Development of an Objective Evaluation Method for Texture Contributing to Ease of Swallowing in Orally Disintegrating Tablets

Orally disintegrating tablets (ODTs) are used widely for patients with swallowing difficulties, particularly elderly individuals and children. Although previous studies have focused on taste masking and disintegration time, the impact of texture on ease of swallowing has not been well quantified. This study aimed to examine an objective evaluation method for texture attributes contributing to swallowability by integrating sensory evaluation and instrument analysis. Ten placebo ODT formulations with different excipient compositions were prepared. Sensory evaluation was conducted using a seven-point semantic differential scale assessing smoothness, ease of disintegration (crumbling) , and overall ease of swallowing. Instrument analyses included shear rheological measurements to determine flowability (inverse viscosity) and multi-bite compression testing to quantify compressive disintegration energy. Flowability showed strong positive correlations with sensory smoothness, while compressive disintegration energy demonstrated strong negative correlations with perceived ease of disintegration and ease of swallowing. Multiple regression analysis using instrument parameters as explanatory variables showed high explanatory performance for ease of swallowing in the present sample set (adjusted R2=0.876). These findings suggest that instrument measurements of rheological behavior and compression-induced disintegration characteristics may serve as supplementary objective indicators of swallowability. The proposed framework provides a practical approach for designing patient-friendly ODT formulations, possibly contributing to improved medication adherence.