The effect of benzalkonium chloride on rabbit nasal mucosa in vivo: an electron microscopy study

Adverse Outcome Pathway for Antimicrobial Quaternary Ammonium Compounds

Quaternary ammonium compounds (QACs) or quats are a large class of antimicrobial chemicals used in households and institutions as sanitizers and disinfectants. These chemicals are utilized as food processing sanitizers, algicides, in the process of water treatment, and preservatives in cosmetics. The aim of this study was to determine an Adverse Outcome Pathway (AOP) whereby two widely used QACs, alkyl dimethyl benzyl ammonium chloride (ADBAC) and didecyl dimethyl ammonium chloride (DDAC), may result in respiratory tract and gastrointestinal tract effects. When inhaled or ingested, these QACs are incorporated into the epithelial cell membrane at the point of contact. With sufficient dosage, the epithelial membrane is disrupted, reducing its fluidity, and releasing cellular contents. Further, ADBAC and DDAC might disrupt mitochondrial functions leading to decreased ATP production. Both events might lead to cell death, either attributed to direct lysis, necrosis, or apoptosis. Pro-inflammatory mediators are recruited to the tissue, inducing inflammation, edema, and excess mucus production. The primary tissue-level adverse outcome is epithelial degeneration and dysplasia. Most important, no apparent metabolism or distribution is involved in QAC action. Based upon this knowledge, it is suggested to replace default Uncertainty Factors for risk assessments with a set of Data Derived Extrapolation Factors.

In Vitro Ciliotoxicity and Cytotoxicity Testing of Repeated Chronic Exposure to Topical Nasal Formulations for Safety Studies

Certain active drugs and excipients of nasal formulations may impair ciliary function and mucociliary clearance. The ciliary beat frequency (CBF) is a key parameter for determining mucociliary clearance rate, and in vitro assessments of CBF have proven to be accurate and reproducible. Since topical nasal formulations are applied with repeated doses, it is essential to elucidate their chronic, as opposed to acute, effect on mucociliary clearance and nasal mucosa. The aim of this study was to assess for the first time the ciliotoxicity and cytotoxicity of nasal sprays intended for chronic treatment (with repeated doses) using a previously designed set-up for CBF measurements. For 2 weeks, the 3D nasal MucilAir™ in vitro models were treated daily with undiluted or clinically relevant doses of mometasone nasal spray, placebo nasal spray, culture medium, or they were untreated. We demonstrated a dose-dependent and time-dependent (cumulative) effect of the nasal sprays on ciliary activity and cytotoxicity using CBF measurements and ultrastructural analysis, respectively. Our results indicate that repeated administration of clinically relevant doses of mometasone nasal spray is safe for in vivo use, which is in good agreement with a previous clinical study. Overall, our study suggests that such in vitro assays have great potential for topical nasal drug screening.

Nasal Toxicity of Benzalkonium Chloride

Background

Benzalkonium chloride (BAC) is added to nasal preparations to prevent microbial contamination. Adverse effects of BAC on human nasal mucosa should be evaluated.

Methods

The ciliotoxicity of BAC was assessed in isolated human nasal epithelia from 15 donors. The effects of nasal BAC 0.05% (4 X 200 μL/day for 8 days) on nasal saccharin transport time, inflammatory cells and cytokine levels in nasal secretions, and nasal symptom scores were assessed in a randomized, double-blind crossover trial in 16 healthy volunteers.

Results

In vitro, BAC was ciliotoxic (p < 0.0001). In vivo, BAC did not alter saccharin transport time in healthy individuals (p > 0.8). No BAC-associated proinflammatory effects were observed. The staining index for myeloperoxidase was 4.8% in the placebo period and 6.3% (p = 0.42) in the BAC period. Also, nasal secretion levels of cytokines and the neuropeptide substance P revealed no BAC-associated differences. Concentrations for interleukin (IL)-6 in the placebo period were 41.5 pg/mL (0.9–91.7 pg/mL) and in the BAC period were 17.6 pg/mL (3.2–65.9 pg/mL; p = 0.46), and concentrations for substance P were 119 pg/mL (58–293 pg/mL) and 131 pg/mL (80–330 pg/mL; p = 0.31), respectively. Immediately after application, BAC caused nasal irritation (p = 0.001), a burning sensation (p = 0.0003), and hypersecretion (p = 0.006). Moreover, BAC caused a persistent sensation of nasal irritation (p < 0.01).

