The present study was to develop a buoyant Hydrodynamically Balanced System (BHBS) for metronidazole (MN) using different formulations to show their effect on the floating time and in turn improving the sustained release pattern as a single unit floating capsule. The formulated blends were prepared using physical mixing of finely pulverized ingredients including the drug .The compatibility of different ingredients with the drug was studied using FTIR, DSC and XRPD techniques. The prepared BHBS capsules were also evaluated for drug content, weight uniformity and in vitro drug release. The drug release from different formulations relied on formulating ingredient, their concentrations and type of buoyant mechanism. Histopathological study. All formulations of MN sustained the drug release compared to capsule contains only pure MN.F7 depicted the best buoyant behavior. The histopathological study denoted a lack of metronidazole associated gastric mucosal cells injury in albino rats .The release data was best fit to first, diffusion model except F3 depicted first order kinetics.