Modulating the properties of sunflower oil based novel emulgels using castor oil fatty acid ester: prospects for topical antimicrobial drug delivery.

The current study describes the effect of polyglycerol polyricinoleate (PGPR) on the properties of sunflower oil and span-40 based emulgels. The prepared emulgels contained PGPR in varied concentrations. The microstructure of the emulgels was characterized by bright-field microscopy. The molecular interactions amongst the components of the emulgels were studied using FTIR spectroscopy. The flow and mechanical behaviors of the emulgels were studied using cone-and-plate viscometer and static mechanical tester, respectively. The efficiency of the metronidazole-loaded emulgels as antimicrobial formulations was tested in vitro. E. coli was used as the model microorganism for the antimicrobial study. The emulgels were also explored for iontophoretic delivery applications. The biocompatibility of the emulgels was tested using human keratinocytes (HaCaT). The microscopic evaluation of the emulgels indicated formation of biphasic formulations. FTIR studies suggested a decrease in the hydrogen bonding amongst the components of the emulgels as the concentration of the PGPR was increased. Viscosity studies indicated shear-thinning property of the emulgels. An increase in the PGPR concentration resulted in the reduction in the mechanical properties of the emulgels. Incorporation of PGPR resulted in the decrease in the drug released (both passive and iontophoresis) from the emulgels. The emulgels were found to be cytocompatible in the presence of keratinocytes. The drug loaded emulgels showed good antimicrobial activity against E. coli. In gist, the developed emulgels can be tried for controlled delivery of antimicrobial drugs. The physical and the release properties of the emulgels can be modulated by incorporating PGPR in varied proportions.