Comparison of the efficacy and drying times of liquid, gel and foam formats of alcohol-based hand rubs.

BACKGROUND

Hand rubs containing alcohols such as isopropanol (IPA) or ethanol (EtOH) are widely used for hygienic hand disinfection, and are presented in different formats (i.e. liquid, gel or foam).

AIM

To determine if there is any difference in efficacy between these two active ingredients in the three formats. In addition, an assessment of the drying time was undertaken. Two non-commercial, 'standard' formulations were tested in each format: one containing 60% IPA, and the other containing 80% EtOH.

METHODS

EN 1500 tests were performed with 20 volunteers to assess efficacy. The reference product was 2 x 3 mL of 60% IPA for 60 s, as described in EN 1500 (2013). The test products were 3 mL of liquid, gel or foam format; one full EN 1500 test was performed for each formulation (60% IPA and 80% EtOH). To assess drying time, two different volumes (1.5 and 3.0 mL) of the test formulations in liquid, gel or foam format were applied to the hands of 15 volunteers. Volunteers self-reported when their hands were dry; at the end of the test, the volunteers were asked to rate the time taken to dry on a three-point scale (too short, OK, too long).

FINDINGS

This study found no difference in antibacterial efficacy attributable to formulation or format for the two 'standard' ABHR formulations, as assessed by EN 1500. When measured objectively, the EtOH-based formulations dried more rapidly than the IPA-based formulations, and for both formulations, gels took longer to dry than other formats. User perception of drying time broadly agreed with objective measurement.

CONCLUSION

Given that there was no difference in efficacy and only moderate difference in drying time, it is proposed that ABHR in liquid, foam or gel format may be appropriate, provided that the specific product passes the required efficacy and safety standards.