The effects of topical nasal steroids on rat respiratory mucosa in vivo, with special reference to benzalkonium chloride

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.

Intranasal drug delivery: opportunities and toxicologic challenges during drug development

Over the past 10 years, the interest in intranasal drug delivery in pharmaceutical R&D has increased. This review article summarises information on intranasal administration for local and systemic delivery, as well as for CNS indications. Nasal delivery offers many advantages over standard systemic delivery systems, such as its non-invasive character, a fast onset of action and in many cases reduced side effects due to a more targeted delivery. There are still formulation limitations and toxicological aspects to be optimised. Intranasal drug delivery in the field of drug development is an interesting delivery route for the treatment of neurological disorders. Systemic approaches often fail to efficiently supply the CNS with drugs. This review paper describes the anatomical, histological and physiological basis and summarises currently approved drugs for administration via intranasal delivery. Further, the review focuses on toxicological considerations of intranasally applied compounds and discusses formulation aspects that need to be considered for drug development.

Evaluation of Protective and Therapeutic Effects of Dexpanthenol on Nasal Decongestants and Preservatives: Results of Cytotoxic Studies in Vitro

Background

More than 600 million units of nasal decongestants are sold worldwide annually. The cytotoxic and ciliary toxic potential of decongestants, as well as the preservatives of these products, in particular benzalkonium chloride (BKC), is well established. Recently, a beneficial effect of dexpanthenol on the tolerability of the ά-sympathomimetic xylometazoline and BKC has been described; however, it was unclear if this effect, resulting in significantly higher cell counts in a cytotoxicity study and an increase in ciliary beat frequency in a ciliary toxicity study was of protective or therapeutic nature. The objective of this study was (a) to evaluate whether dexpanthenol would be a useful additive to nasal decongestants to counter the cytotoxic and ciliary toxic effects of the active ingredient and the preservative and (b) to find out whether this beneficial effect is of protective or therapeutic nature.

Methods

Systematic cytotoxic in vitro tests were performed. After exposure to xylometazoline (0.1%), the effect of dexpanthenol (5%) and BKC (0.01%) was determined by placebo-controlled assessment of cell growth in a human amniotic cell line.

Results

Dexpanthenol significantly reduces the toxic effects of xylometazoline regarding cell growth (p < 0.001) when applied in advance. When BKC is eliminated from the nasal sprays, a further significant increase of cell growth was found (p < 0.001). When dexpanthenol is therapeutically applied after xylometazoline, effects on cell growth are only one-half of those of the protective approach.

Conclusion

The additive application of dexpanthenol (5%) given before nasal decongestants or preserved nasal sprays is able to improve the tolerability of these substances and to counteract the toxic effects. (American Journal of Rhinology 18, 315–320, 2004)

Nasoseptal Perforation: from Etiology to Treatment

PURPOSE OF REVIEW

Nasal septum perforation (NSP) is a communication between the two nasal cavities. This review contributes to the better knowledge of NSP causes, diagnosis, and treatment.

RECENT FINDINGS

NSP prevalence is about 1%. Clinical presentation may range from absence of symptoms to the presence of bothersome sinonasal symptoms. NSP is more frequently caused by trauma or post-surgery, inflammatory diseases, and abuse substances. Conservative management (nasal irrigation, topical use of antibiotic or lubricant ointments, or placement of prosthesis) is considered the first-line treatment. Symptomatic NSP not improving with local therapies usually requires surgical approach. Selection of the technique for the endoscopic septal repair depends on perforation characteristics and surgeon experience. When NSP is diagnosed, its cause has to be promptly determined. Most of them can be controlled with conservative measures. Surgical/endoscopic approaches are usually needed in refractory cases, and new repair techniques have to be considered.

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.

Xylometazoline nasal drops induced anaphylaxis: An atypical perioperative complication

Xylometazoline nasal drops used for nasal decongestion can have side-effect in the form of palpitation, hypertension, headache, and tremors. Anaphylaxis to xylometazoline nasal drops is a relatively unrecognized complication. We encountered a patient posted for tonsillectomy who developed serious anaphylaxis upon administration of a commercially available preparation of xylometazoline nasal drops and required aggressive management for stabilization. Further evaluation and literature search indicated toward the preservative (benzylalkonium chloride) as the cause of this adverse event.

