Abstract: Inhibitory Effect of 5-Fluorouracil/Chitosan Drug-loaded Microspheres on the Growth of Peri-toneally Seeded Gastric Cancer Cells in Nude MiceXiaoping XIE1, Binhong YI1, Jinzhong DUANMU1, Zhengrong LI1,Wenxue CHEN2, Zhigang JIE1Correspondence to: Xiaoping XIE, E-mail: xply64@126.com1The Second Department of General Surgery, The First Affiliated Hospital of Nanchang University, Nanchang 330006, China2Jiangsu Provincial Cancer Institute, Nanchang 330029, ChinaThis work was supported by the Research Fund from Department of Education of Jiangxi Province [No. 2007(77)]Abstract Objective: To observe the inhibitory effect of 5-fluorouracil-Chitosan microspheres on the growth of gastric cancercells peritoneally seeded in nude mice. Methods: The 5-fluorouracil-loaded chitosan release microspheres were prepared using theemulsion cross-link method. The basic characteristics and the release properties of the microspheres were determined in vitro. Thir-ty-two nude mice with peritoneally seeded gastric cancer cells were randomly divided into 4 groups: the mice in group A were intraperi-toneally implanted with 5-fluorouracil chitosan microspheres, group B were implanted with blank chitosan microspheres, group C wastreated with 5-fluorouracil, and group D received saline solution management. Results: The particle size and the drug encapsulation ef-ficiency of the 5-fluorouracil-loaded chitosan microspheres were 185.5 ± 15.0 nm and 49.3% ± 2.1%, respectively. The microspheresshowed a slower drug release profile in vitro. As for intraperitoneal chemotherapy, compared with the other 3 groups, 5-fluorouracil chi-tosan microspheres significantly decreased the abdominal circumference, increased the body weight of the treated nude mice ( P >0.05 ), and reduced the number of peritoneal cancerous foci ( P < 0.05 ). Treatment with 5-fluorouracil chitosan microspheres also in-creased the apoptosis rate of the gastric cancer cells in ascites ( P < 0.01 ) and improved the survival rate ( P < 0.05 ). Furthermore, thetoxicity of the treatment was rare ( P < 0.05 ). Conclusion: 5-fluorouracil chitosan microspheres for peritoneal chemotherapy can effec-tively inhibit the growth of intraperitoneal gastric cancer cells in nude mice ,with low rate of toxicity.Keywords 5-Fluorouracil; Chitosan microspheres; Intraperitoneal chemotherapy; Gastric cancer