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

Pharmacology, particle deposition and drug administration techniques of intranasal corticosteroids for treating allergic rhinitis

This review presents an overview of the available literature regarding intranasal corticosteroids (INCs) for the treatment of allergic rhinitis (AR). Various treatment options exist for AR including INCs, antihistamines and leucotriene antagonists. INCs are considered to be the most effective therapy for moderate-to-severe AR, as they are effective against nasal and ocular symptoms and improve quality of life. Their safety has been widely observed. INCs are effective and safe for short-term use. Local adverse events are observed but generally well-tolerated. The occurrence of (serious) systemic adverse events is unlikely but cannot be ruled out. There is a lack of long-term safety data. INC may cause serious eye complications. The risk of INCs on the hypothalamic-pituitary-adrenal axis, on bone mineral density reduction or osteoporosis and on growth in children, should be considered during treatment. Pharmacological characteristics of INCs (e.g. the mode of action and pharmacokinetics) are well known and described. We sought to gain insight into whether specific properties affect the efficacy and safety of INCs, including nasal particle deposition, which the administration technique affects. However, advances are lacking regarding the improved understanding of the effect of particle deposition on efficacy and safety and the effect of the administration technique. This review emphasizes the gaps in knowledge regarding this subject. Advances in research and health care are necessary to improve care for patients with AR.

The effect of ingredients commonly used in nasal and inhaled solutions on the secretion of mucus in vitro

Hypersecretion of mucus is associated with impaired mucociliary clearance that can influence the retention of active pharmaceutical ingredients in the airway but is also linked with recurrent airway disease. Therefore, the effect on mucin secretion of a range of ingredients used in solutions delivered to the nose and lung was studied. Mucin secretion from explants of ovine epithelium was quantified using an enzyme-linked lectin assay (ELLA) or sandwich ELLA depending on the compatibility of the ingredients with the assay. Benzalkonium chloride (0.015% w/w), Methocel™ E50 premium LV (1.0% w/w), propylene glycol (1.5% w/w), potassium sorbate + propylene glycol (0.3% w/w + 1.5% w/w) and polysorbate 80 (0.025% w/w), used at common working concentrations, all increased the secretion of mucin from the explants (P < 0.05). Ethylenediamine tetraacetic acid-disodium salt (EDTA) (0.015% w/w), Avicel® RC591 (1.5% w/w), fluticasone furoate (0.0004% w/w, concentration in solution) and dimethyl sulfoxide (DMSO) (0.2% w/w) did not affect mucin secretion. Compounds increasing mucin secretion could alter the rate of mucociliary clearance and the mucus could provide a barrier to drug absorption. This could predispose patients to disease and affect the activity of delivered drugs, decreasing or increasing their clinical efficacy.

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.

Conceptual Model for Using Imidazoline Derivative Solutions in Pulpal Management

Alpha-adrenergic agonists, such as the Imidazoline derivatives (ImDs) of oxymetazoline and xylometazoline, are highly effective hemostatic agents. ImDs have not been widely used in dentistry but their use in medicine, specifically in ophthalmology and otolaryngology, warrants consideration for pulpal hemostasis. This review presents dental healthcare professionals with an overview of ImDs in medicine. ImD solutions have the potential to be more effective and biocompatible than existing topical hemostatic compounds in pulpal management. Through a comprehensive analysis of the pharmacology of ImDs and the microphysiology of hemostasis regulation in oral tissues, a conceptual model of pulpal management by ImD solutions is presented.

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.