Use of Mometasone Furoate Aqueous Nasal Spray in the Treatment of Rhinitis Medicamentosa: An Experimental Study

OBJECTIVE: We aimed to investigate, histopathologic changes in the nasal mucosa of guinea pig's after prolonged administration of oxymetazoline and the development of rhinitis medicamentosa, and the efficacy of mometasone furoate aqueous nasal spray and saline in reversing the ultrastructural changes attributable to rhinitis medicamentosa.

METHODS: In the study, 24 male guinea pigs (500 to 600 gr) were used. Oxymetazolin (0.05%) was sprayed into the nasal cavities of the guinea pigs 3 times daily for 8 weeks. At the end of this period, 6 guinea pigs were killed and examined to make sure that the animals had developed rhinitis medicamentosa. The remaining guinea pigs were randomly divided into 3 groups. In the first group, one spray-puff of 0.05% mometasone furoate aqueous nasal spray (50 μg) was applied twice daily for 14 days. In the second group, saline solution (0.9% NaCl) was applied twice daily for 14 days. No treatment was performed in the third group. At the end of the treatment period, nasal mucosal changes were evaluated by light microscopy and electron microscopy.

RESULTS: After oxymetazolin application for 8 weeks, the main histologic changes were edema, congestion, proliferation of subepithelial glands, and squamous cell metaplasia. After topical mometasone furoate aqueous spray application for 2 weeks, the edema fluid was found to diminish markedly. In the saline and no treatment groups, edema and congestion continued. In these groups of guinea pigs, fibrosis has been seen in the nasal mucosa.

CONCLUSION: We found that mometasone furoate nasal spray was effective against experimentally induced rhinitis medicamentosa in guinea pigs. Mometasone furoate nasal spray may have value in the treatment of patients with rhinitis medicamentosa.

The effects on mucociliary clearance of prednisone associated with bronchial section

OBJECTIVE

Infections have been and remain the major cause of morbidity and mortality after lung transplantation. Because mucociliary clearance plays an important role in human defense mechanisms, the influence of drugs on the mucociliary epithelium of patients undergoing lung transplantation must be examined. Prednisone is the most important corticosteroid used after lung transplantation. The aim of this study was to evaluate the effects of bronchial transection and prednisone therapy on mucociliary clearance.

METHODS

A total of 120 rats were assigned to 4 groups according to surgical procedure or drug therapy: prednisone therapy (1.25 mg/kg/day); bronchial section and anastomosis + prednisone therapy (1.25 mg/kg/day); bronchial section + saline solution (2 ml/day); and saline solution (2 ml/day). After 7, 15, or 30 days, the animals were sacrificed, and the lungs were removed from the thoracic cavity. The in situ mucociliary transport velocity, ciliary beat frequency and in vitro mucus transportability were evaluated.

RESULTS

Animals undergoing bronchial section surgery and anastomosis had a significant decrease in the ciliary beat frequency and mucociliary transport velocity 7 and 15 days after surgery (p<0.001). These parameters were normalized 30 days after the surgical procedure. Prednisone improved mucous transportability in the animals undergoing bronchial section and anastomosis at 15 and 30 days (p<0.05).

CONCLUSION

Bronchial section and anastomosis decrease mucociliary clearance in the early postoperative period. Prednisone therapy improves mucus transportability in animals undergoing bronchial section and anastomosis.

In vitro cytotoxic effects of benzalkonium chloride in corticosteroid injection suspension

BACKGROUND

Some deleterious effects on cartilage and even severe arthropathy have been reported after intra-articular corticosteroid injections. The objective of the present in vitro study was to determine if an injectable corticosteroid suspension is toxic to articular chondrocytes and synovial cells.

METHODS

Human and bovine articular chondrocytes, bovine synovial cells, mouse C3H10T1/2 cells, and human osteosarcoma MG-63 cells were treated for thirty minutes in monolayer or suspension culture with an injectable corticosteroid suspension or its chemical components, including betamethasone sodium phosphate, betamethasone acetate, and benzalkonium chloride (as preservative). Cell viability was determined by means of microscopy or flow cytometry analysis.

