Keith D. Ertel

Efficacy of Organic Acids in Hand Cleansers for Prevention of Rhinovirus Infections

ABSTRACT Direct hand-to-hand contact is an important mechanism of transmission of rhinovirus infection. The rhinoviruses are inactivated at a low pH. A survey of organic acids in vitro revealed that these compounds have antirhinoviral activity that persists for at least 3 h after application to the skin. In additional studies of salicylic acid (SA) and pyroglutamic acid (PGA), the hands of volunteers were contaminated with rhinovirus at defined times after application of the acid, and then volunteers attempted to inoculate the nasal mucosa with one hand and quantitative viral cultures were done on the other hand. In one study, 3.5% SA or 1% SA with 3.5% PGA was compared with controls 15 min after application to assess the efficacy of the inactivation of virus and prevention of infection. Virus was recovered from the hands of 28 out of 31 (90%) of the volunteers in the control group compared to 4 out of 27 (15%) and 0 out of 27 in the groups administered 3.5 and 1% SA, respectively (P < 0.05). Rhinovirus infection occurred in 10 out of 31 (32%) of the controls and 2 out of 27 (7%) of volunteers in both treatment groups (P < 0.05 compared with control). In a second study, the efficacy of 4% PGA was evaluated 15 min, 1 h, and 3 h after application. Significantly fewer volunteers had positive hand cultures at all time points compared with the control group, but the proportion that developed rhinovirus infection was not significantly reduced. These results suggest the feasibility of the prevention of rhinovirus transmission by hand treatments that are virucidal on contact and have activity that persists after application.

Leg wash protocol to assess the skin moisturization potential of personal cleansing products.

Many personal cleansers claim to provide a skin moisturization benefit, but there has been relatively little discussion in the scientific literature of the clinical methods that provide the basis for such claims. We have developed a leg wash method to assess the dry skin improvement potential of personal cleansing products. The protocol is performed on ’natural’ dry leg skin to avoid potential confounds that may result from applying cleansers to soap‐damaged skin. Washes are conducted over a period of days or weeks, with visual and instrumental assessments performed at various times throughout the period to characterize products’ short‐term and cumulative skin effects. Studies conducted with a variety of personal cleansing technologies demonstrate the method’s ability to discriminate products on the basis of their dry skin improvement potential. Further, results from a series of eleven leg wash studies conducted with the same treatment pair under different test conditions (time of year, test facility, expert grader) demonstrate the protocol’s robustness. The data generated under this protocol show that personal cleansing products differ widely in their ability to improve dry skin. Our results indicate that there is a wide range of efficacy among moisturizing personal cleansing products, with some products delivering a significant dry skin improvement benefit even for periods as long as 24 hours.

Fluorescence spectral imaging of dihydroxyacetone on skin in vivo.

Dihydroxyacetone (DHA) has been proposed as a potential alternative to dansyl chloride for use as a fluorescence marker on skin to assess stratum corneum turnover time in vivo. However, the fluorescence from DHA on skin has not been adequately studied. To address this void, a noninvasive, noncontact spectral imaging system is used to characterize the fluorescence spectrum of DHA on skin in vivo and to determine the optimal wavelengths over which to collect the DHA signal that minimizes the contributions from skin autofluorescence. The DHA‐skin fluorescence signal dominates the 580–680 nm region of the visible spectrum when excited with ultraviolet radiation in the 320–400 nm wavelength region (UVA). An explanation of the time‐dependent spectral features is proposed in terms of DHA polymerization and binding to skin.

Personal Cleansers: Irritation and Moisturization

Soaps are among the most widely used personal care products, accounting for approximately half of the personal hygiene market in 1996 with a value of over

Niacinamide-containing facial moisturizer improves skin barrier and benefits subjects with rosacea.

2 billion (Mcardle, 1997). Soap has been used for personal cleansing since antiquity. The past few decades have witnessed the introduction of cleansing bars based in part or in toto on synthetic surfactant systems. More recently, the industry has seen a rise in the popularity of body washes. Many of these body washes are based entirely on synthetic surfactant systems to offer “ultramild” cleansing. Additionally, a number of bar and body wash products now claim to offer consumers additional convenience by not only cleansing, but also moisturizing the skin