Regional variability in stratum corneum reactivity to antiseptic formulations

Skin does not react in an identical way to the action of chemicals over all anatomic sites. Accordingly, distinct regional differences have been described in relation to irritancy. The present study assesses the regional variations of stratum corneum (SC) reactivity to 3 proprietary antiseptic solutions (povidone iodine (PVP-I), 70 mg/ml and 100 mg/ml, and chlorhexidine digluconate 50 mg/ml) using the corneoxenometry (CXM) bioassay. SC was harvested from the volar forearm, the forehead and the back in 30 young adults. Each SC sample was covered by one of the neat test product or deionized water for 2 hr at 20 degrees C. The intrinsic staining property of each antiseptic on SC was assessed by reflectance colorimetry. For the CXM bioassay, samples were then stained by a toluidine blue-basic fuschin solution in order to show protein denaturation induced by the test products. The colorimetric index of mildness (CIM = L*- Chroma C*) was measured by colorimetry. Data show that PVP-I 100 mg/ml was the least reactive antiseptic to the SC. It was significantly milder than the 2 other antiseptics.