refrigerated overnight during which time trapped air escapes prior to the assay the meal is removed from the refrigerator and allowed to warm to room temperature mature 170 to 204 g male sprague dawley rats are deprived of food for 24 hours with water ad libitum on the morning of the study each animal is weighed and randomly assigned to treatment groups consisting of ten animals per group each rat receives either vehicle test compound or the reference standard metoclopramide by intraperitoneal injection at 0 5 hours post injection 3 0 ml of test meal is orally administered to each rat with a 5 0 ml disposable syringe five test meal samples are weighed on an analytical balance and these weights are averaged to find a mean test meal weight at 1 5 hours post injection each rat is sacrificed by carbon dioxide asphyxiation and the stomach is removed by opening the abdomen and carefully clamping and cutting the esophagus just below the pyloric sphincter taking care not to lose any of the its contents each stomach is placed on a small pre weighed and correspondingly labeled 7 ml weigh boat and immediately weighed on an analytical balance each stomach is then cut open along the lesser curvature rinsed with tap water gently blotted dry to remove excess moisture and weighed the amount of test meal remaining in the stomach is represented by the difference between the weight of the full stomach and the weight of the stomach empty the difference between the.