Hybrid in vitro diffusion cell for simultaneous evaluation of hair and skin decontamination: temporal distribution of chemical contaminants.

Most casualty or personnel decontamination studies have focused on removing contaminants from the skin. However, scalp hair and underlying skin are the most likely areas of contamination following airborne exposure to chemicals. The aim of this study was to investigate the interactions of contaminants with scalp hair and underlying skin using a hybrid in vitro diffusion cell model. The in vitro hybrid test system comprised "curtains" of human hair mounted onto sections of excised porcine skin within a modified diffusion cell. The results demonstrated that hair substantially reduced underlying scalp skin contamination and that hair may provide a limited decontamination effect by removing contaminants from the skin surface. This hybrid test system may have application in the development of improved chemical incident response processes through the evaluation of various hair and skin decontamination strategies.

Evaluation of a new topical skin protectant (RD1433) for the prevention and treatment of incontinence-associated dermatitis.

Context Incontinence-associated dermatitis (IAD) is a type of moisture-associated dermatitis caused by repeated skin exposure to urine or stool. A product that could mitigate such symptoms would have a significant impact on cost of care and patients' quality of life. Objective This study compared the clinical efficacy of RD1433 and a comparator product (Vaseline®) in preventing and treating experimental IAD skin lesions. Materials and methods For the "prevention" part of the study, skin sites in eight human volunteers were treated daily for 5 d with either RD1433 or Vaseline® immediately prior to synthetic urine exposure. In the "treatment" part, exposure to synthetic urine was substituted for Vaseline® or RD1433 application on the first 2 d to promote the development of skin lesions prior to the application of the products from day three. Product efficacy was quantified by visual scoring and an array of biophysical instruments. Results Both RD1433 and Vaseline® significantly reduced lesion progression when applied as a prophylactic. When applied as a treatment (following establishment of skin lesions), RD1433 demonstrated a statistically significant improvement in several measures of skin function whereas there was no statistically significant improvement following treatment with Vaseline®. Conclusions The findings of this study suggest that RD1433 may be superior to Vaseline® in the prevention and treatment of experimental IAD lesions. Clearly, further work is required to establish the efficacy of RD1433 with patients in a clinical environment.

Optimisation of a dosing regime for a topical skin protectant (barrier cream).

CONTEXT: Topical skin protectants (barrier creams) have the potential to reduce or enhance the severity of dermal lesions following exposure to allergens or irritants. Therefore, it is essential that such products are subject to appropriate clinical evaluation prior to marketing. Consequently, it is important to accurately define a dosing regime in order to assess test products under appropriate conditions. OBJECTIVE: In this study, we extended the use of a standard rubefacient (methyl nicotinate; MN) assay to establish the optimum thickness and duration of action of a novel barrier cream (RD1433). White petroleum jelly (Vaseline(®)) was used as a comparator product. METHODS: The dermal response to MN was measured on the volar forearm skin of volunteers (n = 12; average age 47.5 years) using an array of biophysical instruments and visual scoring. When applied at a nominal thickness of 0.1 mm, RD1433 retained effectiveness against MN for up to six hours. In contrast, Vaseline(®) was relatively ineffective. Moreover, RD1433 provoked no measurable signs of irritation and so can be considered acceptable for further clinical evaluation. CONCLUSION: Future clinical studies using RD1433 should be based on topical application of a 0.1 mm thickness layer every six hours.