Conclusion

BAC in concentrations used in nasal preparations is ciliotoxic. In healthy individuals, the ciliotoxic effect of BAC is neutralized, probably by components of nasal secretions. No BAC-related proinflammatory effects have been observed. At higher doses than normally used therapeutically, BAC caused significant nasal irritation. (American Journal of Rhinology 18, 291–299, 2004)

Risk assessment of benzalkonium chloride in cosmetic products

A risk assessment of benzalkonium chloride (BAC) was conducted based upon its toxicological profile and exposure evaluation. Since 1935, BAC has been used in a wide variety of products such as disinfectants, preservatives, and sanitizers. It is well-established that BAC is not genotoxic nor does it display tumorigenic potential, but safety concerns have been raised in local usage such as for ocular and intranasal applications. The Foundation of Korea Cosmetic Industry Institute (KCII) reported that in a hair conditioner manufactured as a cosmetic or personal product in South Korea, BAC was present at concentrations of 0.5-2%. The systemic exposure dosage (SED) was determined using the above in-use concentrations and a risk assessment analysis was conducted. The Margin of Safety (MOS) values for hair conditioners were calculated to be between 621 and 2,483. The risk of certain personal and cosmetic products was also assessed based upon assumptions that BAC was present at the maximal level of regulation in South Korea and that the maximal amount was used. The MOS values for the body lotion were all above 100, regardless of the application site. Collectively, data indicate that there are no safety concerns regarding use of products that contain BAC under the current concentration restrictions, even when utilized at maximal permitted levels. However, a chronic dermal toxicity study on BAC and comprehensive dermal absorption evaluation needs to be conducted to provide a more accurate prediction of the potential health risks to humans.

Pulmonary Toxicity of Benzalkonium Chloride

The available toxicity data of benzalkonium chloride (BKC) clearly shows that it is toxic; however, the weight of evidence favors the view that at doses encountered in nasally and orally inhaled pharmaceutical preparations it is well tolerated. The adverse toxicological data predominantly come from in vitro and animal studies in which doses and exposure periods employed were excessive in relation to the clinical doses and their posology and, therefore, not directly applicable to the clinic. The conflict between the in vitro and animal data and the clinical experience can be reconciled by understanding some of the physicochemical properties of BKC, the nasal and respiratory tract microenvironments, the doses used, and the posology.

Assessment of ocular discomfort caused by 5 shampoos using the Slug Mucosal Irritation test

Assessment of ocular discomfort caused by veterinary care products is less legitimately regulated than that caused by human care products. The Slug Mucosal Irritation (SMI) assay was adapted to evaluate canine hygiene shampoos to predict ocular discomfort. Experiments were performed using four commercial canine shampoos, a baby care product, and two controls (ArtTear® and BAC1%). Groups of 3 slugs were tested with 5% dilution of the 7 test substances. The negative control (ArtTear®) was the best tolerated. The baby care product Mixa bébé as well as Douxo Entretien Démêlant and Phlox Shampooing Entretien were classified to cause mild ocular discomfort. Together with the positive control (BAC 1%), Shampooing Physiologique Virbac and Physiovet Shampooing were considered to cause severe ocular discomfort. Different intensities of ocular discomfort were measured for veterinary care products. The SMI model was considered as a reproducible and adaptable evaluation method for screening veterinary care products causing ocular discomfort.

Rhinitis medicamentosa: Electron microscopic changes of human nasal mucosa

OBJECTIVE: Prolonged application of nasal vasoconstrictors causes rhinitis medicamentosa (RM). Nasal obstruction is induced by rebound swelling when the decongestive effect has disappeared. The aim of this study was to demonstrate ultrastructural changes in RM.

STUDY DESIGN AND SETTING: Tissue samples of inferior turbinates from 22 patients with RM and 10 patients without rhinitis were taken during nasal surgery. Ultrathin sections were investigated by using a transmission electron microscope (TEM).

