Penetration of chlorhexidine into human skin

Abstract

This study evaluated a model of skin permeation to determine the depth of delivery of chlorhexidine into full-thickness excised human skin following topical application of 2% (wt/vol) aqueous chlorhexidine digluconate. Skin permeation studies were performed on full-thickness human skin using Franz diffusion cells with exposure to chlorhexidine for 2 min, 30 min, and 24 h. The concentration of chlorhexidine extracted from skin sections was determined to a depth of 1,500 microm following serial sectioning of the skin using a microtome and analysis by high-performance liquid chromatography. Poor penetration of chlorhexidine into skin following 2-min and 30-min exposures to chlorhexidine was observed (0.157 +/- 0.047 and 0.077 +/- 0.015 microg/mg tissue within the top 100 microm), and levels of chlorhexidine were minimal at deeper skin depths (less than 0.002 microg/mg tissue below 300 microm). After 24 h of exposure, there was more chlorhexidine within the upper 100-microm sections (7.88 +/- 1.37 microg/mg tissue); however, the levels remained low (less than 1 microg/mg tissue) at depths below 300 microm. There was no detectable penetration through the full-thickness skin. The model presented in this study can be used to assess the permeation of antiseptic agents through various layers of skin in vitro. Aqueous chlorhexidine demonstrated poor permeation into the deeper layers of the skin, which may restrict the efficacy of skin antisepsis with this agent. This study lays the foundation for further research in adopting alternative strategies for enhanced skin antisepsis in clinical practice.

Figures

FIG. 1.

Diagram of Franz diffusion cell. The receptor compartment was filled with PBS, which was kept at 37°C by circulating water jacket. The skin was mounted between the receptor and donor compartments and clamped. The test drug was aliquoted into the donor compartment. The drug diffused through the skin was sampled by removing receptor fluid via the sampling port.

FIG. 2.

Penetration profile showing the concentration and location of chlorhexidine (μg/mg tissue) in excised human skin after 2 min or 30 min of exposure to aqueous 2% (wt/vol) chlorhexidine digluconate (mean ± standard error; n = 15).

FIG. 3.

Penetration profile showing the concentration and location of chlorhexidine (μg/mg tissue) in excised human skin after 2 min or 30 min (n = 15) or 24 h (n = 30) of exposure to aqueous 2% (wt/vol) CHG (mean ± standard error).