A Novel Method to Quantitatively Evaluate Slipperiness and Frictional Forces of Solid Oral Dosage Forms and to Correlate These Parameters with Ease of Swallowing

Patient adherence to oral solid dosage forms depends majorly on the ease of swallowing of these formulations. Conventional methods of evaluating this property is not reflective of the actual scenario as endogenous factors, such as adhesion to the mucus membranes from the oral cavity to the stomach, are not considered. Therefore, we developed a novel method based on the use of a creep meter to measure frictional resistance between various dosage forms and artificial skin as physical properties related to the ease of swallowing formulations. First, the sample was subjected to load (0.5 N for 5 s) from the top, corresponding to tongue press. Next, the sample was moved in the horizontal direction at a speed of 1 mm/s while keeping the vertical load, and the frictional force generated between the artificial skin of the plunger and the sample surface was measured for 15 s. The frictional force was measured under dry conditions and after the sample was immersed in water. According to the novel in vitro evaluation method of slipperiness developed in this study, it is possible to design a slippery and easy-toswallow formulation that could contribute to improved patient adherence.