Just how prevalent are peptide therapeutic products? A critical review

How prevalent are peptide therapeutic products? How innovative are the formulations used to deliver peptides? This review provides a critical analysis of therapeutic peptide products and the formulations approved by the United States Food and Drug administration (FDA), the European Medicines Agency (EMA), and the Japanese Pharmaceuticals and Medical Devices Agency (PMDA). This review also provides an in-depth analysis of dosage forms and administration routes for delivering peptide therapeutics, including injectables, oral dosage forms, and other routes of administration. We discuss the function of excipients in parenteral formulations in detail, since most peptide therapeutics are parenterally administered. We provide case studies of alternate delivery routes and dosage forms. Based on our analysis, therapeutic peptides administered as injectables remain the most commonly used dosage forms, particularly in the form of subcutaneous, intravenous, or intramuscular injections. In addition, therapeutic peptides are formulated to achieve prolonged release, often through the use of polymer carriers. The limited number of oral therapeutic peptide products and their poor absorption and subsequent low bioavailability indicate a need for new technologies to broaden the formulation design space. Therapeutic peptide products may also be delivered through other administration routes, including intranasal, implant, and sublingual routes. Therefore, an in-depth understanding of how therapeutic peptides are now formulated and administered is essential to improve peptide delivery, improve patient compliance, and reduce the healthcare burden for these crucial therapeutic agents.

Orabase-Formulated Benzalkonium Chloride Effectively Suppressed Oral Potentially Malignant Disorder In Vitro and In Vivo

Oral potentially malignant disorder (OPMD) is associated with an increased risk of progression to oral cancer. Patients with dysplastic changes of the precancerous lesions have a higher malignant transformation rate than those without dysplastic changes. Radiotherapy and surgery are the traditionally preferred choices for OPMD treatment. However, side effects caused by radiotherapy and surgery may reduce the willingness of patients to accept therapy. Therefore, developing an Orabase-formulated drug, which can be non-invasively administered, may provide an alternative treatment choice. To find, verify, and develop a new anti-cancer drug cost a lot of time and money, while drug repurposing can shorten both time and cost. In this study, we utilized high-throughput screening library to identify clinical drugs, which may have new bioactivities. Herein, we report that benzalkonium chloride (BAK), an antimicrobial preservative for pharmaceutical products, significantly induced reactive oxygen species production and cell death in oral precancerous cells. Additionally, our results showed that phosphorylation of STAT3 (Tyr705) and Akt (Ser473) were involved in cell death caused by BAK in DOK cells. According to animal studies, the development of DMBA-induced oral precancerous lesions was inhibited by 2% BAK. In conclusion, Orabase-formulated BAK may be a potential treatment for OPMD in the future.

Influence of Intranasal Drugs on Human Nasal Mucociliary Clearance and Ciliary Beat Frequency

The nasal mucociliary clearance system, which comprises epithelial cilia and mucus from goblet cells, is an important intrinsic defense mechanism of the upper respiratory tract. Intranasal drugs and additives can have a detrimental effect on ciliary activity and mucociliary clearance, and thus impact the integrity of nasal defense mechanisms. This article discusses the current literature on the effects of different classes of intranasal drugs including intranasal corticosteroids, antihistamines, decongestants, antimicrobials and antivirals, as well as various drug excipients and nasal irrigation solutions on human nasal mucociliary clearance and ciliary beat frequency. Available data indicate that some intranasal formulations tend to hamper nasal ciliary function and mucociliary clearance. Therefore, it is of great importance to assess the effects of intranasal drugs and additives on mucociliary function before they are recommended as therapy for different nasal conditions.

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)

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)

Once-Daily Administration of Intranasal Corticosteroids for Allergic Rhinitis: A Comparative Review of Efficacy, Safety, Patient Preference, and Cost

Background

The aim of this review was to compare the efficacy, safety, patient preference, and cost-effectiveness of once-daily budesonide aqueous nasal spray (BANS), fluticasone propionate nasal spray (FPNS), mometasone furoate nasal spray (MFNS), and triamcinolone aqueous nasal spray (TANS) for treatment of allergic rhinitis (AR) in adult patients.

Methods

A MEDLINE search (1966 to January 2004) was conducted to identify potentially relevant English language articles. Pertinent abstracts from recent allergy society meetings were identified also. The medical subject heading search terms included were intranasal corticosteroid (INS), nasal steroid, BANS, MFNS, FPNS, or TANS and AR. Selected studies were randomized, controlled, comparison trials of patients with AR treated with once-daily BANS, MFNS, FPNS, or TANS.

