REVIEW ARTICLE
`Safety review of benzalkonium chloride used as a
`preservative in intranasal solutions: An overview of
`conflicting data and opinions
`BRADLEY MARPLE, MD, PETER ROLAND, MD, and MICHAEL BENNINGER, MD, Dallas, Texas
`
`BACKGROUND: For most multiuse aqueous nasal,
`ophthalmic, and otic products, benzalkonium chlo-
`ride (BKC) is the preservative of choice. The Amer-
`ican 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. How-
`ever, over the past several years there have been
`conflicting reports of damage to human nasal epi-
`thelia and/or exacerbation of rhinitis medicamen-
`tosa associated with intranasal products containing
`BKC.
`OBJECTIVE: We sought to review the published liter-
`ature 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 rhi-
`nitis 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 concentra-
`tions ranging from 0.00045% to 0.1%. Eight studies,
`including a 6-month and 1-year long-term treat-
`ment study, demonstrated no toxic effects associ-
`ated with BKC,
`indicating that BKC was neither
`harmful to nasal tissue nor prone to exacerbate
`
`From the Department of Otolaryngology–Head and Neck
`Surgery, University of Texas Southwestern Medical Cen-
`ter.
`Reprint requests: Bradley Marple, MD, Department of Oto-
`laryngology–Head and Neck Surgery, University of Texas
`Southwestern Medical Center, 5323 Harry Hines Blvd,
`Dallas, TX 75390; e-mail, bradley.marple@utsouthwestern.
`edu.
`0194-5998/$30.00
`Copyright © 2004 by the American Academy of Otolaryn-
`gology–Head and Neck Surgery Foundation, Inc.
`10.1016/j.otohns.2003.07.005
`
`rhinitis medicamentosa. Furthermore, of the 10 stud-
`ies that concluded that BKC resulted in degenera-
`tive 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 signif-
`icant differences between BKC and placebo or ac-
`tive 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 toler-
`ated for both long- and short-term clinical use.
`(Otolaryngol Head Neck Surg 2004;130:131-41.)
`
`Benzalkonium chloride (BKC) is a quaternary
`ammonium compound that has been in clinical use
`since 19351as an antimicrobial additive. It has
`been used to maintain the sterility of a variety of
`prescription and over-the-counter products, such
`as cosmetics, infant care products, and pharma-
`ceutical nasal sprays, ophthalmic solutions, and
`otic drops.2 As reported in the Journal of Ameri-
`can College of Toxicology, the Cosmetic Ingredi-
`ent Review panel concluded that BKC can be
`safely used as an antimicrobial agent at concen-
`trations up to 0.1%.2 However, over the past
`several years, reports of damage to human nasal
`epithelia and/or exacerbation of rhinitis medica-
`mentosa associated with intranasal products con-
`taining BKC have emerged.3-7
`The objective of this article was to review the
`published literature specific to these safety issues
`to determine whether sufficient, clinically signifi-
`cant data exist to confirm that intranasal products
`containing BKC cause actual damage to human
`
`131
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`132 MARPLE et al
`
`nasal epithelia or exacerbate rhinitis medicamen-
`tosa.
`
`MATERIALS AND METHODS
`A MEDLINE literature search was conducted
`from 1980 to February 2003 for in vivo and in
`vitro studies that evaluated the effects of BKC on
`nasal epithelia. The search identified a total of 18
`preclinical and clinical studies. An overview of the
`study methods are presented as follows:
`
`In Vivo Studies
`There were 14 in vivo studies, with 11 using
`human subjects and 3 using animal subjects. A
`variety of different techniques and methods were
`used in each of the studies. Nasal biopsy samples,
`when taken, were harvested from different nasal
`locations. Changes in ultrastructural ciliary form
`and function were determined by various types of
`microscopy, including light microscopy (LM),8-13
`transmission electron microscopy (TEM),9,12
`scanning electron microscopy (SEM),9,12 and in-
`verted phase microscopy (IPM).14 Direct muco-
`ciliary clearance was evaluated via indigo carmine
`saccharine transport time (ICST)10,15 or saccha-
`rine clearance time (SCT).14 Exacerbation of rhi-
`nitis medicamentosa was determined by changes
`in nasal epithelia thickness15,16 (Tables 1 and 2).
