2.6. Wash‐Off Test (In Vitro)The Ranga Rao and Buri [23] method was used to determine the adhesiveness of the nanoparticles. Rats were anesthetized using isoflurane/O2. The mucosal layer of the stomach (∼5 cm in length, 1 m in width) was neatly cut and washed in normal saline. Then, 100 mg of the drug was carefully placed on the mucosal surface and allowed to interact for up 30 minutes [24]. The mucus layer was placed in a desiccator for up to 15 minutes; the humidity was set at 90%. The mucosal layer was washed in saline at a flow rate of 5 mL/minute. The concentration of the drug was read in a spectrophotometer.