Results

All four INSs administered once daily were effective and well tolerated in the treatment of AR in adult patients, with similar efficacy and adverse event profiles. No differences were seen between INSs in systemic effects, except for significantly lower overnight urinary cortisol levels in healthy volunteers treated with FPNS compared with placebo. Based on sensory attributes, patients preferred BANS and TANS versus MFNS and FPNS. BANS was associated with more days of treatment per prescription at a lower cost per day for adults compared with the other INSs and is the only INS with a pregnancy category B rating.

Conclusion

BANS, FPNS, MFNS, and TANS have similar efficacy and safety profiles. Differences in sensory attributes, documented safety during pregnancy, and cost may contribute to better patient acceptance of one INS versus another and promote better adherence to therapy.

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.

Antimicrobial Effects of Sulfonyl Derivative of 2(5H)-Furanone against Planktonic and Biofilm Associated Methicillin-Resistant and -Susceptible Staphylococcus aureus

The gram-positive opportunistic bacterium Staphylococcus aureus is one of the most common causatives of a variety of diseases including skin and skin structure infection or nosocomial catheter-associated infections. The biofilm formation that is an important virulence factor of this microorganism renders the antibiotic therapy ineffective, because biofilm-embedded bacteria exhibit strongly increased tolerance to antimicrobials. Here, we describe a novel 3-chloro-5(S)-[(1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy]-4-[4-methylphenylsulfonyl]-2(5H)-furanone (F105), possessing a sulfonyl group and l-menthol moiety. Minimal inhibitory and bactericidal concentration values (MIC and MBC) of F105 were 10 and 40 mg/L, respectively, suggesting F105 biocidal properties. F105 exhibits pronounced activity against biofilm-embedded S. aureus and increases the efficacy of aminoglycosides (amikacin, gentamicin, and kanamycin) and benzalkonium chloride with fractional inhibitory concentration index values of 0.33–0.44 and 0.29, respectively, suggesting an alternative external treatment option, e.g., for wound infections. Moreover, low concentrations (0.5–1.3 mg/L) of F105 reduced the MICs of these antimicrobials twofold. By using confocal laser scanning microscopy and CFU counting, we show explicitly that F105 also restores the antimicrobial activity of gentamicin and ampicillin against S. aureus biofilms by several orders of magnitude. Biofilm structures were not destroyed but sterilized, with embedded cells being almost completely killed at twofold MBC. While F105 is quite toxic (CC₅₀/MBC ratio 0.2), our data suggest that the F105 chemotype might be a promising starting point for the development of complex topical agents for combined anti-staphylococcal biofilm-therapies restoring the efficacy of some antibiotics against difficult to treat S. aureus biofilm.

Paradoxical bronchospasm from benzalkonium chloride (BAC) preservative in albuterol nebulizer solution in a patient with acute severe asthma. A case report and literature review of airway effects of BAC

Nebulized bronchodilator solutions are available in the United States as both nonsterile and sterile-filled products. Sulfites, benzalkonium chloride (BAC), or chlorobutanol are added to nonsterile products to prevent bacterial growth. Bronchoconstriction from inhaled BAC is cumulative, prolonged, and correlates directly with basal airway responsiveness. The multi-dose dropper bottle of albuterol sulfate solution contains 50 μg BAC per/2.5 mg of albuterol, which may be below or at the lower limit of the threshold dose for bronchoconstriction. However, with repeated albuterol nebulization, the effect can be additive and cumulative, often exceeding the bronchoconstriction threshold. We report a case of a 17 years old patient, who received 32 mg of BAC via nebulization over a period of 3.5 days that probably caused persistent bronchospasm evidenced by failure to improve clinically and to increase peak expiratory flow rate (PEFR) from 125 L/min (27% of predicted value) to 300 L/min (68% of predicted value) within 2 hours of withdrawing BAC. The patient's respiratory status and PEFR improved dramatically once the nebulization solution was switched to BAC free lev-albuterol solution. The pediatric providers, particularly the emergency department physicians, intensivists and pulmonologists need to be aware of this rare albeit possible toxicity to the respiratory system caused by BAC used as a preservative in albuterol nebulizer solution.