RESULTS: The TEM findings revealed severe epithelial damages such as loss of ciliated cells. In the subepithelial region, the vascular endothelium showed gaps and ruptures of basal lamina.

CONCLUSION: RM is a drug-induced damage of human nasal mucosa. Loss and destruction of ciliated epithelial cells are the morphologic correlation of the disturbed mucociliary clearance. In addition, vascular endothelium revealed ultrastructural changes. This could be caused by an increased vascular permeability with consecutive interstitial edema.

SIGNIFICANCE: This study demonstrated new morphological aspects of rhinitis medicamentosa.

© 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.

Effects of benzalkonium chloride on histamine H1 receptor mRNA expression in nasal epithelial cells

OBJECTIVE

To better understand the causes of the exacerbation of rhinitis medicamentosa (RM) induced by oxymetazoline (OMZ) or benzalkonium chloride (BKC), we examined the impact of pretreatment with OMZ or BKC on cultured human nasal epithelial cells. We also examined the effect of mometasone furoate (MF) on the cultured human nasal epithelial cells treated with OMZ or BKC.

METHODS

Cells of the human nasal epithelial cell line HNEpC were treated with OMZ or BKC, and the OMZ- and BKC-induced expression of histamine H1 receptor (H1R) mRNA was assayed using real-time polymerase chain reaction. In some experiments, 1.0×10(-5)M MF was added to the HNEpC cells for 24h before treatment with OMZ or BKC.

RESULTS

Treatment with OMZ slightly increased the expression level of H1R mRNA in HNEpC cells. This enhanced expression was not significantly reduced by pretreatment with MF. In contrast, treatment with BKC remarkably increased the expression level of H1R mRNA in HNEpC cells. In addition, this enhanced expression was significantly reduced by pretreatment with MF.

CONCLUSION

These results suggest that the increased expression of H1R mRNA due to treatment with OMZ or BKC might be one of the factors underlying the exacerbation of symptoms in patients with RM and those complicated with allergic rhinitis. The concomitant use of a nasal steroid might reduce the exacerbation of symptoms caused by BKC, although there remains a risk of developing histamine hypersensitivity from the long-term use of a topical steroid-containing BKC.

High efficiency intranasal drug delivery using Intravail® alkylsaccharide absorption enhancers

A new class of alkylsaccharide transmucosal delivery enhancement agents are described that overcome the principal limitations preventing broad acceptance of intranasal administration for many potential applications in systemic drug delivery, namely, poor transmucosal absorption and damage to the nasal mucosa. This review will describe recent developments in use of these excipients in human clinical trials and preclinical studies along with their chemical and pharmacological properties and explore commercial implications of the use of these excipients in introduction of new intranasal formulations of peptidic and nonpeptidic drugs.

The Slug Mucosal Irritation (SMI) assay: a tool for the evaluation of nasal discomfort

In this research project, the Slug Mucosal Irritation (SMI) assay was applied to predict nasal discomfort, investigating the correlation between responses in slugs and humans. Several SMI experiments and a Human Nose Irritation Test (HNIT) were performed with five NaCl solutions (0.4%, 1.3%, 2.6%, 5.4% and 10.4%) and two benzalkonium chloride solutions (BAC 0.02% and BAC 0.05%). In the HNIT, subjective evaluation of clinical discomfort was performed by 24 participants at several time points. Analyzes reveal that (1) a significant positive association existed between immediate stinging reaction reported by the participants and the mean total mucus production of the slugs (Spearman's Rank correlation=0.963, p<0.001); (2) NaCl 0.4% was best tolerated in both tests; (3) a concentration-response effect was observed for NaCl and BAC solutions; (4) NaCl 10.4% induced the highest mucus production in the slugs and received higher sting scores for immediate discomfort in the HNIT; (5) stinging sensations decreased rapidly in time and (6) based on these results a new classification prediction model for nasal applications was established. In conclusion, the SMI assay is a promising evaluation method for clinical nasal discomfort. Screening (prototype) formulations with this assay allows formula optimization prior to a clinical trial.

