Clinical Testing of Topical Antiseptics

Consumer Antiseptic TEsting

Consumer antiseptics are typically sold over-the-counter (OTC) in drug stores, grocery stores, and other common retailers for home and public use (i.e. daycares, schools, airports, offices) to help prevent the spread of infections microorganisms. The two primary types of Consumer Antiseptics are antiseptic washes and antiseptic rubs.

Antimicrobial Wash Products include antibacterial hand washes, hand soaps, and body washes. These antiseptic products are lathered with the aid of water, and then the hands are rinsed and dried. The efficacy of these products is currently under review.2 The FDA is currently reviewing OTC antiseptics, and has published a final ruling that amends the 1994 Tentative Final Monograph (TFM)3 and has identified certain active ingredients used in consumer antiseptic washes that are not generally recognized as safe and effective (GRAS/GRAE).4 The antimicrobial effectiveness of antiseptic wash products can be tested following procedures based on ASTM Standards such as E2870, E2784, E2276 (bacteria specific), E1838 (virus specific), and E2613 (fungi specific).

Antimicrobial Rub Products, like the alcohol-based hand rubs and other leave-on formulations, are designed to be applied full strength, rubbed in until dry, and used without water rinsing. They are a convenient alternative to hand washing, especially when a water source is not available. These products may also be tested for antimicrobial efficacy using protocols based on ASTM Test Methods such as E2276, E1838, and E2613. In addition, the FDA is now proposing an amendment to the TFM that would include additional in vitro effectiveness data be obtained in order to support GRAS/GRAE branding for consumer antimicrobial rub active ingredients.5

Overview of Consumer antiseptic Efficacy Test Methods

The antiseptic efficacy test methods for consumer hand wash and hand rub products typically determine the activity of the products on transient microorganisms on the hands and report the results in terms of bacterial log reductions to support the antimicrobial claims. The in vivo protocols test the ability of the products to remove specific types of bacteria, viruses, or fungi from experimentally contaminated skin (i.e. finger tips, palms), using appropriate drying conditions, controls, and replicates. The level of contamination is often five to ten times higher than the performance required.

ASTM methods E2276, E1838, and E2613 for the effectiveness of antiseptic products for the elimination of bacteria, viruses, and fungi respectively, all use a fingerpad method.6,7,8 In this method a specified amount of a test inoculum suspension is placed on each fingerpad and allowed to dry. The contaminated area is then exposed to either a control or to an antimicrobial product for the specified contact time. The microorganisms surviving on the fingerpads are collected via extraction and the recovery fluids are assayed. The control and test substance results are compared and percent or log10 reductions in the number of viable microorganisms due to exposure to the antiseptic product are reported. Fingerpad and whole hand methods give comparable results.

When choosing the contaminant microorganisms, the subject and experimenter safety, the ease of microorganism growth, recovery and identification, and the potential to spread from contaminated hands are considered. For bacteria, Serratia marcescens, Escherichia coli, Acinetobacter baumannii, Staphylococcus aureus, and Staphylococcus epidermidis are commonly used. Typical viruses include, Human Adenovirus, Hepatitis A Virus, Human Rotavirus, Rhinovirus, and Feline Calicivirus (an approved surrogate virus for Human Norovirus). Candida albicans and Aspergillus niger, representing non-filamentous or yeast like fungi and filamentous fungi respectively, are typically chosen for fungi testing.

strenGths of Consumer Antisepsis Testing

Testing speed, ease of microorganism recovery, and similarity to real life situations are potential test methodology strengths. For example, an advantage of fingerpad testing methods such as ASTM E2276, E1838, and E2613, is that there are ten test areas per subject, making it quick and easy to incorporate multiple controls and replicates. Additionally, the method only requires approximately 100 μL of the micororganism suspension per test. ASTM method E2870 has advantages over methods such as E2784 in that the E2870 allows for direct comparisons between two formulations and it uses a mechanical scrubbing machine which provides a more efficient recovery of test bacteria.

Eurofins CRL will work with you to understand your product application and limitations and will help you choose the best test methods to meet your needs.

weaknesses of Consumer Antisepsis Testing

As with any test method that simulates actual use, it is challenging to take all “real life” factors into account, and the test results will have limitations due to the assumptions used for the testing protocol. For example, Palmar methods do not reflect the intended use of wash products and do not account for microorganisms which may be under the fingernails4. Tests also may be designed for use only with specific types of products. For example, the fingerpad tests described above are designed for use with hand wash and hand rub products, but are not designed to test surgical hand scrubs or peroperative skin preparations.

Eurofins CRL will work with you to identify appropriate procedures and test conditions for testing protocols in order to meet the requirements of the test method and observe the appropriate testing conditions based on the test product’s formulation.

why Eurofins CRL?

Eurofins CRL is a contract testing laboratory designed to support the hand hygiene and infection control industry. The ECRL laboratory offers testing in compliance with current FDA, Good Laboratory Practice (GLP), and Good Clinical Practice (GCP) regulations.  Clients are welcome to tour the lab, observe studies, and audit the lab's quality system. The lab is staffed by a capable, friendly group of scientists, mostly microbiologists.  We understand what our clients need:  fairly priced testing services, done accurately and reported quickly. 

references:

  1. Public domain photos of Handwash and Handsanitizer from FDA website. http://www.fda.gov/Drugs/DrugSafety/InformationbyDrugClass/ucm444681.htm
  2. Topical Antiseptic Products: Hand Sanitizers and Antibacterial Soaps http://www.fda.gov/Drugs/DrugSafety/InformationbyDrugClass/ucm444681.htm
  3. Federal Register Notice: Tentative Final Monograph for OTC Healthcare Antiseptic Drug Products – June 17, 1994 http://www.fda.gov/ohrms/dockets/ac/05/briefing/2005-4184B1_01_16-FDA-TAB15.pdf
  4. Safety and Effectiveness of Consumer Antiseptics; Topical Antimicrobial Drug Products for Over-the-Counter Human Use. A Rule by the Food and Drug Administration on 09/06/2016. https://www.federalregister.gov/documents/2016/09/06/2016-21337/safety-and-effectiveness-of-consumer-antiseptics-topical-antimicrobial-drug-products-for
  5. Safety and Effectiveness of Consumer Antiseptics; Topical Antimicrobial Drug Products for Over-the-Counter Human Use; Proposed Amendment of the Tentative Final Monograph; Reopening of Administrative Record A Proposed Rule by the Food and Drug Administration on 06/30/2016. https://www.federalregister.gov/documents/2016/06/30/2016-15410/safety-and-effectiveness-of-consumer-antiseptics-topical-antimicrobial-drug-products-for
  6. ASTM E2276. Standard Test Method for Determining the Bacteria-Eliminating Effectiveness of Hygienic Handwash and Handrub Agents Using the Fingerpads of Adults. https://www.astm.org/Standards/E2276.htm
  7. ASTM E1838. Standard Test Method for Determining the Virus-Eliminating Effectiveness of Hygienic Handwash and Handrub Agents Using the Fingerpads of Adults. https://www.astm.org/Standards/E1838.htm
  8. ASTM E2613. Standard Test Method for Determining the Fungus-Eliminating Effectiveness of Hygienic Handwash and Handrub Agents Using the Fingerpads of Adults. https://www.astm.org/Standards/E2613.htm