RESULTS

In monolayer culture, the betamethasone corticosteroids per se did not cause cell death, whereas benzalkonium chloride caused death of articular chondrocytes. In suspension culture, betamethasone sodium phosphate at dosages of as high as 6 mg/mL did not cause significant death of human or bovine articular chondrocytes (p > 0.05). In contrast, benzalkonium chloride caused a death rate of 10.6% in human articular chondrocytes at a dosage of 10 microg/mL (p < 0.01), 21.0% at a dosage of 13.3 microg/mL (p < 0.01), and 99.3% and 99.4% at dosages of 20 and 200 microg/mL, respectively (p < 0.001 for both). Similarly, benzalkonium chloride caused death of bovine articular chondrocytes, bovine synovial cells, C3H10T1/2 cells, and MG-63 cells in a dose-dependent manner. When treated with a combination of betamethasone sodium phosphate and 200 microg/mL benzalkonium chloride, >99% of human or bovine articular chondrocytes were dead (p < 0.001).

CONCLUSIONS

The injectable corticosteroid suspension caused death in in vitro culture of human and bovine articular chondrocytes as well as bovine synovial cells because of its preservative benzalkonium chloride. The betamethasone corticosteroids per se did not cause significant chondrocyte death under the conditions tested.

In vitro effects of preservatives in nasal sprays on human nasal 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 was 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.

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.

Pathophysiology and progression of nasal septal perforation

OBJECTIVE

To review the prevalence, causes, and treatments of nasal septal perforation (NSP).

DATA SOURCES

A literature search was conducted in MEDLINE to identify peer-reviewed articles related to NSP using the keywords nasal septal perforation and septal perforation for articles published between January 1, 1969, and December 31, 2006, and references cited therein.

STUDY SELECTION

Articles were selected based on their direct applicability to the subject matter.

RESULTS

Causes of NSPs include piercings, exposure to industrial chemicals, illicit drug use, intranasal steroid use, surgical trauma, bilateral cautery, and possibly improper use of nasal applicators. Prevalence is poorly reported. Mechanisms of substance-induced NSP formation are not understood. Progression from epistaxis to ulceration to NSP could not be substantiated by the literature.

CONCLUSION

Depending on the patient, NSP may be viewed as desirable (nose rings), problematic (whistling, congestion), or inconsequential. Understanding the pathogenesis of NSP is important for the practicing physician required to make decisions about whether to recommend surgical correction or medical treatment. Although the etiology of NSP is overwhelmingly iatrogenic, there is an association with a number of medical diseases in addition to use of illicit drugs and/or prescription nasal sprays.

Objective monitoring of nasal patency and nasal physiology in rhinitis

Nasal obstruction can be monitored objectively by measurement of nasal airflow, as evaluated by nasal peak flow, or as airways resistance/conductance as evaluated by rhinomanometry. Peak flow can be measured during inspiration or expiration. Of these measurements, nasal inspiratory peak flow is the best validated technique for home monitoring in clinical trials. The equipment is portable, relatively inexpensive, and simple to use. One disadvantage, however, is that nasal inspiratory peak flow is influenced by lower airway as well as upper airway function. Rhinomanometry is a more sensitive technique that is specific for nasal measurements. The equipment, however, requires an operator, is more expensive, and is not portable. Thus, it is applicable only for clinic visit measures in clinical trials. Measurements require patient cooperation and coordination, and not all can achieve repeatable results. Thus, this objective measure is best suited to laboratory challenge studies involving smaller numbers of selected volunteers. A nonphysiological measure of nasal patency is acoustic rhinometry. This sonic echo technique measures internal nasal luminal volume and the minimum cross-sectional area. The derivation of these measures from the reflected sound waves requires complex mathematical transformation and makes several theoretical assumptions. Despite this, however, such measures correlate well with the nasal physiological measures, and the nasal volume measures have been shown to relate well to results obtained by imaging techniques such as computed tomography scanning or magnetic resonance imaging. Like rhinomanometry, acoustic rhinometry is not suitable for home monitoring and can be applied only to clinic visit measures or for laboratory nasal challenge monitoring. It has advantages in being easy to use, in requiring little patient cooperation, and in providing repeatable results. In addition to nasal obstruction, allergic rhinitis is recognized to be associated with impaired mucociliary clearance and altered nasal responsiveness. Measures exist for the monitoring of these aspects of nasal dysfunction. Although measures of mucociliary clearance are simple to perform, they have a poor record of reproducibility. Their incorporation into clinical trials is thus questionable, although positive outcomes from therapeutic intervention have been reported. Measures of nasal responsiveness are at present largely confined to research studies investigating disease mechanisms in allergic and nonallergic rhinitis. The techniques are insufficiently standardized to be applied to multicenter clinical trials but could be used in limited-center studies to gain insight into the regulatory effects of different therapeutic modalities.

