Evaluation of physicochemical characteristics of metronidazole floating beads based on calcium silicate and gas forming agents

Abstract

In recent years scientific and technological advancements have been made in the research and development of controlled release oral drug delivery systems by overcoming physiological adversities, such as short gastric residence times and unpredictable gastric emptying times. Floating dosage forms that are designed to be retained in the stomach have been developed as a drug delivery system to overcome this physiological problem. Metronidazole is a nitroimidazolin antibiotic that is used for treatment of Helicobacter Pylori in combination with other drugs. In the present investigation metronidazole loaded floating alginate beads were prepared for local eradication of H. Pylori.

Materials and Methods: Gelation method was used for preparation of conventional sodium alginate beads consisting calcium silicate as porous carrier or NaHCO3 as a gas forming agent. Drug entrapment efficiency, drug loading, floating properties, drug release, crystallinity and release kinetic as well as morphology of the prepared beads were also assessed.

Results: Drug entrapment efficiency ranged between 61.7 - 93.1% for the prepared formulations whereas gas forming based beads exhibited more value of drug loading comparing with the silicate based beads. The silicate based beads showed slower release pattern, compared to the gas forming based beads due to network structure strengthening effect of the calcium silicate. Furthermore, the gas forming based beads had shorter initial buoyancy lag time, owing to the fact that the NaHCO3 produced larger pores than those of silicate treated ones. Kinetically, release pattern of MZ in simulated gastric fluid from the beads fitted best to Reciprocal powered time, Weibull and log-probability models with the respect OE values of 4.50, 5.30 and 7.76.

Conclusion: On the whole, by altering the amount of three formulation variables in formulations, the characterization of the beads could be controlled. By and large, these systems can float in the gastric condition and control the drug release from the beads with a definite kinetic of release.