In vivo efficacy of an alcohol-based surgical hand disinfectant containing a synergistic combination of ethylhexylglycerin and preservatives

Patch Testing to Ethylhexylglycerin: The North American Contact Dermatitis Group Experience, 2013-2018

BACKGROUND

Ethylhexylglycerin (EHG) is a recently recognized contact allergen.

OBJECTIVE

The aims of the study were to characterize individuals with positive patch test reactions to EHG and to analyze reaction strength, clinical relevance, and allergen sources.

METHODS

This study was a retrospective analysis of the patients patch tested to EHG (5% petrolatum) by the North American Contact Dermatitis Group (2013-2018).

RESULTS

Of 15,560 patients tested to EHG, 39 (0.25%) had positive (final interpretation of "allergic") reactions. Most were female (71.8%) and/or older than 40 years (76.9%). There were no statistically significant differences between age, sex, or atopic history when compared with EHG-negative patients. The most common anatomic sites of dermatitis were the face (28.2%) and scattered generalized distribution (25.6%). Most EHG-positive reactions were + (35.9%) or ++ (33.3%). Current clinical relevance was high (79.5%); none, however, were related to occupation. Personal care products were the most common source of exposure to EHG (59.0%).

CONCLUSIONS

Ethylhexylglycerin is a rare contact allergen; the positive frequency of 0.25% is similar to other low allergenic preservatives including parabens, benzyl alcohol, and phenoxyethanol. The patch test concentration of 5.0% seems to be nonirritating. Although relatively uncommon, EHG reactions were usually clinically relevant (79.5%), often because of moisturizers/lotions/creams.

Virucidal Action Mechanism of Alcohol and Divalent Cations Against Human Adenovirus

Hygiene and disinfection practices play an important role at preventing spread of viral infections in household, industrial and clinical settings. Although formulations based on >70% ethanol are virucidal, there is a currently a need to reformulate products with much lower alcohol concentrations. It has been reported that zinc can increase the virucidal activity of alcohols, although the reasons for such potentiation is unclear. One approach in developing virucidal formulations is to understand the mechanisms of action of active ingredients and formulation excipients. Here, we investigated the virucidal activity of alcohol (40% w/v) and zinc sulfate (0.1% w/v) combinations and their impact on a human adenovirus (HAdV) using, nucleic acid integrity assays, atomic force microscopy (AFM) and transmission electron microscopy (TEM). We observed no difference in virucidal activity (5 log₁₀ reduction in 60 min) against between an ethanol only based formulation and a formulation combining ethanol and zinc salt. Furthermore, TEM imaging showed that the ethanol only formulation produced gross capsid damage, whilst zinc-based formulation or formulation combining both ethanol and zinc did not affect HAdV DNA. Unexpectedly, the addition of nickel salt (5 mM NiCl₂) to the ethanol-zinc formulation contributed to a weakening of the capsid and alteration of the capsid mechanics exemplified by AFM imaging, together with structural capsid damage. The addition of zinc sulfate to the ethanol formulation did not add the formulation efficacy, but the unexpected mechanistic synergy between NiCl₂ and the ethanol formulation opens an interesting perspective for the possible potentiation of an alcohol-based formulation. Furthermore, we show that AFM can be an important tool for understanding the mechanistic impact of virucidal formulation.

Ethylhexylglycerin: a low-risk, but highly relevant, sensitizer in 'hypo-allergenic' cosmetics

BACKGROUND

Ethylhexylglycerin is a relatively new cosmetic ingredient that is used for its surfactant, emollient, skin-conditioning and antimicrobial properties. Since 2002, it has been occasionally reported as a contact allergen.

OBJECTIVES

To report on 13 patients who presented with allergic contact dermatitis caused by ethylhexylglycerin, evaluated at two Belgian university patch test clinics during the period 1990-2015.

PATIENTS AND METHODS

The patients were patch tested with the European baseline series, a cosmetic series, and - if indicated - additional series. Both the cosmetic products used and their single ingredients were patch tested.