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.

Rhinitis medicamentosa: a review of causes and treatment

Rhinitis medicamentosa (RM) is a drug-induced, nonallergic form of rhinitis that is associated with prolonged use of topical vasoconstrictors, i.e. local decongestants. Symptoms are exacerbated by the preservative benzalkonium chloride (BKC) in the nasal preparations. Nasal stuffiness is caused by rebound swelling of the mucosa when the decongestive effect of the drug has disappeared. To alleviate this symptom, patients gradually start using larger doses of the vasoconstrictor more frequently. In many cases, the patient is unaware of the condition, thus entering a vicious circle of self-treatment. Careful questioning is required during consultation to establish diagnosis. The pathophysiology of the condition is unclear; however, vasodilatation and intravascular edema have both been implicated. Management of RM requires withdrawal of topical decongestants to allow the damaged nasal mucosa to recover, followed by treatment of the underlying nasal disease. Topical corticosteroids such as budesonide and fluticasone propionate should be used to alleviate rebound swelling of the nasal mucosa. Where possible, avoiding exposure to BKC is recommended.

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.

Dexpanthenol—Nasenspray vs. Nasensalbe

BACKGROUND

Recent technical developments in metered pump systems allow the production and use of preservative-free nasal products. The aim of the current study is to compare the tolerability of a preservative-free dexpanthenol (5%) nasal spray with that of the established dexpanthenol (5%) nasal ointment, also without preservatives. The main outcome measure was in vivo mucociliary clearance.

METHOD

Mucociliary clearance was assessed by saccharin migration time in 20 volunteers. Wash-out phases were 7 days and the spray or ointment was always applied 20 min before the saccharin test. The study was designed to test for non-inferiority.

RESULTS

Saccharin migration time was slightly longer after ointment administration, however, these were not significantly different to nasal spray. The saccharin migration time showed a significant correlation with the age of the volunteers. The upper confidence limit of dexpanthenol nasal spray was markedly less than that of the ointment. Therefore, dexpanthenol nasal spray is at least equal to if not better than dexpanthenol nasal ointment.

CONCLUSIONS

Due to its ease of administration, preservative-free dexpanthenol nasal spray offers a valuable therapeutic alternative.

Antimicrobial safety of a preservative-free nasal multiple-dose drug administration system

Recent technical developments in metered-dose pumps allow preservative-free nasal drug application with multiple-dose systems, avoiding the cytotoxic and allergic problems of preservatives. The use of the 3K System as a representative of those systems is demonstrated as microbiologically safe and without risk for the user and for the product during shelf life, under challenge up to 24 weeks, as well as under worst-case conditions with heavy bacterial contamination on the outlet surface. Therefore, the authors assess preservative-free pump systems as the new gold standard for mucosal drug application.

Distribution and disposition of benzalkonium chloride following various routes of administration in rats

Benzalkonium chloride (BZK) is a cationic surfactant used widely as a disinfectant, preservative and sanitizer in hospitals, at home and many public places. The toxicity of BZK is not well established although several human fatalities have been reported over the years. In this study, distribution and disposition of BZK following oral administration (PO) and intravascular (jugular vein (JV), femoral artery (FA), femoral vein (FV) and jugular artery (JA)) administration in rats were investigated along with pathological examinations. Toxic doses of 250 and 15 mg/kg of BZK were used for PO and intravascular administration, respectively. The fatal effects of BZK appeared soon in JV-, FV- or JA-rats, but took hours in PO or FA-rats. No rat receiving BZK via FA survived longer than 1 day. The PO-rats that aspirated BZK into their lungs had some systemic symptoms and higher blood and tissue concentrations of BZK. The blood BZK levels and kinetics were similar among the different routes of intravascular administration, but the lung and kidney levels were higher in JV-rats. Pathological examinations confirmed severe congestion and edema in the lungs and kidneys. These results suggest that (1) the toxic effects of BZK varied depending on the route of administration, (2) the degree of toxicity correlated with peak blood and tissue concentrations in orally dosed rats, (3) different toxicological progressions and manifestations were observed in FA- and JV-dosed rats even though these groups had similar blood concentration profiles, and (4) lung and kidney are reservoirs for BZK and considered to be the target organs of BZK.

