Background: Gut microbiota has a significant role in the pathogenesis of
diabetes. Colonic microflora modulation using an antibiotic might have an emerging
role to treat the metabolic disorders. The present study was aimed to optimize the
Moxifloxacin loaded chitosan microspheres (MCMs) by emulsion cross linking
method for colon targeted delivery to alter the microflora.
Methods: Preliminary optimization of MCMs was carried out using Placket-Burman
design (PBD) following by final optimization with Box-Behnken design (BBD). Optimized
MCMs were evaluated for yield, particle size, entrapment efficiency and in
vitro/ in vivo antimicrobial activities.
Results: FTIR spectroscopy of MCMs confirms the absence of chemical interactions during the formulation.
MCMs were found to be smooth, spherical with particle size around 20μm. An enteric coating of
MCMs prevented the drug release in the acidic environment of the stomach and ileum with complete
release at the colon. MCMs had followed the korsmeyer - peppas model of drug release, indicating the
drug release by non-fickian diffusion pattern. MCMs showed significant in vitro antimicrobial activity
against Lactobacillus casei and Escherichia coli. In vivo results of MCMs exhibited prolonged antimicrobial
effect of drug in the cecal content of rats. Significant protective activity observed in the ileum
and colon histology in rats treated with MCMs compared to the pure drug.
Conclusion: MCMs were formulated by emulsion cross linking method using QBD approach. An enteric
coating around the microspheres prevented the premature drug release at upper gastrointestinal tract,
while chitosan cross linking has provided the sustain release of the drug in the colonic region over the