 23 Mar 2020


  • BET theory
  • DVS
  • Pregelatinisation
  • Starch 1500
  • Starch powder
  • Water sorption-desorption
  • SEM
  • Scanning electron microscopy

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