Fluconazole-Pyridoxine Bis-Triazolium Compounds with Potent Activity against Pathogenic Bacteria and Fungi Including Their Biofilm-Embedded Forms

Two novel quaternary ammonium salts, bis-triazolium derivatives of fluconazole and pyridoxine, were synthesized by reaction of fluconazole with pyridoxine-based synthetic intermediates. The leading compound demonstrated pronounced antimycotic and antibacterialin vitroactivity, comparable to or exceeding that of the reference antifungal (fluconazole, terbinafine) and antibacterial/antiseptic (miramistin, benzalkonium chloride) agents. In contrast to many antimicrobials, the leading compound was also active against biofilm-embedded staphylococci andEscherichia coli. While no biofilm structure destruction occurred, all compounds were able to diffuse into the matrix and reduce the number of colony-forming units by three orders of magnitude at 16 × MBC. The leading compound was significantly less toxic than miramistin and benzalkonium chloride and more toxic than the reference antifungal drugs. The obtained results make the described chemotype a promising starting point for the development of new broad-spectrum antimicrobial therapies with powerful effect on fungal and bacterial pathogens including their biofilm-embedded forms.

Management of Allergic Rhinitisand Sinusitis

Allergic rhinitis and sinusitis are chronic conditions of the airway and cause significant morbidity. Both can require pharmacotherapy with nonprescription products to relieve symptoms or with prescription products to treat the underlying pathophysiology. Because these diseases are prevalent conditions, the pharmacist is in the unique position of being the first health professional contact for many patients. The pharmacist can assist the patient in selection of nonprescription antihistamines, decongestants, and nasal saline sprays as well as provide instruction on the use of steam therapy, aromatic vapors, and warm compresses for the relief of symptoms. Equally important, the pharmacist can encourage patients to seek care from a physician when treatment with intranasal corticosteroids, antibiotics, and nonsedating antihistamines are needed.

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.

The effect of drugs and other compounds on the ciliary beat frequency of human respiratory epithelium

BACKGROUND

Cilia in the human respiratory tract play a critical role in clearing mucus and debris from the airways. Their function can be affected by a number of drugs or other substances, many of which alter ciliary beat frequency (CBF). This has implications for diseases of the respiratory tract and nasal drug delivery. This article is a systematic review of the literature that examines 229 substances and their effect on CBF.

METHODS

MEDLINE was the primary database used for data collection. Eligibility criteria based on experimental design were established, and 152 studies were ultimately selected. Each individual trial for the substances tested was noted whenever possible, including concentration, time course, specific effect on CBF, and source of tissue.

RESULTS

There was a high degree of heterogeneity between the various experiments examined in this article. Substances and their general effects (increase, no effect, decrease) were grouped into six categories: antimicrobials and antivirals, pharmacologics, human biological products, organisms and toxins, drug excipients, and natural compounds/other manipulations.

CONCLUSION

Organisms, toxins, and drug excipients tend to show a cilioinhibitory effect, whereas substances in all other categories had mixed effects. All studies examined were in vitro experiments, and application of the results in vivo is confounded by several factors. The data presented in this article should be useful in future respiratory research and examination of compounds for therapeutic and drug delivery purposes.

Brazilian Academy of Rhinology position paper on topical intranasal therapy

This documents aims at educating those who treat sinonasal diseases - both general practitioners and specialists - about topical nasal treatments. By means of scientific evidence reviews, the Brazilian Academy of Rhinology provides its practical and updated guidelines on the most utilized topical nasal medication, except for the drugs that have topical antibiotics in their formulas.