Safety review of benzalkonium chloride used as a preservative in intranasal solutions: an overview of conflicting data and opinions

BACKGROUND

For most multiuse aqueous nasal, ophthalmic, and otic products, benzalkonium chloride (BKC) is the preservative of choice. The American College of Toxicology has concluded that BKC can be safely used as an antimicrobial agent at concentrations up to 0.1%. BKC has been in clinical use since 1935 and is contained in a wide variety of prescription and over-the-counter products. However, over the past several years there have been conflicting reports of damage to human nasal epithelia and/or exacerbation of rhinitis medicamentosa associated with intranasal products containing BKC.

OBJECTIVE

We sought to review the published literature and determine whether there is sufficient, clinically significant data that would confirm that intranasal products containing BKC are likely to damage human nasal epithelia or exacerbate rhinitis medicamentosa.

METHODS

A literature search was conducted for in vivo and in vitro studies that evaluated the effects of BKC on human nasal epithelia.

RESULTS

A total of 18 studies (14 in vivo, 4 in vitro) were identified that evaluated short- and long-term exposure of concentrations of BKC in concentrations ranging from 0.00045% to 0.1%. Eight studies, including a 6-month and 1-year long-term treatment study, demonstrated no toxic effects associated with BKC, indicating that BKC was neither harmful to nasal tissue nor prone to exacerbate rhinitis medicamentosa. Furthermore, of the 10 studies that concluded that BKC resulted in degenerative changes in human nasal epithelia (eg, ciliary beat frequency, ciliary morphology, mucociliary clearance, epithelial thinning and/or destruction) or that BKC exacerbates rhinitis medicamentosa, only 2 (it was 2 according to the Results section) of these studies were supported by statistically significant differences between BKC and placebo or active control groups were compared. It is important to note that in both of these studies, the protocol incorporated the use or oxymetazoline in some or all of the subjects. Oxymetazoline is associated with rhinitis medicamentosa.

CONCLUSION

Intranasal products containing the preservative BKC appear to be safe and well tolerated for both long- and short-term clinical use.

Comparisons of two Intranasal Corticosteroid Preparations in Treating Allergic Rhinitis

OBJECTIVES: Intranasal corticosteroid preparations can relieve symptoms of allergic rhinitis. Different aqueous corticosteroid forms have been developed for intranasal use. The objectives of this study were to compare efficacy and safety between fluticasone propionate and budesonide in the treatment for patients with allergic rhinitis.

METHODS: The study was conducted in a prospective and randomized manner; a total of 24 adult patients were enrolled. All patients received MAST allergen test at entry and again at 2 months after treatments. Fourteen patients received fluticasone propionate 200 μg once daily, and 10 patients received budesonide 200 μg twice daily. To investigate the efficacy of fluticasone propionate and budesonide, a subjective scoring system was designed to evaluate the symptom improvement of patients. Adverse events were recorded on a diary card then were analyzed. Mann-Whitney U test and Kruskal-Wallis 1-way analysis of variance were used for statistical analysis.

RESULTS: Analysis on patient-based symptom scores revealed that both fluticasone propionate and budesonide were equally efficacious in improving the symptoms of nasal blockage, sneezing, nasal itching, and watery rhinorrhea. There were no significant side effects reported for both groups during this follow-up period. However, analysis showed that the fluticasone propionate group demonstrated significantly greater improvement in some MAST allergen tests ( Candida, mite, house dust; P < 0.05).

CONCLUSION: Clinically, fluticasone propionate 200 μg once daily was efficacious as budesonide 200 μg twice daily in the relief of allergic rhinitis symptoms. However, fluticasone propionate can achieve greater immunologic improvement. Both preparations showed no evidence of short-term side effects.

Benzalkonium chloride as a preservative in nasal solutions: re-examining the data

Recent studies have suggested that benzalkonium chloride (BKC), an antimicrobial agent used as a preservative in nasal sprays, lacks deleterious effects on the nasal ciliated epithelium. Other data, including recent in vivo findings, suggest that BKC may, in fact, produce adverse clinical effects on human nasal tissue, including the aggravation of rhinitis medicamentosa. Toxic effects have also been reported. In light of the discrepancy between negative results and studies suggesting no safety concerns, we consider the possibility of problems in the design and methodology of some of the studies and in the interpretation of results. Clearly, further research is warranted to clarify the significance of conflicting findings. In the meantime, without conclusive data regarding BKC and the possibility of harmful effects, the use of nasal formulations without BKC might be a reasonable alternative.

