Concomitant and controlled release of furazolidone and bismuth(III) incorporated in a cross-linked sodium alginate-carboxymethyl cellulose hydrogel

The combination of bismuth(III) citrate and the antibiotic furazolidone (FDZ) results in a synergetic effect on Helicobacter pylori eradication. However, the problems associated with their oral administration are challenges to overcome. Thus, in the present study, sodium alginate (SA)/carboxymethyl cellulose (CMC) blend hydrogels (SC) were developed for concomitant and controlled release of furazolidone and bismuth(III). The blank formulation (SCblank) and the three drug-loaded hydrogels (SCFDZ, SCBi, and SCFDZ-Bi) were prepared by casting method and characterized by infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, and X ray powder diffraction analyses. The swelling equilibrium and cumulative release amounts of FDZ and Bi3+ have indicated distinct behaviors of the hydrogels to different pH values. The bismuth-containing sample (SCFDZ-Bi) presents more resistance to degradation on a neutral solution and shows more suitable properties for controlled drug release than the sample without bismuth (SCFDZ). Microbiological studies, using Escherichia coli as a model, show bacteria viability reduction in presence of the drug-loaded samples. The developed system containing furazolidone and bismuth(III) appears to be promising for oral administration with concomitant and controlled release of these drugs aimed at the pharmacological treatment of gastrointestinal disorders.