Fluticasone furoate nasal spray in the treatment of allergic rhinitis

Allergic rhinitis (AR) is a prevalent disease with great morbidity and significant societal and economic burden. Intranasal corticosteroids are recommended as first-line therapy for patients with moderate-to-severe disease, especially when nasal congestion is a major component of symptoms. To compare the efficacy and safety profile of different available intranasal corticosteroids for the treatment of AR, it is important to understand their different structures and pharmacokinetic and pharmacodynamic properties. Knowledge of these drugs has increased tremendously over the last decade. Studies have elucidated mechanisms of action, pharmacologic properties, and the clinical impact of these drugs in allergic respiratory diseases. Although the existing intranasal corticosteroids are already highly efficient, the introduction of further improved formulations with a better efficacy/safety profile is always desired. Fluticasone furoate nasal spray is a new topical corticosteroid, with enhanced-affinity and a unique side-actuated delivery device. As it has high topical potency and low potential for systemic effects, it is a good candidate for rhinitis treatment.

Physiology and pathophysiology of respiratory mucosa of the nose and the paranasal sinuses

In this review, anatomy and physiology of the respiratory mucosa of nose and paranasal sinuses are summarized under the aspect of its clinical significance. Basics of endonasal cleaning including mucociliary clearance and nasal reflexes, as well as defence mechanisms are explained. Physiological wound healing, aspects of endonasal topical medical therapy and typical diagnostic procedures to evaluate the respiratory functions are presented. Finally, the pathophysiologies of different subtypes of non-allergic rhinitis are outlined together with treatment recommendations.

Genotoxicity of unmodified and organo-modified montmorillonite

The natural clay mineral montmorillonite (Cloisite) Na+) and an organo-modified montmorillonite (Cloisite 30B) were investigated for genotoxic potential as crude suspensions and as suspensions filtrated through a 0.2-microm pore-size filter to remove particles above the nanometre range. Filtered and unfiltered water suspensions of both clays did not induce mutations in the Salmonella/microsome assay at concentrations up to 141microg/ml of the crude clay, using the tester strains TA98 and TA100. Filtered and unfiltered Cloisite) Na+ suspensions in culture medium did not induce DNA strand-breaks in Caco-2 cells after 24h of exposure, as tested in the alkaline comet assay. However, both the filtered and the unfiltered samples of Cloisite 30B induced DNA strand-breaks in a concentration-dependent manner and the two highest test concentrations produced statistically significantly different results from those seen with control samples (p<0.01 and p<0.001) and (p<0.05 and p<0.01), respectively. The unfiltered samples were tested up to concentrations of 170microg/ml and the filtered samples up to 216microg/ml before filtration. When tested in the same concentration range as used in the comet assay, none of the clays produced ROS in a cell-free test system (the DCFH-DA assay). Inductively coupled plasma mass-spectrometry (ICP-MS) was used to detect clay particles in the filtered samples using aluminium as a tracer element characteristic to clay. The results indicated that clay particles were absent in the filtered samples, which was independently confirmed by dynamic light-scattering measurements. Detection and identification of free quaternary ammonium modifier in the filtered sample was carried out by HPLC-Q-TOF/MS and revealed a total concentration of a mixture of quaternary ammonium analogues of 1.57microg/ml. These findings suggest that the genotoxicity of organo-modified montmorillonite was caused by the organo-modifier. The detected organo-modifier mixture was synthesized and comet-assay results showed that the genotoxic potency of this synthesized organo-modifier was in the same order of magnitude at equimolar concentrations of organo-modifier in filtrated Cloisite) 30B suspensions, and could therefore at least partly explain the genotoxic effect of Cloisite) 30B.

Assessment of Upper Respiratory Tract and Ocular Irritative Effects of Volatile Chemicals in Humans

Accurate assessment of upper respiratory tract and ocular irritation is critical for identifying and remedying problems related to overexposure to volatile chemicals, as well as for establishing parameters of irritation useful for regulatory purposes. This article (a) describes the basic anatomy and physiology of the human upper respiratory tract and ocular mucosae, (b) discusses how airborne chemicals induce irritative sensations, and (c) reviews practical means employed for assessing such phenomena, including psychophysical (e.g., threshold and suprathreshold perceptual measures), physiological (e.g., cardiovascular responses), electrophysiological (e.g., event-related potentials), and imaging (e.g., magnetic resonance imaging) techniques. Although traditionally animal models have been used as the first step in assessing such irritation, they are not addressed here since (a) there are numerous reviews available on this topic and (b) many rodents and rabbits are obligate nose breathers whose nasal passages differ considerably from those of humans, potentially limiting generalization of animal-based data to humans. A major goal of this compendium is to inform the reader of procedures for assessing irritation in humans and to provide information of value in the continued interpretation and development of empirical databases upon which future reasoned regulatory health decisions can be made.

