Expansile properties of otowicks: an in vitro study.

OBJECTIVE

To determine the expansile and absorptive properties of the expandable ear wick when tested with commonly prescribed ear drop preparations.

DESIGN

This in vitro study assessed wick expansion and absorption of drops when different ear drop preparations were applied. Nine commonly used ear drop preparations were tested (Gentisone HC, Sofradex, Otomize, Betnesol, Exocin, Canesten, Locorten-Vioform, EarCalm and ichthammol glycerin) with a standard expandable ear wick.

MAIN OUTCOME MEASURES

Weight, length and width of otowick following exposure to ear drops.

RESULTS

There was a marked difference in the absorption and expansion of the otowick when different drops were used. This corresponded to the aqueous or oil base of each preparation. All aqueous ear drop preparations (i.e. Gentisone HC, Sofradex, Otomize, Betnesol, Exocin and EarCalm) produced similar rates of absorption into, and expansion of, the otowick. The oil-based ear drop preparations (i.e. Canesten, Locorten-Vioform and ichthammol glycerin) failed to expand the wick and showed poor rates of absorption into the wick.

CONCLUSION

Expandable ear wicks should only be used in conjunction with aqueous ear drops. When using expandable otowicks as an adjunct to treating fungal otitis externa, acetic acid ear drops should be prescribed, as all other anti-fungal drops are oil-based.