In vitro effects of preservatives in nasal sprays on human epithelial cells

Background: The preservatives benzalkonium chloride and potassium sorbate are widely used in nasal drops and sprays. Recently, side effects resulting from mucosal damage caused by benzalkonium chloride and potassium sorbate were reported. Methods: We investigated the toxicity of benzalkonium chloride and potassium sorbate on human nasal epithelial cells in vitro. Using primary human nasal epithelial cells, different concentrations of benzalkonium chloride, potassium sorbate, or phosphate-buffered saline (PBS; control group) solutions were cocultured with nasal epithelial cells for 15 minutes. Then, the viability of the cells and the cell morphology were assessed. Results: Nasal epithelial cells were more severely damaged with use of clinical preparations or higher concentrations of benzalkonium chloride than in the control group. In addition, nasal epithelial cell membrane lysis was seen on electronic microscopy in the benzalkonium chloride groups. In contrast, there zoos no significant cell damage seen in the potassium sorbate groups compared with the control group, even with higher concentrations than clinically used. Conclusion: Potassium sorbate appears to be a relatively safer preservative than benzalkonium chloride for use in nasal sprays and drops in vitro study.