Anticancer drug vinblastine sulphate induces transient morphological changes on the olfactory mucosa of the rabbit

Vinblastine sulphate (VBS) is an anticancer drug that acts by disrupting microtubule dynamics of highly mitotic tissue cells. The consequences of VBS on the olfactory mucosa (OM), a tissue with high mitotic numbers, are not clearly understood. We used qualitative and quantitative methods to determine the structural changes that may be produced on the rabbit OM by VBS. Following a single dose (0.31 mg/kg) of this drug, the structure of the mucosa was greatly altered on the first 3-5 days. The alteration was characterized by disarrangement of the normal layering of nuclei of the epithelia, degeneration of axonal bundles, occurrence of blood vessels within the bundles, localized death of cells of Bowman's glands and glandular degeneration. Surprisingly on or after day 7 and progressively to day 15 post-exposure, the OM was observed to regenerate and acquire normal morphology, and the vessels disappeared from the bundles. Relative to control values, bundle diameters, olfactory cell densities and cilia numbers decreased to as low as 53.1, 75.2 and 71.4%, respectively, on day 5. Volume density for the bundles, which was 28.6% in controls, decreased to a lowest value of 16.8% on day 5. In contrast, the volume density for the blood vessels was significantly lower in controls (19.9%) than in treated animals at day 2 (25.8%), day 3 (34.3%) and day 5 (31.5%). These findings suggest that the changes induced on the rabbit OM by VBS are transient and that regenerative recovery leads to the restoration of the normal structure of the mucosa.

Topical glucocorticoid reduces the topical decongestant-induced histologic changes in an animal model nasal mucosa

OBJECTIVES/HYPOTHESIS

To investigate the histologic consequences of simultaneous nasal glucocorticosteroid and xylometazoline HCl administration in the rabbit nasal mucosa.

STUDY DESIGN

Prospective randomized study.

METHODS

Twenty New Zealand male rabbits were randomly placed into three groups: group I, control (n = 6); group II, xylometazoline HCl (n = 8); or group III, xylometazoline HCl-fluticasone furoate (n = 6). Group I received no treatment. Groups II and III received two intranasal puffs of xylometazoline HCl 0.5 mg/mL twice daily or two puffs of xylometazoline HCl 0.5 mg/mL twice daily plus one puff of 27.5 μg fluticasone furoate twice daily to each nostril (110 μg), respectively. At the end of 3 weeks, the rabbits were sacrificed. The mucosa of the nasal cavities was excised. Specimen sections (5 μm) were stained with hematoxylin and eosin, mucicarmine, and Gomori one-step trichrome and were examined under a light microscope. The presence of edema, congestion, inflammatory cell infiltration, nasociliary loss, epithelial and nerve-ending degeneration, and goblet cell increase were evaluated semiquantitatively (grades 0-3).

RESULTS

Statistically significant differences were detected between groups II and III in terms of edema, congestion, inflammatory cell infiltration, nasociliary loss, and epithelial degeneration (P = .006, P = .049, P = .015, P = .014, and P = .049, respectively). Nerve-ending degeneration, goblet cell increase, and quantitative goblet and neutrophil cell counts did not yield statistically significant differences between groups II and III (P = .137, P = .580, P = .770, and P = .616, respectively).

CONCLUSIONS

The combined simultaneous intranasal administration of xylometazoline HCl and fluticasone furoate appears to be beneficial in minimizing the long-term usage-associated congestion, edema, inflammatory cell infiltration, epithelial degeneration, and nasociliary loss in the rabbit model nasal mucosa.

New aspects of the Slug Mucosal Irritation assay: predicting nasal stinging, itching and burning sensations