RESULTS

All but one of the ethylhexylglycerin-allergic patients were female, with a median age of 43 years (range: 29-81 years), most often suffering from dermatitis on the face, and sometimes on the hands and/or axillae. As the culprit products, leave-on cosmetics were identified, including a high number of proclaimed 'hypo-allergenic' and 'preservative-free' facial creams, sun protection creams, and deodorants.

CONCLUSIONS

Ethylhexylglycerin is a rare, but highly relevant, cosmetic sensitizer, even in those products advertised to be safe for consumers. Targeted patch testing with ethylhexylglycerin 5% pet. is very useful, and routine patch testing in a cosmetic series may be considered. Higher test concentrations might be indicated in selected cases.

Evaluation of an Alcohol-Based Surgical Hand Disinfectant Containing a Synergistic Combination of Farnesol and Benzethonium Chloride for Immediate and Persistent Activity Against Resident Hand Flora of Volunteers and With a Novel In Vitro Pig Skin Model

Objective.

To evaluate the immediate, persistent and sustained in vivo activity of an alcohol-based surgical hand disinfectant, consisting of a zinc gel and a preservative system containing a synergistic combination of farnesol and benzethonium chloride (ZBF disinfectant), and to develop a pig skin model for in vitro evaluation of the immediate and persistent efficacy of alcohol-based surgical hand disinfectants against resident hand flora.

Design.

The in vivo immediate, persistent, and sustained activity of ZBF disinfectant was evaluated using human volunteers and the “glove-juice” method described in the US Food and Drug Administration's Tentative Final Monograph (FDA-TFM) for Healthcare Antiseptic Products. A novel in vitro pig skin model was developed to compare the immediate and persistent activity of alcohol-based surgical hand disinfectants against resident flora usingStaphylococcus epidermidisas the test organism. Four alcohol-based surgical hand disinfectants were evaluated using this model.

Results.

The results for the ZBF disinfectant exceed the FDA-TFM criteria for immediate, persistent, and sustained activity required for surgical hand disinfectants. The reduction factors for the 4 hand disinfectants obtained using the pig skin model show good agreement with the log10reductions in concentrations of hand flora obtained using human volunteers to test for immediate and persistent activity.

Conclusion.

The ZBF disinfectant we evaluated met the FDA-TFM criteria for surgical hand disinfectants. The immediate and persistent efficacy of the surgical hand disinfectants evaluated with the novel pig skin model described in this study shows good agreement with the results obtained in vivo.

Safety assessment of alkyl glyceryl ethers as used in cosmetics

Alkyl glyceryl ethers function mostly as skin-conditioning agents in cosmetic products applied to the skin and hair. The Cosmetic Ingredient Review expert panel reviewed the available animal toxicity and clinical data, including the low dermal absorption, and concluded that the alkyl glyceryl ethers are safe in the present practices of use and concentration described in this safety assessment.

Development of a health care personnel handwash with 6-hour persistence

BACKGROUND

Health care handwashes/sanitizers help prevent the spread of infection. Many are alcohol-based, providing immediate microbial kill. Few contain persistence factors for residual antimicrobial effects. We conducted multiple studies on Viacydin-Containing Alcohol Sanitizer (VCAS) to evaluate antimicrobial properties and skin friendliness.

METHODS

The potential of VCAS to cause use related skin problems was examined by repeated applications over a 3-week period. Excessive handwashing compared effects of VCAS on the skin barrier with that of other handwash products. Antimicrobial range, immediate kill rates, and resistance development were assessed as was the potential for continued antimicrobial activity over an extended period following product use.

RESULTS

Our data showed the VCAS formula has broad, rapid antimicrobial efficacy without promoting microbial resistance. VCAS is mild to skin. Antimicrobial persistence testing showed that VCAS remained effective up to 6 hours postapplication.

CONCLUSION

VCAS was superior to or at parity with on-market products, exhibited substantial residual effects and persistence up to 6 hours, and was safe and well tolerated. These results provide strong evidence for the value of VCAS to help prevent and eliminate pathogen contamination of the hands.