Insufficient gastric mucosa drug concentration and short contact time were the 
main reason for the lack of eradication efficacy of Helicobacter pylori for 
peptic ulcer patients. Novel multi-core chitosan microspheres were prepared for 
stomach-specific delivery of hydrophilic antibiotics for the treatment of peptic 
ulcer. Chitosan microspheres with multiple Eudragit L100 cores were easily 
prepared by a new emulsification/coagulation encapsulating method. Swelling 
behaviors, surface amino groups and mucin absorption ability were investigated 
and the formulation that showed best mucoadhesive potential was adopted. The 
multi-core chitosan microspheres exhibited good mucoadhesiveness as well as 
controlled release manner for incorporated antibiotics in acidic environment. 
The release rate could be easily modulated with accumulative release ranging 
from 47.3 to 79.3% in 6 h. Accordingly, the multi-core chitosan microspheres 
could serve as a satisfactory vehicle for stomach-specific delivery of 
hydrophilic antibiotics.