The mucosal toxicity of different benzalkonium chloride analogues evaluated with an alternative test using slugs

PURPOSE

The objective of this study was to evaluate the mucosal toxicity of different benzalkonium chloride (BAC) analogues using slugs as the alternative test organism.

METHODS

The effect of different BAC analogues on the mucosal tissue of slugs was determined from the protein, lactate dehydrogenase, and alkaline phosphatase released from the foot mucosa after treatment. Additionally, mucus production and reduction in body weight of the slugs were measured. The eye irritation potency of the molecules was evaluated with the Bovine Corneal Opacity and Permeability (BCOP) assay. The antimicrobial activity of the different BAC analogues was also assessed.

RESULTS

All BAC analogues induced severe damage to the mucosal epithelium of the slugs, and the irritation increased with decreasing alkyl chain length: BAC-C16 < BAC-C14 < BAC-C12 approximately BAC-mix. A similar ranking was obtained with the BCOP assay for eye irritation. The relative order of activities among the three BAC analogues was the same, i.e., BAC-C14 > or = BAC-C16 > BAC-C12. The BAC-C14 exhibited higher activity than the BAC-mix.

CONCLUSIONS

The toxicity and activity of BAC analogues depend on the alkyl chain length. The use of BAC-C14 as a conservative agent in pharmaceutical preparations instead of the BAC-mix should be considered.

Effects of benzalkonium chloride on innate immunity physiology of the human nasal mucosa in vivo

OBJECTIVE

Benzalkonium chloride (BC) is a preservative commonly used in nasal decongestant sprays. It has been suggested that BC may be harmful to the nasal mucosa. The present study, involving healthy volunteers, examines effects of BC on nasal mucosal end-organ functions.

METHODS

Isotonic saline and BC (0.1 mg/mL) were administered acutely to the nasal mucosa using a nasal pool device. Nasal symptoms were determined. Nasal lavage fluid levels of alpha2-macroglobulin and fucose were measured as indices of plasma exudation and glandular secretion, respectively. In addition, BC (0.1 mg/mL) was given as single actuations of 100 microL per nasal cavity three times daily for 10 days. The ability of histamine (0.4 mg/mL) to evoke nasal symptoms and plasma exudation responses was determined before and after the repeated BC administration series.

RESULTS

BC produced immediate nasal smart or pain (P < .05), but tolerance to this response developed by repeated administrations. BC increased nasal mucosal output of fucose (P < .05), whereas nasal lavage fluid levels of alpha2-macroglobulin were unaffected. Histamine produced significant symptoms and mucosal exudation of alpha2-macroglobulin (P values < .01), equally before and after the 10 days of BC exposure.

CONCLUSIONS

BC in dosages commonly used as preservative in nasal decongestant sprays produced short-term glandular secretion and nasal smart or pain. However, 10 days' frequent exposure to BC was not associated with untoward symptomatic effects, nor was a sensitive mucosal variable such as histamine-induced exudative responsiveness affected by this repeated exposure 1 BC.

Long-term use of preservatives on rat nasal respiratory mucosa: effects of benzalkonium chloride and potassium sorbate

OBJECTIVES

The preservatives benzalkonium chloride (BZC) and potassium sorbate (PS) are widely used, not only for nasal drops, but also for eyedrops and cosmetics. However, there have been many case reports that consider lesions such as dermatitis or conjunctivitis to be the results of irritation induced by BZC or PS.

METHODS

We evaluated the histological changes after the long-term administration of BZC or PS on rat nasal respiratory mucosa. Forty rats were used for the BZC group and 40 rats for PS group. Animals in each group were divided into four subgroups The first subgroup received a low-concentration preservative solution that was commonly used for nasal sprays. The second subgroup received a high-concentration preservative solution that was reported to induce dermatitis in humans. The third and fourth subgroups received a steroid mixed preservative solution of low and high concentrations, respectively. The control group was administrated normal saline. After each group received 1, 2, and 4 weeks of topical administration, the symptomatic and histological changes on H&E stain were observed.

RESULTS

Sneezing and nasal rubbing with forelegs were observed in almost all subgroups by the seventh day of treatment. The preservatives induced nasal lesions, including intraepithelial glandular formation, inflammatory cell infiltration, vascular hyperplasia, and edematous change. The symptomatic and histological changes were pronounced with the prolonged duration of administration. Similar results were observed in the steroid mixed-solution groups. In the PS steroid mixed-solution group, however, symptoms and nasal lesions were reduced with the prolonged duration of administration.

