The use of a radiolabelled saccharin solution to monitor the effect of the preservatives thiomersal, benzalkonium chloride and EDTA on human nasal clearance.

The effect of thiomersal, benzalkonium chloride and ethylenediaminetetraacetic acid (EDTA) on the nasal mucociliary clearance of healthy volunteers has been investigated using a modified saccharin test and gamma scintigraphy concomitantly. A significant correlation was found between the two techniques. Using each subject as his/her own control, none of the preservatives significantly altered the rate of clearance or proportion cleared from the nasal cavity after the administration of a single dose. This result is at variance with some in-vitro findings.