Study of post-opening stability of active ingredients in hand sanitizers

Hand disinfection plays an important role in infection control. Currently, hand sanitizers containing ethanol and chlorhexidine gluconate as active ingredients are widely used. Most of hand sanitizers have a defined expiration date for use. However, there was no rule about the expiration date after opening defined with the evidence. Therefore, we examined the fluctuation of active ingredients and disinfection effect after opening the bottle.

Twelve hand sanitizers from 44 to 921 days after opening set in different places in the hospital were examined and unopened hand sanitizer used as a control. Chlorhexidine gluconate and ethanol of each samples were measured by high performance liquid chromatography and gas chromatography, respectively. The correlation between the concentration of each ingredient obtained and the number of days after opening, bottle weight, storage temperature and humidity was analyzed. A time-kill test based on ASTM E2315-03 was performed to confirm the actual disinfection effect.

It was observed that active ingredients had not been decreased up to 921 days after opening and were not affected by storage conditions after opening. In addition, a decrease of disinfection effect was not observed in any sample.

We found that hand sanitizers do not need to be discard after a number of days have passed because the active ingredients are retained even after opening in it.