`
`In Vitro Studies
`There were 4 in vitro studies. As with the in
`vivo studies, a variety of methodologies were
`used. Indirect mucociliary clearance via ciliary
`beat frequency was determined using cultured cil-
`iated chick embryo tracheas or human ciliated
`adenoid or nasal epithelial tissue. Changes in ul-
`trastructural ciliary form and function were deter-
`mined by various types of microscopy, including
`LM,12,17 TEM,12 SEM,12 and IPM (Tables 1 and
`2).
`
`RESULTS: SUMMARY OF PUBLISHED
`STUDIES
`Of the 18 studies identified, 8 concluded there
`were no toxic effects associated with BKC and 10
`concluded that BKC was detrimental to nasal ep-
`ithelium or exacerbated rhinitis medicamentosa at
`concentrations of BKC ranging from 0.1 mg/mL
`to 0.02%.
`
`Otolaryngology–
`Head and Neck Surgery
`January 2004
`
`The studies that concluded there were no toxic
`effects associated with BKC are summarized in
`Table 1. All were in vivo (7 human, 1 animal) and
`were well powered to detect statistically signifi-
`cant differences in nasal epithelium histology or
`function due to exposure to BKC 0.1% to 0.02%.
`Within this group of studies, no statistically sig-
`nificant differences were noted between treatment
`groups that would indicate BKC was either harm-
`ful to nasal tissue or exacerbated rhinitis medica-
`mentosa. The study that was longest in duration
`compared mucosal biopsy samples from patients
`receiving BKC-containing
`intranasal
`steroid
`sprays versus oral antihistamines for a period of 6
`months. No significant differences were noted be-
`tween any of the treatment arms, and no adverse
`effects on nasal mucosa were observed after 6
`months of treatment with triamcinolone acetonide
`(n ⫽ 21) or beclomethasone dipropionate (n ⫽ 26)
`aqueous nasal sprays containing BKC 0.02%.8
`The 10 studies that concluded there were toxic
`effects associated with BKC are summarized in
`Table 2 (human: 4 in vivo, 3 in vitro; animal: 2 in
`vivo, 1 in vitro). Of particular interest, Graf et
`al18,19 conducted 2 controlled studies that exam-
`ined the long-term effect of BKC on the nasal
`mucosa. In the first trial, patients were treated with
`either oxymetazoline containing BKC 0.01% or
`BKC-free oxymetazoline for a period of 30 days.
`Nasal mucosal swelling was indirectly measured
`using rhinostereometry and nasal reactivity was
`measured via histamine provocation. Patients
`treated with the oxymetazoline/BKC combination
`demonstrated significantly greater nasal mucosal
`swelling (P ⬍ .05). Unfortunately, interpretation
`of these data is unclear given that both groups that
`were evaluated had confirmed nasal mucosal
`swelling after 30 days and no placebo group was
`included for comparison.20 The second study by
`Graf et al18 challenged the authors’ interpretation
`of their earlier results by showing that patients
`treated with BKC-free oxymetazoline had signif-
`icantly more nasal stuffiness than those treated
`with BKC alone and those treated with placebo.
`With regard to nasal mucosal
`swelling, an
`ANOVA analysis yielded no significant difference
`among the groups.18 Further corroboration of
`these results was provided in a short-term study by
`Graf et al19 in 1999 that concluded that oxymeta-
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`Otolaryngology–
`Head and Neck Surgery
`Volume 130 Number 1
`
`zoline and xylometazoline nasal spray with or
`without BKC may be safely used for up to 10 days
`in patients with chronic untreated vasomotor rhi-
`nitis. In this study, there was no difference in the
`degree of nasal mucosa swelling and nasal stuffi-
`ness between patients treated with oxymetazoline
`containing BKC and patients treated with BKC-
`free oxymetazoline.19
`In another example, a preclinical placebo-con-
`trolled study with Sprague-Dawley rats exposed to
`both high (0.1%) and low (0.01%) BKC with and
`without triamcinolone acetonide showed BKC-as-
`sociated nasal epithelial changes after 1 week of
`exposure. However,
`the editor stated that
`this
`study was underpowered and that the standard
`deviations were too large and therefore statisti-
`cally valid conclusions could not be drawn.16
`Overall, only 2 of the 10 studies that concluded
`BKC to be detrimental to nasal mucosa and/or
`exacerbated rhinitis medicamentosa via swelling
`of nasal tissues were supported by significantly
`different results from placebo or active controls.
`Of interest, both of these studies also included the
`use of oxymetazoline, which is well known for its
`association with rhinitis medicamentosa.20,21
`
`Discussion
`Maintaining a sterile environment within mul-
`tidose medication delivery systems is a challenge
`fundamental to patient safety. Failure to provide
`such an environment risks patient inoculation with
`fungal, bacterial, and viral pathogens, which can
`lead to life- and health-threatening consequences.
