Background: Benzalkonium chloride (BAC) is a quaternary ammonium compound (QAC) with a C 8 to C 18 chain length of alkyl groups. Since BAC exerts toxic effects on microorganisms, it has been used as an effective germicide and preservative, mostly in cosmetic industry and medicine. However, the toxic potential of BAC may be hazardous to humans, due to the common use of preparations containing BAC as a preservative. Material and Methods: To assess the possible toxic effects of BAC, two-stage experiments were performed on female Wistar rats. At first, LC 50 after a single exposure to BAC aerosol was determined. Then, the animals were exposed to BAC aerosol at 30 mg/m 3 for 6 h, and for 3 days (6 h/day). The controls were unexposed rats. Directly after BAC exposure and 18 h afterwards,, BALF concentrations were measured of total protein, Clara cell protein, matrix metalloproteinase-9 (MMP-9), hyaluronic acid (HA), immunoglobulin E (IgE) and cytokines (TF-α, IL-6 and MIP-20), lactate dehydrogenase (LDH) and GSH-S-transferase (GST). Results: The LC 50 value for exposed rats was ca. 53 mg BAC in m 3 air for 4 h. All the rats survived single and repeated inhalation exposure to 30 mg/m 3 BAC. After single and repeated exposure, lung weight, total protein, HA and LDH activity in BALF of exposed rats were higher than in controls while CC16 levels were decreased. A significantly higher BALF concentration of IL-6 and IgE was noted in animals exposed to single and repeated doses. BALF concentrations of MMP-9, TNF-α, and MIP-2 in exposed rats were similar to those in control animals. Conclusion: BAC may be classified to class I acute inhalation toxicity. It showed a strong inflammatory and irritant activity on the lungs after 6h inhalation and stimulated dynamic patterns of IL-6 and IgE production and protein infiltration from blood vessels to BALF. Continued exposure resulted in cellular destruction, a statistically significant increase in LDH activity and a continuous decrease in CC16 concentration in BALF.

Background: Benzalkonium chloride (BAC) is a quaternary ammonium compound (QAC) toxic to microorganisms. Inhalation is one of the major possible routes of human exposure to BAC. Materials and Methods: Experiments were performed on female Wistar rats. The rats were exposed to aerosol of BAC water solution at the target concentration of 0 (control group) and 35 mg/m 3 for 5 days (6 h/day) and, after a 2-week interval, the animals were challenged (day 21 ) with BAC aerosol at the target concentration of 0 (control group) and 35 mg/m 3 for 6 h. Results: Compared to the controls, the animals exposed to BAC aerosol were characterized by lower food intake and their body weight was significantly smaller. As regards BAC-exposed group, a significant increase was noted in relative lung mass, total protein concentration, and MIP-2 in BALF both directly after the termination of the exposure and 18 h afterwards. Significantly higher IL-6 and IgE concentrations in BALF and a decrease in the CC16 concentration in BALF were found in the exposed group immediately after the exposure. The leukocyte count in BALF was significantly higher in the animals exposed to BAC aerosol compared to the controls. In the lungs of rats exposed to BAC the following effects were observed: minimal perivascular, interstitial edema, focal aggregates of alveolar macrophages, interstitial mononuclear cell infiltrations, thickened alveolar septa and marginal lipoproteinosis. Conclusion: Inhalation of BAC induced a strong inflammatory response and a damage to the blood-air barrier. Reduced concentrations of CC16, which is an immunosuppressive and anti-inflammatory protein, in combination with increased IgE concentrations in BALF may be indicative of the immuno-inflammatory response in the animals exposed to BAC aerosol by inhalation. Histopathological examinations of tissue samples from the BAC-exposed rats revealed a number of pathological changes found only in the lungs.

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Background: Benzalkonium chloride (BAC) is a quaternary ammonium compound (QAC) with a C 8 to C 18 chain length of alkyl groups. Since BAC exerts toxic effects on microorganisms, it has been used as an effective germicide and preservative, mostly in cosmetic industry and medicine. However, the toxic potential of BAC may be hazardous to humans, due to the common use of preparations containing BAC as a preservative. Material and Methods: To assess the possible toxic effects of BAC, two-stage experiments were performed on female Wistar rats. At first, LC 50 after a single exposure to BAC aerosol was determined. Then, the animals were exposed to BAC aerosol at 30 mg/m 3 for 6 h, and for 3 days (6 h/day). The controls were unexposed rats. Directly after BAC exposure and 18 h afterwards,, BALF concentrations were measured of total protein, Clara cell protein, matrix metalloproteinase-9 (MMP-9), hyaluronic acid (HA), immunoglobulin E (IgE) and cytokines (TF-α, IL-6 and MIP-20), lactate dehydrogenase (LDH) and GSH-S-transferase (GST). Results: The LC 50 value for exposed rats was ca. 53 mg BAC in m 3 air for 4 h. All the rats survived single and repeated inhalation exposure to 30 mg/m 3 BAC. After single and repeated exposure, lung weight, total protein, HA and LDH activity in BALF of exposed rats were higher than in controls while CC16 levels were decreased. A significantly higher BALF concentration of IL-6 and IgE was noted in animals exposed to single and repeated doses. BALF concentrations of MMP-9, TNF-α, and MIP-2 in exposed rats were similar to those in control animals. Conclusion: BAC may be classified to class I acute inhalation toxicity. It showed a strong inflammatory and irritant activity on the lungs after 6h inhalation and stimulated dynamic patterns of IL-6 and IgE production and protein infiltration from blood vessels to BALF. Continued exposure resulted in cellular destruction, a statistically significant increase in LDH activity and a continuous decrease in CC16 concentration in BALF.