New treatment options in allergic rhinitis: patient considerations and the role of ciclesonide

Allergic rhinitis (AR) is a chronic inflammatory respiratory disease affecting 5%-50% of the worldwide population and its prevalence is increasing (Herman 2007). In addition, AR is associated with asthma and other co-morbidities such as conjunctivitis and sinusitis. The main symptoms are nasal congestion, rhinorrea, sneezing, itching, and post-nasal drainage induced after allergen exposure by an IgE-mediated inflammation of the membranes lining the nose. AR is not a life-threatening disease, but it has been shown to have a significant impact on quality of life. The Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines propose a classification of AR in intermittent and persistent, each graded as mild or moderate-severe, and provide a stepwise approach to the treatment. Inhaled steroids and antihistamine are the main tools in AR therapy but more safe and effective drugs are, however, needed. Inhaled steroid ciclesonide appears to be safe and effective.

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.

Effectiveness of ciclesonide nasal spray in the treatment of seasonal allergic rhinitis

BACKGROUND

Ciclesonide is an investigational corticosteroid under development for treatment of allergic rhinitis. Ciclesonide is converted to active metabolite, desisobutyryl-ciclesonide (des-CIC), by upper and lower airway esterases. In vitro studies in human nasal epithelial cells and bronchial epithelial cells have demonstrated a long duration of anti-inflammatory activity of des-CIC.

OBJECTIVE

To evaluate the dose-dependent efficacy and safety of a hypotonic intranasal formulation of ciclesonide in patients with seasonal allergic rhinitis (SAR).

METHODS

This was a phase 2, randomized, parallel-group, double-blind, placebo-controlled study. Adults (n = approximately 145 per treatment group) with a minimum 2-year history of SAR received placebo or ciclesonide (25, 50, 100, or 200 microg/d) for 14 days. The primary end point was change in the sum of morning and evening reflective total nasal symptom scores (TNSSs) over 2 weeks. Safety was monitored throughout the study.

RESULTS

Ciclesonide, 100 microg/d (P = .04) and 200 microg/d (P = .003), significantly improved the sum of morning and evening reflective TNSS vs placebo at more than 2 weeks of treatment. Baseline values for morning and evening reflective TNSS ranged from 17.80 to 18.82 across treatment groups. The average change from baseline in reflective TNSS was -4.2 for placebo and -4.8, -4.8, -5.3, and -5.8 for ciclesonide, 25, 50, 100, and 200 microg/d, respectively. There were no dose-related differences in the incidence of adverse events among treatment groups.

CONCLUSIONS

Results from this study indicate that 100-microg and 200-microg daily doses of ciclesonide are effective in the treatment of SAR. Ciclesonide, 200 microg/d, appears to be the optimal dose studied for reducing the symptoms of SAR while maintaining an acceptable safety profile.

In vitro genotoxicity and cytotoxicity of benzalkonium chloride

Benzalkonium chloride (BAC) acts as a preservative in numerous nasal preparations. Possible genotoxic and cytotoxic effects of BAC in human respiratory epithelial BEAS-2B cells should be investigated in vitro. Cell cultures were exposed for 2h to BAC in concentrations ranging from 0.002% to 0.05%. Methyl methanesulfonate served as positive control, PBS as negative control. The tail moment of single-cell gel-electrophoresis (SCGE) was used to assess BAC-induced DNA damage. Cell viability was measured by trypan blue dye exclusion staining. Additionally, the critical micellar concentration (CMC) of BAC in PBS was detected. The tail moment increased dose dependently with the maximum value at 0.02%, and declined for higher concentrations. Nearly all cells died at low BAC concentrations up to 0.01%. Above this concentration cell viability increased. The CMC of BAC in PBS was estimated to be 0.02%. BAC caused relevant DNA changes in respiratory epithelial cells in vitro at concentrations commonly employed in commercially available nasal preparations. Some of the exposed cells survived. In further studies it could be considered to look whether these cells would still be able to proliferate and possibly fix the damage that they have possibly accumulated into an actual mutation using for example the induction of micronuclei.