`This issue has prompted health regulation organi-
`zations, such as the US and European pharmaco-
`poeias, to issue strict criteria regarding mainte-
`nance of product sterility. Unfortunately, very few
`new antimicrobial preservatives have been intro-
`duced to the market over the course of the past 4
`decades. During the same time period many older
`preservatives have been withdrawn from the mar-
`ket due to concerns of tissue toxicity.22 BKC,
`which has been in clinical use since 1935 and
`approved for use as a preservative by the Food and
`Drug Administration since 1982, has been used
`effectively in its role as a preservative.1 Its use in
`a variety of prescription and over-the-counter
`products (eg, cosmetic,
`including infant care;
`pharmaceutical and over-the-counter nasal sprays,
`
`MARPLE et al 133
`
`ophthalmic solutions, and otic products) has of-
`fered a long history demonstrating both safety and
`effectiveness.
`Review of the current published literature, how-
`ever, reveals an emerging concern that exposure of
`nasal epithelia to BKC may lead to induction of
`pathologic or histologic changes within nasal ep-
`ithelial tissue or possibly exacerbate rhinitis me-
`dicamentosa by causing increased swelling of na-
`sal epithelium. Further, if this concern is valid, it
`follows that these effects might be time or con-
`centration dependent. The impact of these issues
`to patient safety is of obvious concern to practi-
`tioners.
`A number of studies have been designed and
`performed over the course of the past 3 decades in
`an attempt to address these concerns. Unfortu-
`nately, a number of different confounding issues
`have led to continued confusion surrounding
`safety concerns of BKC. Differences in study de-
`sign, analysis of data, and choice of outcome pa-
`rameters are among only some of the factors that
`have contributed to a lack of consensus regarding
`the safety of BKC. One striking and relatively
`consistent difference that emerges when these
`studies are cumulatively reviewed is the discrep-
`ancy between in vitro and in vivo data. Although
`examination of data provided by in vitro studies
`raises some concern regarding the safety of
`BKC,3,12,17,23 examination of available in vivo
`data favors the safety of BKC.8-10,14,15,18,20,24,25
`Several factors that may lead to differences
`have been observed between basic science and
`clinical studies. One major contributing factor to
`this problem is the lack of a universally accepted
`in vitro model for standard evaluation of the ef-
`fects of preservatives on human nasal epithelium.
`The in vitro studies reviewed in the preparation of
`this report made use of a variety of different
`models and methods for evaluating BKC effects,
`giving rise to the possibility of significant differ-
`ences in outcomes. As an example, ciliated cells
`cultured from human adenoids used in some stud-
`ies were noted to be less susceptible to the cilio-
`toxic effects of preservatives than were chicken
`embryo tracheas used in other studies.26 In the
`end, researchers have been unable to duplicate
`results obtained from other studies, resulting in
`differing conclusions (Tables 1 and 2).
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`134 MARPLE et al
`
`Otolaryngology–
`Head and Neck Surgery
`January 2004
`
`Table 1. Summary of studies finding no toxic effects associated with benzalkonium chloride (BKC)
`
`Design
`
`Treatment materials/regimen
`
`Monkeys: FPANS 2x right nostril QID (n ⫽ 4), con-
`trol 5% glucose (n ⫽ 4)
`Rats: BDPANS 1 h via snout-only inhalation cham-
`ber (n ⫽ 12), control air only (n ⫽ 12).