CONCLUSION

It is our finding that even a low-concentration solution of preservative can lead to nasal lesion. Hence there is a strong need to develop both a preservative that can be safely and widely used and a nasal spray without preservatives.

Is the use of benzalkonium chloride as a preservative for nasal formulations a safety concern? A cautionary note based on compromised mucociliary transport

BACKGROUND

Topical nasal solution and suspension delivery systems are available for short- and long-acting vasoconstrictors, ipratropium, cromolyn, azelastine, and glucocorticosteroids. The use of intranasal glucocorticosteroids has increased substantially because the efficacy of these agents has been well established for the treatment of perennial and seasonal allergic rhinitis. Adverse local effects of burning, irritation, and dryness are occasionally associated with glucocorticosteroid nasal preparations. Benzalkonium chloride (BKC) is a quaternary ammonium antimicrobial agent included in some nasal solutions (including glucocorticosteroids) to prevent the growth of bacteria. Some reports suggest that BKC in nasal sprays may cause adverse effects, including reduced mucociliary transport, rhinitis medicamentosa, and neutrophil dysfunction.

OBJECTIVE

This article summarizes recent literature about possible adverse biologic effects associated with BKC as a nasal spray preservative by examining its effects on the following properties of mucociliary transport: ciliary motion, ciliary form, ciliary beat frequency, electron microscopy, and particle movement/saccharin clearance tests.

CONCLUSION

Both animal and human in vitro data suggest that BKC promotes ciliostasis and reduction in mucociliary transport that may be partially masked by absorption and dilution effects occurring in respiratory mucus. These possible confounding factors may account for several disparate human in vivo results. The use of BKC-free glucocorticosteroid formulations should be considered, particularly in patients who complain of nasal burning, dryness, or irritation.

A review of the preclinical and clinical data of newer intranasal steroids used in the treatment of allergic rhinitis

The anti-inflammatory activity of corticosteroids has prompted the exploration of their use in the treatment of allergic rhinitis. The development of intranasal steroids has resulted in several agents with quick actions, localized effects, and great efficacy in the treatment of seasonal allergic rhinitis and the prophylactic management of perennial rhinitis. This article presents a concise review of the preclinical and clinical evidence with these new agents and provides data-based guidance for the selection of optimal agents. The survey reveals that mometasone furoate, a new inhaled steroid with topical activity, has the greatest binding affinity for the glucocorticoid receptor, followed by fluticasone propionate, budesonide, triamcinolone acetonide, and dexamethasone. Mometasone furoate also has strong anti-inflammatory activity, with IL-4 and IL-5 inhibition activities equivalent to those of fluticasone propionate. Clinically, both mometasone furoate and fluticasone propionate appear to be well tolerated, to have quick onsets of action, and to be equivalent in efficacy in the treatment of seasonal allergic and perennial rhinitis. Of the intranasal steroids currently available, mometasone furoate has been shown to have the least systemic availability and, consequently, is expected to have the fewest systemic side effects. Some suppression of overnight cortisol levels has been reported with fluticasone propionate (indicative of hypothalamic-pituitary-adrenal axis suppression).

Pharmaceutical properties of fluticasone propionate nasal drops: a new formulation

A variety of corticosteroid delivery systems have been considered for the treatment of nasal polyposis. Safety considerations favour local delivery of the drug to the nasal cavity. No topical delivery system is entirely without problems, however, and formulations must address issues of microbiological quality, drug stability, reproducible drug delivery and adequate drug distribution at site, while also offering environmental and patient acceptability. Fluticasone propionate has been formulated in a new nasal drop preparation. As a highly water-insoluble compound, the active fluticasone propionate requires micronization to an optimal particle size and subsequent dispersion with a surface-active wetting agent. The product is presented in a unit dose low-density polyethylene container, manufactured by a blow-fill-seal process and stored in an aluminium foil overwrap. Micronized active has been used to promote optimal local drug delivery, and excipients have been selected for low irritancy potential and high formulation stability. There is no microbiological risk with fluticasone propionate unit dose nasal drops 400 microg and therefore no need to include a preservative in the preparation. They provide a convenient and effective treatment option for patients with nasal polyposis.