Introduction: Intravascular catheter skin insertion site dressings, incorporating chlorhexidine gluconate (CHG) are designed to reduce the risk of catheter-related bloodstream infection. However, the efficacy of these dressings in delivering CHG onto and into the upper layers of the skin, (which may determine their antimicrobial efficacy) has not been studied.
Method: CHG delivery onto human skin from an aqueous gel (3M™ Tegaderm™ CHG IV Securement dressing) and dry urethane disk (Biopatch®) was determined using a donor human skin model. After 24-h application of CHG containing dressings onto skin, the concentration and depth of CHG skin permeation was determined in sequential skin sections. 
Results: Residual CHG in skin samples without any dressings applied, was detected. This originated from the donor patient’s pre-operative skin antisepsis. Additional CHG was detected after application of CHG-containing dressings. There was no significant difference between the two dressings in terms of the amount of CHG delivered overall from the surface to skin depth of 2000μm, although a higher concentration was present in the urethane disk. The percentage of applied CHG that was delivered into the skin was over 10-fold higher after application of the aqueous gel in comparison to the disk. A greater percentage of the CHG applied was delivered into the top 100μm of skin from the aqueous gel as compared to the urethane disk (p=0.043). The estimated level of CHG in the top 100μm of skin reached over 160 mg/L with the application of the aqueous gel and 90mg/L following the urethane disk.
Discussion & Conclusions: Permeation of CHG into full thickness donor skin from an aqueous gel or urethane disk were similar although the disk initially contained a higher concentration of CHG. These results highlight that not only the amount of CHG applied but also the method of delivery are important considerations when designing antiseptics.

Laboratory evaluation of chlorhexidine delivery into donor skin from the Biopatch® and 3M™ Tegaderm™ CHG IV Securement dressings