`0.9% NaCl nasal solution with 0.01% thiomerisol or
`0.01% BKC, or 0.1% EDTA PBO, 0.9% NaCl
`
`Author
`
`Ainge et al24
`
`In vivo, nasal mucosa of rats (n ⫽ 24)
`and monkeys (n ⫽ 8) treated for 28 d
`
`Batts et al15
`
`In vivo, single-dose, single-center, active
`controlled, clinical study
`
`Braat et al17
`
`In vivo, 6-week, single-center, random-
`ized, double-blind, nasal biopsy study
`
`Klossek et al25
`
`In vivo, 24-week, randomized, prospec-
`tive, parallel-group, active controlled,
`open study
`
`PBO run-in: 2 sprays, BID each nostril ⫻2 wk;
`FPANS 200 ␮g/spray (n ⫽ 8) or PBO w/BKC (n
`⫽ 8) or PBO (n ⫽ 6) BID each nostril ⫻6 wk
`TAAANS 2 ⫻ 55 ␮g sprays each nostril QD (n ⫽
`29); CTZ 10 mg orally QD (n ⫽ 30); BDPANS 50
`␮g spray each nostril QID (n ⫽ 31)
`
`Laliberte et al8
`
`In vivo, 6-month, multicenter, random-
`ized, parallel-group, open study
`
`TAAANS (n ⫽ 21); BDPANS (n ⫽ 26); CTZ
`(n ⫽ 23) ⫻6 mo
`
`McMahon et al25
`
`In vivo, 2-part, randomized, double-blind,
`placebo-controlled, study: part 1, 2-arm,
`2-way crossover, part 2, 3-arm, 2 wk
`
`Part 1: NaCl 0.9% or NaCl 0.9% ⫹ 0.02% PKC 2 ⫻
`100 ␮L per nostril; 1 week between treatments,
`then crossover (n ⫽ 27)
`Part 2: NaCl 0.9% (n ⫽ 20), FPANS (n ⫽ 23), or
`FPANS vehicle (n ⫽ 15), 2 squirts each nostril
`BID ⫻ 2 wk
`
`Storraas et al27
`
`In vivo, 2-part, single-treatment, study:
`part 1, acute BKC exposure; part 2, sus-
`tained BKC exposure
`
`Part 1: 10 min nasal pool exposure NS and NS ⫹
`0.1 mg/mL (n ⫽ 10)
`
`Part 2: 100 ␮L each nostril TID ⫻ 10 d (n ⫽ 12)
`
`Holm et al31
`
`In vivo, double-blind, parallel-group study
`comparing FPANS BID vs placebo.
`Duration of 1 y
`␣2-MG, ␣2-Macroglobulin; BDPANS, beclomethasone dipropionate aqueous nasal spray (BDP 0.2%, sodium citrate 0.038%, citric acid
`monohydrate 0.0195%, chlorocresol 0.01%, sodium chloride 0.9%, BKC 0.01%, polysorbate-80 0.0008%, distilled water q.s. 100 g); BKC,
`benzalkonium chloride; CBF, ciliary beat frequency; DTPA, diethylenetriaminepentaacetic acid; FPANS, fluticasone propionate aqueous nasal
`spray; ICST, indigocarmine saccharine transport time; LM, light microscopy; NS, normal saline (0.9%); PBO, placebo; SCT, saccharine clearance
`time; SEM, scanning electron microscopy; TAAANS, triamcinolone acetonide aqueous nasal spray; TEM, transmission electron microscopy.
`
`FPANS 100 ␮cg BID vs placebo. (n ⫽ 42)
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`Otolaryngology–
`Head and Neck Surgery
`Volume 130 Number 1
`
`Table 1. Continued
`
`Evaluation method(s)
`
`BKC (%)
`
`Results
`
`MARPLE et al 135
`
`LM: epithelium, number of cili-
`ated cells; ciliated cells
`SEM and TEM: ultrastructure
`
`0.02% Monkeys,
`0.01% rats
`
`Evaluate nasal clearance with
`radiolabeled (99Tc-DTPC)
`saccharine nasal spray, 1 h
`after preservative or PBO
`nasal drops
`ICST q 2 wk, before, during,
`and after treatment
`
`ICST, endoscopic evaluation,
`nasal mucosal thickness
`(NMT)
`
`Endoscopic evaluation of nasal
`cavities, biopsies of posterior
`inferior nasal turbinate
`
`0.01%
`
`0.02%
`
`0.02%
`
`0.02%
`
`Part 1: Immediate effect on SCT
`
`0.02%
`
`Part 2: effect before and after
`2 wk exposure, on SCT, CBF,
`acoustic rhinometry (Amin),
`& symptom scores (SS)
`
`Part 1: Nasal pain (0 ⫽ none to
`3 ⫽ several); ␣2-MG; fucose
`
`0.1 mg/mL
`
`Part 2: nasal symptoms (sneezes,
`blockage, rhinorrhea, and pain;
`0 ⫽ none to 3 ⫽ severe); ␣2-
`MG: fucose; histamine chal-
`lenge before and after BKC
`exposure
`
`Nasal biopsies were obtained at
