Objective: The need of this study was to develop tableted microspheres that can be targeted to colon because metronidazole (MNZ) has good solubilityat pH 1.2; hence, coating of the drug with the suitable pH dependent is done to prevent its release in the gastric region.Methods: Colon targeted tablets of MNZ were prepared with enteric coated microspheres using pH dependent polymers such as cellulose acetatephthalate, hydroxypropyl methylcellulose phthalate, and Eudragit S 100 by solvent evaporation method. All the formulations were prepared bychanging drug-polymer ratio from 1:1 to 1:5 and the interactions of the drug with polymers were studied by Fourier transform infrared and thermalanalysis.Results: Formulations F5, F8, and F were found to best optimized in percentage yield, drug entrapment efficiency, mean particle size and in vitrodrug release. The result obtained were found in the desired ranges where % yield ranging from 52.56% to 98.253%, drug entrapment efficiency from42.17% to 99.017%, and mean particle size from 36.774 to 229.961 µm. Then, tablet of optimized formulations was prepared by direct compressionmethod and in vitro drug release was performed. All the parameters of tablets were found acceptable as per IP guideline. Around 4-10% drug releasewas in 0.1 N HCl after 2 hrs, 50% release at pH 7.4 phosphate buffer within 5 hrs, maximum retardation was found in the formulation of Eudragit S100. Scanning electron microscopy permitted a surface topographical analysis.14Conclusion: The MNZ tableted microspheres showed their release at pH 7.4 thus this experimental work can be used to improve absorption of drugin colon for successful treatment of the disease.Keywords: Metronidazole, Tableted microspheres, Solvent evaporation method, Direct compression method
