The concentration of CHG recovered from the skin at various depths is shown in Fig.
1. In the CHG/IPA alone group, there was a significant decrease in the CHG concentration with every 100 μm section skin between 100 μm and 700 μm below the skin surface (
P = 0.028, 0.012, <0.001, 0.009, 0.008 and 0.026 respectively). For the CHG/IPA with 1,8-cineole group, CHG levels decreased for every 100 μm depth of skin between 200 μm and 600 μm below the skin surface (
P = 0.026, 0.002, 0.010 and 0.041 respectively). The concentration of CHG in the skin was on average significantly higher in both the CHG/IPA and CHG/IPA with 1,8-cineole groups compared to background levels (
P = 0.015 and
P = 0.020, respectively). The size of the effect varied according to the depth of penetration into the skin (
P = 0.004 and
P = 0.011, respectively). The difference between background and treatment values tended to decrease with increasing depths. The concentration of CHG in the skin was on average significantly higher in the CHG/IPA with 1,8-cineole group compared to the CHG/IPA alone (
P = 0.042). However the size of the effect did not vary according to the depth of penetration into the skin (
P = 0.311), with there being no evidence that the true effect varied with depth. The concentrations of CHG in the skin following application of the CHG solution containing 1,8-cineole were on average 33.3% higher (95%, CI 1.5% - 74.9%) than when the CHG solution without 1,8-cineole was applied.