`entry and end of treatment
`period
`
`0.02%
`
`LM: monkeys, no effect; rats, lower incidence of lymphoid
`tissue in upper airway of treated rats
`SEM and TEM: no abnormalities or differences between
`treated and control monkeys and rats
`No significant differences in either CI rate or proportion of
`radiolabeled nasal spray at 10, 20, 30, 60, and 90 min after
`administration with any preservative compared with PBO (P
`⬎ 0.05, for both)
`
`No significant differences between groups; no statistical rela-
`tionship between number of ciliated cells and treatment;
`SEM and TEM showed no BKC effects
`For all ITT treatment groups; no statistically significant differ-
`ence in NMT; no quantitative or qualitative treatment-related
`differences in nasal epithelium; biopsies showed no destruc-
`tion of epithelium; no major or minor endoscopic findings
`Endoscopy: for all treatments, all nasal tissue were still normal
`after 6 mo of therapy LM: no significant difference in ET
`between all 3 treatment groups (P ⬍ 0.06), all showed de-
`creased ET from PT compared with EOT; qualitative an
`LM: no significant difference in ET between all 3 treatment
`groups (P ⫽ 0.06), all showed decreased ET from PT com-
`pared with EOT; qualitative analysis showed no significant
`change in individual biopsies before and after treatment; bi-
`opsies never showed epithelium destruction. Long-term
`Treatment with BKC showed no adverse effects on nasal mu-
`cosa
`Part 1: neither treatment showed a significant difference in
`SCT (P ⬎ 0.05)
`Part 2: no significant differences in measurements (ie, CBF,
`SCT, Amin, SS) between treatments after 2 weeks (P ⬎
`0.053); all treatments showed a significant decrease in CBF
`(P ⱕ 0.013); SCT tended to increase but not significantly (P
`ⱖ 0.20); no evidence of any ciliotoxicity during 2 wk regu-
`lar therapy
`Part 1: pain scores: 0.3 ⫾ 0.2 NS, 1.2 ⫾ 0.2 BKC (P ⬍ 0.01);
`BKC significantly increased fucose secretion (P ⬍ 0.05);
`␣2-MG unaffected
`Part 2: no nasal pain on frequent BKC administration; nasal
`secretion/blockage infrequent; nasal baseline scores 0.4 ⫾
`0.2 before and after BKC (P ⫽ 0.79); histamine increased
`nasal symptoms before and after BKC (P ⬍ 0.01); histamine
`increased ␣2-MG before and after 10 d BKC (P ⬍ 0.01) but
`plasma exudation of ␣2-MG was unaffected. BKC in concen-
`trations for OTC products is not associated with exudative
`hyperresponsiveness or airway inflammation
`Improvement in tissue edema. No detrimental effects to epithe-
`lium, cellular inflammation, or sinusoidal nasal dilation
`
`Beyond the obvious problems posed by com-
`parison of differing in vitro methodologies, other
`problems arise when attempting to predict in vivo
`
`outcomes based on in vitro results.26 Discrepan-
`cies between conclusions derived from in vitro
`and in vivo studies may occur as a result of nu-
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`136 MARPLE et al
`
`Otolaryngology–
`Head and Neck Surgery
`January 2004
`
`Table 2. Summary of studies finding toxic effects associated with benzalkonium chloride (BKC)
`
`Author
`
`Berg et al28
`
`Design
`
`Treatment Materials/Regimen
`
`Two 3 wk animal in vivo
`experiments (E1 and E2)
`
`E1: 10 ␮L right nostril FLANS (n ⫽ 10) or BDPANS (n ⫽ 10)
`or BUDANS-PF (n ⫽ 10); left nostril 10 ␮L PBO (n ⫽ 30)
`E2: 10 ␮l right nostril BDPANS (n ⫽ 10) or BUDANS-PF (n
`⫽ 10); left nostril 10 ␮L PBO (n ⫽ 20) PBO, NaCl 0.9%
`
`Berg et al29
`
`Three in vitro 2-wk experi-
`ments with cultured hu-
`man ciliated epithelium