Stinging, itching and/or burning (SIB) sensations cannot be detected by animal tests or in vitro models. In the past, the Slug Mucosal Irritation (SMI) assay demonstrated a relation between an increased mucus production in slugs and an elevated incidence of SIB sensations in humans. A new 1-day SMI test procedure was developed focusing on the prediction of these short-term sensations. The objective of this study was to verify whether this new procedure is capable predicting mucosal tolerance of several marketed nasal formulations using the slug Arion lusitanicus. Irritation and tissue damage were quantified with a 5-day repeated exposure study by means of the mucus produced and proteins and enzymes released. The new protocol predicted SIB sensations by means of mucus production. The effects of six liquid nasal formulations were tested with both protocols, while five physiologic saline solutions were only tested with the new protocol to optimize it. None of the tested liquid nasal formulations resulted in tissue damage; however, exposure to the different formulations had a clear effect on the mucus production of the slugs and moderate discomfort was observed in some cases. These effects were due to the active ingredient, the presence of benzalkonium chloride as a preservative or the hyperosmolality of the formulation. For the most part results agreed with clinical data found in literature. It was concluded that the SMI assay, and the new 1-day protocol in particular, is a good tool to predict nasal clinical discomfort.

In vitro modulation of preservative toxicity: high molecular weight hyaluronan decreases apoptosis and oxidative stress induced by benzalkonium chloride

OBJECTIVE

Benzalkonium chloride (BAK) is one of the most often used preservative in pharmaceutical products and it is known to induce toxic effects. Hyaluronan (HA), a linear biopolymer, is involved in several biological processes. The aim of this work is to in vitro investigate if HA is able to decrease BAK toxicity.

METHODS

Two human epithelial cell lines were treated with different incubation time protocol with BAK and three different molecular weights HA (HA 20k Da, HA 100 kDa and HA 1000 kDa, 0.2%, w/v). Flow cytometry, fluorescence microscopy, microplate cytofluorometry and confocal microscopy were performed to evaluate expression of CD44 receptor, cell viability, oxidative stress, mitochondrial mass, chromatin condensation, plasma-membrane permeability, DNA fragmentation and cytoskeleton morphology.

RESULTS

The three HAs studied induce neither oxidative stress nor apoptosis. HA 1000 kDa significantly decreases oxidative stress, apoptosis and necrosis induced by BAK. Experiments with HA 20 kDa or HA 100 kDa did not show the same effects. For instance, the more molecular weight decreases, the more protection decreases. Moreover, we suggest that HA interacts with cell plasma-membrane and inhibits cell death receptors.

CONCLUSION

High molecular weight HA (1000 kDa, 0.2%) is an effective protective agent against BAK.

Formulation considerations of intranasal corticosteroids for the treatment of allergic rhinitis

OBJECTIVE

To examine how various aspects of an intranasal corticosteroid (INS) formulation may influence the efficacy, tolerability, and patient preference and adherence to INS therapy.

DATA SOURCES

A PubMed search of the literature was conducted for studies on allergic rhinitis published between January 1977 and January 2006 using the keywords intranasal corticosteroid, preservatives, benzalkonium chloride, and tonicity.

STUDY SELECTION

Prospective studies, retrospective studies, and case reports were selected for inclusion in this review.

RESULTS

Currently available INSs are effective first-line treatments for allergic rhinitis. Differences in patient preference for a particular INS are largely attributable to sensory attributes of the nasal spray, which arise from characteristics of the formulation. Additives and preservatives can cause tolerability issues by irritating the mucosal membranes and causing nasal drying, or they can confer an unpleasant odor or taste to an INS formulation. The relative osmotic pressure, or tonicity, of an INS can modulate nasal absorption and retention, thereby potentially influencing the clinical efficacy. Characteristics such as delivery device and spray volume can affect a patient's perception and experience with a particular INS. Newer INSs, such as ciclesonide, are in development for the treatment of allergic rhinitis, and consideration of the formulation characteristics of these agents is an important part of the development process.

CONCLUSIONS

INSs are an effective treatment option for patients with allergic rhinitis; however, there is room for formulation improvement. Optimization of formulation may increase the efficacy, tolerability, and patient preference and adherence to INSs.

