Terahertz-based analysis of immediate-release tablet hydration and disintegration: Effects of croscarmellose sodium and magnesium stearate

This study investigated the influence of croscarmellose sodium (CCS) and magnesium stearate (MgSt) on tablet hardness, hydration time, and disintegration time to understand their roles and interactions at different stages of the disintegration process using terahertz pulsed imaging technique. Six powder blends were formulated by combining three CCS concentrations (3%, 4%, and 5%w/w) and two MgSt concentrations (0.5% and 1%w/w) and were direct-compressed. A high-power terahertz time-domain spectrometer with an open-immersion cell was used to track the advancing liquid front in the tablet matrix during disintegration. The obtained liquid transport profiles were analysed alongside tensile strength and disintegration time to explore how CCS and MgSt affect the tablet matrix. The results highlighted (1) the critical role of the liquid penetration process in understanding the disintegration mechanisms, and (2) the contradictory effects of CCS and MgSt, as both excipients exhibited factors that accelerated and retarded disintegration at different stages. These findings lay the groundwork for optimising immediate-release tablet formulations and developing predictive disintegration models.