`exposed to varied concen-
`trations of BKC for 1 to
`30 min/d
`
`Cho et al12
`
`In vivo, placebo-controlled,
`4-wk preclinical study
`
`Undiluted oxymetazoline NS (ONS) and 3%, 10%, and 30%
`diluted ONS in NaCl
`
`80 Sprague-Dawley rats exposed to low and high concentrations
`of preservatives: 0.01% BKC or 0.1% PS (n ⫽ 9); 0.1% BKC
`or 5.0% PS (n ⫽ 9); TAA 0.15% w/0.01% BKC or 0.1% PS
`(n ⫽ 9); TAA 0.15% w/0.1% BKC or 5.0%
`PS (n ⫽ 9); PBO (NS) (n ⫽ 4); 7 ␮L in each nostril BID ⱕ4
`wk
`
`Graf et al9
`
`In vivo, randomized, double-
`blind, parallel-group clini-
`cal study
`
`OMZ 0.5 mg/mL (n ⫽ 10) or OMZ 0.5 mg/mL ⫹ 0.1 mg/mL
`BKC (n ⫽ 10): 0.1 mL each nostril TID ⫻30 d
`
`Graf and
`Hallen10
`
`In vivo, randomized, place-
`bo-controlled, double-
`blind, parallel-grouped,
`clinical study
`
`OMZ 0.5 mg/mL (n ⫽ 10), 0.1 mg/mL BKC (n ⫽ 10), or PBO
`(NS ⫹ Na phosphate ⫹ EDTA) (n ⫽ 10): 0.1 mL each nos-
`tril TID ⫻30 d
`
`Graf et al11
`
`In vivo, randomized, double-
`blind, parallel-grouped,
`clinical study
`
`OMZ 0.5 mg/mL (n ⫽ 17) or OMZ 0.5 mg/mL ⫹ 0.1 mg/mL
`BKC (n ⫽ 18): 0.1 mL each nostril TID ⫻10 d
`
`BDPANS, Beclomethasone dipropionate aqueous nasal spray; BKC, benzalkonium chloride; BTN spray-PF, betamethasone, tramazoline,
`neomycin spray–preservative-free; BUDANS-PF, budesonide aqueous nasal spray–preservative-free; EDTA, ethylenediamine tetraacetic acid;
`FLANS, flunisolide aqueous nasal spray; FPANS, fluticasone propionate aqueous nasal spray; IPM, inverted phase microscopy; LM, light
`microscopy; Na phosphate, sodium phosphate; OMZ, oxymetazoline; PBO, placebo; PS, potassium sorbate; SEM, scanning electron microscope;
`TEM, transmission electron microscope.
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`Otolaryngology–
`Head and Neck Surgery
`Volume 130 Number 1
`
`Table 2. Continued
`
`Evaluation Method(s)
`
`BKC %
`
`Results
`
`MARPLE et al 137
`
`Forty-eight of 50 heads, fixed, de-
`calcified, and sectioned; steroid
`treated right side compared with
`left side PBO control for histo-
`logic changes in nasal mucosa
`
`FLANS 310 ␮g/ml
`(0.031%); BUDANS
`220 ␮g/mL (0.022%)
`
`BUDANS-PF: no histologic difference compared with
`PBO, although both treatments showed frequent
`openings in cilia carpet by goblet cells
`
`FLANS, and BDPANS: morphologic alterations, epi-
`thelium, height reduced with pleomorphism of some
`cells, few cells with cilia; number of goblet cells
`reduced, and no mucus covering epithelium; no
`changes in subepithelium; greatest changes were
`anterior/septum, lesser changes away from vestibu-
`lum. No statistical analyses were performed.
`BKC 0.015% to 0.0015% showed a gradual loss of
`continuous epithelial lining was concentration and
`time dependent. BKC 0.00045% showed no mor-
`phologic changes compared with NaCl control solu-
`tion
`
`BKC: week 1, increased proliferation of intraepithelial
`glands inflammatory cell infiltration regardless of
`TAA; week 4, less histologic changes w/TAA com-
`pared with BKC alone and decreased epithelial
`thickness.
`PS: similar trend in results. Editor’s note states
`study underpowered and SDs too large to “draw sta-
`tistically valid conclusions.”
`After 30 d, O MZ ⫹ BKC showed greater mucosal
`swelling, and stuffiness was greater in PM at week
`4 (P ⬍ 0.05, for both); unpaired t tests showed no
`difference in mucosal swelling between groups at
`any histamine provocation level before or after
`treatment. No differences in nasal symptoms scores
`were found between the 2 groups.
