Sustained antibacterial effect of a hand rub gel incorporating chlorhexdine-loaded nanocapsules (Nanochlorex®)

In the present study, an original chlorhexidine-loaded nanocapsule-based gel (Nanochlorex®) was tested as hand rub gel against the resident skin flora in comparison with 2-propanol 60% (v/v) and 62% (v/v) ethanol-based gel (Purell®). After 30-s hand rub, the immediate bactericidal effect of Nanochlorex® was found comparable to 2-propanol 60% (v/v) (reduction factor, RF: 0.30 ± 0.35 versus 0.38 ± 0.55, P > 0.05) against aerobic bacteria, whereas the post-values of surviving anaerobes were shown significantly lower from Nanochlorex® (P < 0.001) and insignificant from 2-propanol 60% (v/v) (P > 0.05). Sustained antibacterial effect of Nanochlorex® was confirmed against the resident and transient hand flora in two sets of experiment. In the first, the results obtained with the glove-juice technique showed that the bactericidal effect induced by Nanochlorex® hand rub persisted throughout 3-h period, while Purell® failed to reduce significantly the post-values of surviving bacteria. In the second, repeated artificial contaminations with Staphylococcus epidermidis was carried out onto ex vivo human skin pre-treated by either Nanochlorex® or Purell® for 5 min, then maintained in cell diffusion apparatus for 4 h. The log10 reduction of surviving bacteria was significantly higher with Nanochlorex® than that determined with Purell® after three successive contaminations (from ∼5.5 to 1.5 log10 reduction for Nanochlorex® between the first and the third contamination; ∼1 log10 reduction for Purell® throughout the experiment), confirming the sustained antibacterial effect of chlorhexidine-loaded nanocapsule-based gel. The immediate and sustained antibacterial effect of Nanochlorex® was explained by chlorhexidine carrier system which improved the drug targeting to bacteria and reduced from osmotic gel further bacterial growth on the skin. Nanochlorex® might constitute a promising approach for hygienic hand disinfection in care practice performing multiple procedures.