Abstract: Objective To evaluate the validity and rationality of loperamide as the modeling agent to asses the effect of relaxing bowel using diphenoxylate as a reference. Methods The appropriate dosages of diphenoxylate and loperamide as modeling agents were screened. The validation tests were performed with the same health food which had been sold as having the facilitating feces excretion function. The small intestine movement experiment and the defecation experiment were carried out. Results (1) Screening tests: Within the screening doses, the ink propulsion rate of the two modeling drugs were less than the control group (P<0.05), so both of the small intestine peristalsis inhibition were established successfully. Within the screening doses, loperamide at the dose of 9 mg/kg and 10 mg/kg induced the constipation, none of diphenoxylate. (2) Validation tests: The animal models were succeeded with the same dosage of diphenoxylate and loperamide. The ink propulsion rates of the test substance were greater than their model control groups respectively (P<0.01). The first defecating time, the amount of feces and fecal weight within 6h of the test substance were significantly different with their model control groups (P<0.01). Loperamide and diphenoxylate have the same effect of functional food. Conclusion Loperamide can be used as amodeling drug for assessing the facilitating feces excretion function. in the appropriate dose.

Key words: Diphenoxylate, Loperamide, Animal model