`
`Only BKC group had significantly greater mucosal
`swelling (P ⬍ 0.05, paired t test) at 30 d. However,
`ANOVA showed no significant differences in mu-
`cosal swelling between groups. All groups had in-
`creased reactivity to histamine but BKC and PBO
`were significantly higher at 2 mg/mL concentration
`(P ⬍ 0.05, for both)
`No difference in mucosal swelling between groups
`(unpaired t test). Symptom scores were also very
`similar before and after treatment: 50/49 with BKC
`and 48/51 without BKC
`
`Cultured adenoid tissue from ade-
`noidectomies w/beating, ciliated
`epithelia (288 samples: 8 ⫻ 12/
`experiment); exposed QD ⫻ 14 d
`to undiluted ONS for 1, 3, 10,
`and 30 min each, and diluted
`ONS for 10 min Control, 10 min
`in NaCl (8 groups total)
`Tissue changes evaluated by IPM,
`LM, SEM, and TEM
`Weeks 1, 2, and 4 (n ⫽ 3, each
`Tx): nasal cavities sectioned and
`epithelial tissue examined
`
`Undiluted: 0.15 mg/mL
`(0.015%); 30%: 0.045
`mg/mL (0.0045%);
`10%: 0.015 mg/mL
`(0.0015%); 3%:
`0.0045 mg/mL
`(0.00045%)
`
`0.01% 0.1%
`
`Nasal swelling via rhinostereometry,
`and nasal reactivity via histamine
`challenge with 1.0, 2.0, and 4.0
`mg/mL at baseline and end of
`study Nasal symptoms (ie, dry
`nose, runny nose, irritation, nasal
`bleeding, and/or a cold) and nasal
`stuffiness via VAS (0 clear to 100
`blocked) daily
`Nasal swelling and nasal reactivity
`at baseline and end of study, and
`daily nasal symptoms (see Graf et
`al, 1995)
`
`Nasal swelling (acoustic and stereo-
`metric) and nasal reactivity at
`baseline and end of study and
`daily nasal symptoms (see Graf et
`al, 1995)
`
`0.01%
`
`0.01%
`
`0.01%
`
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`
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`

`138 MARPLE et al
`
`Table 2. Continued
`
`Author
`
`Griffen and
`Cote30
`
`Otolaryngology–
`Head and Neck Surgery
`January 2004
`
`Design
`
`Treatment Materials/Regimen
`
`Experimental in vitro (hu-
`man)
`
`Betamethasone drops
`Betamethasone ⫹ neomycin drops
`BTN spray-PF
`
`Merkus and
`Vande donk3
`
`Experimental in vitro (ani-
`mal)
`
`Various prescription and nonprescription intranasal products
`
`Hallen and
`Graf13
`
`In vivo, randomized, double-
`blind, parallel-grouped,
`clinical study
`
`OMZ 0.5 mg/mL (n ⫽ 10) or OMZ 0.5 mg/mL ⫹ 0.1 mg/mL
`BKC (n ⫽ 9); 0.1 ml each nostril TID ⫻10 d (3 mo earlier,
`same patients previously used same products for 4 wk)
`
`Steinsvag et al16
`
`Experimental in vitro (hu-
`man adenoid tissue)
`
`BDPANS 500 ␮g/mL
`FLANS 250 ␮g/mL
`BUDANS 2 mg/mL
`
`merous protective mechanisms intrinsic to the lo-
`cal nasal environment. Nasal secretions and active
`mucociliary clearance cause varying dilutions of
`preservatives, while simultaneously serving as a
`mechanical barrier to protect ciliated nasal epithe-
`lium from the detrimental effects of substances
`that are introduced into the nose.15,17,24,27 Nasal
`mucus is a complex aqueous mixture of glycop-
`roteins, lipids, salts, and other cellular constituents
`that normally protects nasal epithelia from a wide
`variety of environmental insults. Aside from its
`function as a simple mechanical barrier, nasal
`mucus likely plays an active role through inacti-
`vation of many substances that gain access to the
`nose. This characteristic of nasal mucus has been
`found to adversely affect the absorption and action
`of some intranasal formulations.28 Ainge et al9
`suggested that various proteins contained within
`nasal mucus possess the ability to rapidly inacti-
`vate quaternary ammonium compounds such as
`BKC. In the specific case of quaternary ammo-
`nium compounds, BKC can be inactivated by non-
`ionic surfactants,29 raising the possibility that
`BKC may be neutralized by the surfactant prop-
`erties of nasal mucus.6,28
`Another local factor that might contribute to
`amelioration of the reported in vivo results of
`BKC is the acidic environment of the nasal cavity.