Effect of preservatives on ciliary beat frequency in human nasal epithelial cell culture: single versus multiple exposure

As preservatives may impair mucociliary clearance, we wanted to systematically study their time-dependent effect on the ciliary beat frequency (CBF) in human nasal epithelial cells (HNEC). CBF was determined using a high-speed digital imaging method. Five preservatives were selected including benzalkonium chloride, phenylethyl alcohol, methylparaben, propylparaben and chlorbutol. We were interested in the effect of these preservatives on CBF after single and repetitive exposure. Methylparaben (0.0033%), propylparaben (0.0017%) and chlorbutol (0.005%) did not impair CBF, neither after a single short-term exposure period, nor after a single long-term exposure period. Long-term exposure to benzalkonium chloride (0.001%), phenylethyl alcohol (0.125%) and a combination of methyl- and propylparaben (0.0033 and 0.0017%) significantly decreased CBF. After a short-term exposure period, CBF recovered for phenylethyl alcohol and the combination of methyl- and propylparaben. Benzalkonium chloride decreased CBF non-reversibly. For two compounds, the effect on CBF was evaluated after repetitive exposure during 15min for 5 consecutive days. Benzalkonium chloride resulted in ciliostasis for all concentrations tested after 5 days. Phenylethyl alcohol revealed a concentration-dependent effect on CBF, but no ciliostasis was observed. In conclusion, methylparaben, propylparaben and chlorbutol can be considered as cilio-friendly. Repetitive exposure revealed a cumulative effect on CBF for benzalkonium chloride and phenylethyl alcohol.

Ultrastrukturelle Veränderungen der Nasenschleimhaut des Menschen nach Abusus von topischen α-Sympathomimetika

BACKGROUND

Long-term abuse of decongestive nasal drops causes rhinitis medicamentosa due to cytotoxic and ciliary-toxic effects. Nasal obstruction is caused by rebound swelling when the decongestive effect has disappeared. The patient starts using nasal drops more frequently as a result of tachyphylaxis.

PATIENTS AND METHODS

Tissue samples from human inferior turbinates from 22 patients who had overused decongestive nose drops were taken during nasal surgery and preserved in phosphate-buffered paraformaldehyde or glutaraldehyde. Ultrathin sections were cut. The samples were dehydrated and embedded in Araldit. The findings were photo-documented using a light- and transmission electron microscope. Biopsies from ten patients without chronic inflammation of the nasal mucosa were used as controls.

RESULTS

The electron microscopic investigations revealed epithelium showing severe damage corresponding to regions with hyperplastic and metaplastic changes. Loss of ciliated cells was observed. Under a thick basal membrane, ultrastructural changes to the endothelial lining, such as openings and rupture of the basal lamina, were detected. Prominent endothelial cells were conspicuous.

CONCLUSIONS

Rhinitis medicamentosa is a drug-induced injury to human nasal mucosa associated with the prolonged abuse of topical nasal decongestants. Loss and destruction of ciliated epithelial cells are the morphological correlation to the disturbance of mucociliary clearance. Endothelial cells of capillaries, in particular, revealed ultrastructural changes indicative of increased permeability with consecutive interstitial edema.

Immediate effect of benzalkonium chloride in decongestant nasal spray on the human nasal mucosal temperature

Benzalkonium chloride is a preservative commonly used in nasal decongestant sprays. It has been suggested that benzalkonium chloride may be harmful to the nasal mucosa. Decongestion with the vasoconstrictor xylometazoline containing benzalkonium chloride has been shown to cause a significant reduction of the nasal mucosal temperature. The purpose of the present study was to determine the short-term influence of xylometazoline nasal spray with and without benzalkonium chloride on the nasal mucosal temperature. Healthy volunteers (30) were included in the study. Fifteen volunteers received xylometazoline nasal spray (1.0 mg/mL) containing benzalkonium chloride (0.1 mg/mL) and 15 age-matched subjects, received xylometazoline nasal spray without benzalkonium chloride. Using a miniaturized thermocouple the septal mucosal temperature was continuously measured at defined intranasal detection sites before and after application of the nasal spray. The mucosal temperature values did not significantly differ between the group receiving xylometazoline containing benzalkonium chloride and the group receiving xylometazoline spray without benzalkonium chloride before and after decongestion (P > 0.05). In both study groups septal mucosal temperatures significantly decreased after decongestion (P < 0.05) because of a reduction of the nasal mucosal blood flow following vasoconstriction. This study indicates that benzalkonium chloride itself does not seem to influence nasal blood flow and nasal mucosal temperature in topical nasal decongestants.