Evaluation of drug release kinetics and physico-chemical characteristics of metronidazole floating beads based on calcium silicate and gas-forming agents

Abstract

In the present investigation metronidazole-loaded alginate beads consisting of calcium silicate as a porous carrier or NaHCO₃ as a gas-forming agent were prepared for local eradication of Helicobacter Pylori. Gelation method was used for preparation of conventional sodium alginate beads. Drug entrapment efficiency, drug loading, floating properties, drug release, crystallinity and release kinetic as well as morphology of the prepared beads were assessed. The silicate based beads showed slower release pattern, compared to the gas-forming 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. Drug entrapment efficiency ranged between 61.7 and 93.1% for the prepared formulations. The maximum value of drug loading for gas-forming and silicate-based beads were 66.64% and 34.97%, respectively. Kinetically, release pattern of metronidazole in simulated gastric fluid from the beads fitted best to Reciprocal powered time, Weibull and log-probability models with the respect overall mean percentage error values of 4.50, 5.30 and 7.76. By and large, these systems can float in the gastric condition and control the drug release from the beads.

Keywords::

• Metronidazole
• calcium silicate
• alginate beads
• kinetic of release
• drug loading

Acknowledgments

The authors would like to thank the Drug Applied Research Center of Tabriz University of Medical Sciences for financial support of this study (Grant Number 86/91).

Declaration of interest

Support of this work by the Drug Applied Research Center of Tabriz University of Medical Sciences is gratefully acknowledged.