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.

Effect of topical nasal steroid sprays on nasal mucosa and ciliary function

PURPOSE OF REVIEW

This review was conducted to examine current evidence focusing on the effect of nasal steroid sprays on nasal ciliary function.

RECENT FINDINGS

Review of current literature suggests that long term effects of topical corticosteroid nasal sprays are safe and fail to cause damage to local nasal structure and function.

SUMMARY

The use of corticosteroid nasal sprays for the treatment of allergic rhinitis is widely accepted. Popularity of this class of medications is based on a well-established combination of efficacy, tolerability, and safety. Although current literature suggests that the use of intranasal steroids is indeed safe, increasing indications for prolonged administration continue to fuel debate regarding the long-term effect on local nasal structure and function. The purpose of this article is to review current literature addressing the effects of the components of local intranasal steroid sprays on the structure and function of the nasal mucosa.

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.

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.

Techniques of intranasal steroid use

OBJECTIVE

The effectiveness of topical intranasal steroids (INS) sprays for the treatment of allergic and nonallergic rhinitis may be limited by lack of instruction in the optimal spray technique. To determine whether the technique used affects the efficacy and safety of the product, this review of evidence had the goal of identifying and establishing a preferred method of applying INS sprays.

STUDY DESIGN

A MEDLINE search of pertinent literature on 7 INS and 1 intranasal antihistamine spray preparations conducted with the use of appropriate search terms, yielded an initial 121 articles, 29 of which were identified as appropriate for review and grading for quality of evidence.

RESULTS

The analysis provided no definitive evidence regarding how best to instruct patients to use INS or antihistamine spray devices.

CONCLUSIONS

On the basis of a lack of clear evidence regarding instructions to maximize efficacy and safety of these drugs, the panel recommended a 7-step standard technique.

A comparison of nasal clearance after treatment of perennial allergic rhinitis with budesonide and mometasone

OBJECTIVE

Evidence in vitro suggests that benzalkonium chloride, a preservative in many intranasal preparations, interferes with ciliary function and thus could potentially interfere with mucociliary transport, the mechanism for clearing secretions from the nasal cavity.

STUDY DESIGN

We performed a parallel randomized study with 10 subjects in each arm comparing Rhinocort AQUA (an intranasal steroid [budesonide] spray without benzalkonium chloride) and Nasonex (an intranasal steroid [mometasone furoate] spray with benzalkonium chloride). Before and after 2 weeks of treatment, subjects completed a Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) and underwent a measurement of nasal clearance of a radioactive colloidal spray into the nose.

RESULTS

The groups were matched at entry for nasal clearance, even though there was variability among subjects. The amount of change after 2 weeks of treatment (Delta before versus after treatment) showed a significant difference in nasal clearance favoring budesonide. After 2 weeks of treatment, both budesonide and mometasone demonstrated overall improvement in quality of life as assessed by the RQLQ. Both treatments were well tolerated.

CONCLUSION

Our study extends the observation in vitro that demonstrates the adverse effect of benzalkonium chloride on cilia to a measurement in vivo of clearance. The effects after 2 weeks might not reflect changes after longer periods of treatment.

SIGNIFICANCE

To determine the clinical significance of the small improvement in mucociliary transport will require large clinical trials.

