Abstract

Hand hygiene has proven to be one of the most effective practices to prevent the spread of infectious microorganisms. Povidone-iodine (PVP-I) is one of the most effective antiseptics for this purpose. In this study, bigels (hybrid systems of oleogel and hydrogel) loaded with PVP-I were prepared varying the oleogel:hydrogel ratio 40:60 and 60:40 (called: BPVP-I O:H-40:60 and BPVP-I O:H-60:40 respectively). The oleogel was prepared with a base of extra virgin olive oil, beeswax, and alpha-tocopherol; the hydrogel was prepared with deionized water, hydroxyethylcellulose, and PVP-I at 5% (w/v). Bigels were characterized by visual appearance, microstructure, rheological behavior, and molecular ordering. Iodine (I-2) release from the bigels was analyzed through kinetic models. The antibacterial effectiveness was evaluated with the in vivo finger-streak technique on an agar surface, using ten volunteers for treatment. Results show that BPVP-I O:H-40:60 had a soft and smooth texture, while BPVP-I O:H-60:40 presented a harder and firmer texture. Microscopic studies showed an interconnected network of pores and the continuous phase formation of bigels for BPVP-I O:H-40:60 and hydrogel-in-oleogel type bigels for BPVP-I O: H-60:40. Structural differences altered the viscoelastic behavior of the bigels. Bigels with a higher hydrogel concentration (BPVP-I O:H-40:60) were less rigid, while bigels with a higher oleogel concentration (BPVP-I O:H-60:40) had the greatest resistance to deformation. The Weibull model equation best fitted the release data of I-2. I-2 release kinetic data showed a Fickian diffusion behavior. The antiseptic action of bigels reduces bacterial growth on the fingers 1 h after application. These results suggest that both bigels formulated can act as promising alternatives to hand antiseptic products.