Preparation and characterization of novel carbopol based bigels for topical delivery of metronidazole for the treatment of bacterial vaginosis

• Novel bigels were prepared using sorbitan monostearate organogel and carbopol 934 hydrogel.
• The developed bigels were stable and biocompatible.
• Metronidazole loaded bigels showed diffusion-mediated drug release.
• Bigels showed good antimicrobial efficacy in comparison with the marketed gel.

The current study reports the development of bigels using sorbitan monostearate-sesame oil organogel and carbopol 934 hydrogel. The microstructures and physicochemical properties were investigated by microscopy, viscosity measurement, mechanical analysis and differential scanning calorimetry analysis. Fluorescence microscopy confirmed the formation of oil-in-water type of emulsion gel. There was an increase in the strength of the bigels as the proportion of the organogel was increased in the bigels. The developed bigels showed shear-thinning flow behavior. The stress relaxation study suggested viscoelastic nature of the bigels. The developed bigels were biocompatible. Metronidazole, drug of choice for the treatment of bacterial vaginosis, loaded bigels showed diffusion-mediated drug release. The drug loaded gels showed good antimicrobial efficiency against Escherichia coli. In gist, the developed bigels may be used as delivery vehicles for the vaginal delivery of the drugs.