The production of transgenic pigs for potential use in clinical xenotransplantation: microbiological evaluation

Debate over the infection hazards of pig-to-human xenotransplantation has focused mainly on the porcine endogenous retroviruses (PERV). However, hazards of exogenous infectious agents possibly associated with the xenograft have also been evaluated (Xenotransplantation 2000; 7: 143). We report the results of a health monitoring program demonstrating the exclusion of more than 80 potential pathogens from nine cohorts of pigs reared in a high welfare bioexclusion facility as potential xenograft source animals. A dynamic bacterial flora of pigs reared under barrier conditions was characterized, emphasizing the significance of monitoring for multiresistant antimicrobial sensitivity patterns. Evidence was found for exclusion of two commonly residual exogenous viruses, porcine cytomegalovirus and porcine lymphotropic herpesviruses, among a proportion of the cohorts tested. Finally, there was histopathological evidence for low grade pneumonitis among sentinel pigs, likely to have been associated with the use of quaternary ammonium disinfectants during the production process, indicating a need for review of toxicology data for disinfectant agents used in such bioexclusion systems. Intensive health monitoring programs, based upon regularly updated recommendations from the microbiological research community, will enable significant reductions in the potential hazards associated with pig-to-human xenotransplantation.

Comparison of the clinical efficacy of standard and mucoadhesive-based nasal decongestants

AIMS

To compare two xylometazoline 0.1% preparations: reference commercial solution (RS) and test mucoadhesive solution (TS).

METHODS

Twenty subjects with perennial allergic rhinitis (age range 18-69 years, 5 atopic, 7 men) applied randomly in turn TS and RS for 5 days in a double-blind crossover clinical trial. Nasal airflow resistance (NAR), nasal symptoms (6 grade scoring), frequency of application (times/day), and side-effects were recorded.

RESULTS

Mean ratio TS/RS of areas under the resistance/time curves for NAR +/- 90% CI: 3.56 +/- 0.92; mean TS-RS differences +/- 95% CI: for congestion: -1.12 +/- 0.59, for frequency of application: -1.10 +/- 0.20. Subjects experienced fewer side-effects with TS.

CONCLUSIONS

A mucoadhesive solution with a decongestant had a greater and longer lasting effect on nasal congestion in subjects with perennial allergic rhinitis than the commercially available decongestant solution. It also caused fewer side effects.

Clinical prescribing of allergic rhinitis medication in the preschool and young school-age child: what are the options?

Allergic rhinitis (AR) is the most common chronic condition in children and is estimated to affect up to 40% of all children. It is usually diagnosed by the age of 6 years. The major impact in children is due to co-morbidity of sinusitis, otitis media with effusion, and bronchial asthma. AR also has profound effects on school absenteeism, performance and quality of life. Pharmacotherapy for AR should be based on the severity and duration of signs and symptoms. For mild, intermittent symptoms lasting a few hours to a few days, an oral second-generation antihistamine should be used on an as-needed basis. This is preferable to a less expensive first-generation antihistamine because of the effect of the latter on sedation and cognition. Four second-generation antihistamines are currently available for children under 12 years of age: cetirizine, loratadine, fexofenadine and azelastine nasal spray; each has been found to be well tolerated and effective. There are no clearcut advantages to distinguish these antihistamines, although for children under 5 years of age, only cetirizine and loratadine are approved. Other agents include pseudoephedrine, an oral vasoconstrictor, for nasal congestion, and the anticholinergic nasal spray ipratropium bromide for rhinorrhoea. Sodium cromoglycate, a mast cell stabiliser nasal spray, may also be useful in this population. For patients with more persistent, severe symptoms, intranasal corticosteroids are indicated, although one might consider azelastine nasal spray, which has anti- inflammatory activity in addition to its antihistamine effect. With the exception of fluticasone propionate for children aged 4 years and older, and mometasone furoate for those aged 3 years and older, the other intranasal corticosteroids including beclomethasone dipropionate, triamcinolone, flunisolide and budesonide are approved for children aged 6 years and older. All are effective, so a major consideration would be cost and safety. For short term therapy of 1 to 2 months, the first-generation intranasal corticosteroids (beclomethasone dipropionate, triamcinolone, budesonide and flunisolide) could be used, and mometasone furoate and fluticasone propionate could be considered for longer-term treatment. Although somewhat more costly, these second-generation drugs have lower bioavailability and thus would have a better safety profile. In patients not responding to the above programme or who require continuous medication, identification of specific triggers by an allergist can allow for specific avoidance measures and/or immunotherapy to decrease the allergic component and increase the effectiveness of the pharmacological regimen.

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.