`
`pH plays an important role in the antimicrobial
`activity of weak acids by influencing the nondis-
`sociated fraction of the molecules that are the most
`effective in preservative activity.29 In an in vitro
`study by van de Donk et al,26 the negative effect of
`BKC on ciliary beat frequency was significantly
`attenuated with decreases in pH. Moreover, this
`effect was noted with rather mild reductions of the
`pH from 7.4 to 6.0. Given the fact that the normal
`pH of the nose is slightly acidic, ranging from 5.5
`to 6.0,30 it is reasonable that this factor might
`contribute to the disparity found when comparing
`in vivo and in vitro results.26,31
`It has been proposed that different regions
`within the nasal cavity might be more susceptible
`to the effects of BKC toxicity, due to either con-
`centration of BKC or innate susceptibility to in-
`sult. Such areas within the nasal vestibule would
`include the nasal septum, and anterior aspects of
`the inferior and middle turbinates, which are di-
`rectly challenged by the application of nasal
`sprays. To assess this, Ainge et al9 specifically
`studied histologic specimens obtained from the
`anterior head of the inferior turbinates in primates
`and rats exposed to 28 days of fluticasone dipro-
`pionate or beclomethasone dipropionate, both con-
`taining BKC. No histologic differences were noted
`compared with control animals, with the exception
`
`Downloaded from
`
`oto.sagepub.com
`
` at PENNSYLVANIA STATE UNIV on September 18, 2016
`
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`

`

`Otolaryngology–
`Head and Neck Surgery
`Volume 130 Number 1
`
`Table 2. Continued
`
`MARPLE et al 139
`
`Evaluation Method(s)
`
`BKC %
`
`Results
`
`CBF of human nasal cilia (obtained
`by brush technique) after expo-
`sure to increased dilutions of
`products
`
`CBF of chicken trachea after 60-
`min exposure: rated based on per-
`cent recovery of CBF Cilio-
`friendly, ⱖ75%, cilio-inhibiting,
`25% 75%, cilostatic, ⱕ 25%
`Nasal symptom scores, mucosa
`swelling, mucosa reactivity (see
`Graf studies)
`
`0.006%
`
`0.01%-0.02%
`
`0.01%
`
`CBF, changes in cell morphology
`
`0.031%, 0.022%,
`0.020%
`
`BKC 0.006% ⫹ EDTA 0.1%, and thiomersal 0.005%
`caused ciliostasis; a ⫻25 dilution was not ciliotoxic;
`human nasal cilia may be more sensitive to effects
`of preservatives than animal cilia or human adenoi-
`dal cilia
`Products with BKC had a cilio-inhibiting effect. Prod-
`ucts with 0.02% BKC were often ciliostatic effect
`(no statistical analysis of results)
`
`Symptom scores and nasal reactivity were not statisti-
`cally different between groups, although patients
`treated with OMZ ⫹ BKC had higher symptom
`scores; nasal mucosa swelling was significantly
`higher w/BKC (P ⬎ 0.05) and difference was sig-
`nificant between groups (P ⬎ 0.05)
`Changes in CBF and cell morphology increased w/in-
`creased concentrations of BKC; no statistical analy-
`ses were performed
`
`of a decrease in submucosal lymphoid tissue in the
`treatment groups.
`Based on these considerations, the significant
`differences that are observed when comparing in
`vitro and in vivo data are less confusing. Given the
`protective effects of the barrier action of nasal
`mucus, varying dilution of BKC concentration,
`potential enzymatic degradation of BKC, and pH
`effect on BKC activity, it is reasonable to conceive
`that the protective mechanisms that are intrinsic to
`the nasal environment during in vivo studies can
`compensate for toxic effects observed with BKC
`in some in vitro studies. Quite simply, the end
`result is that the nose provides an environment
`within which nasal epithelial exposure to BKC is
`minimized.
`In preparation of this review, a total of 18
`studies (14 in vivo, 4 in vitro) were identified that
`evaluated short- and long-term clinical exposure
`of concentrations of BKC ranging from 0.00045%
`to 0.1%. Eight of
`these studies,
`including a
`6-month long-term treatment study, demonstrated
`no significant differences, indicating that BKC
`was either harmful to nasal tissue or prone to exac-
`erbate rhinitis medicamentosa. Of the 10 studies that
`concluded that BKC resulted in degenerative
`changes in human nasal epithelia or exacerbated
`rhinitis medicamentosa, only 2 demonstrated statis-
`
`tical significance when treatment differences be-
`tween BKC and placebo or active control groups
`were compared. Both of these studies included the
`use of oxymetazoline, which is associated with rhi-
`nitis medicamentosa. In its present state, the current
`body of literature addressing the issue of BKC safety
`is confusing and logically has led to fueling debate
`regarding its safety. Ultimately, interpretation of the
`information regarding the safety of BKC requires
`aggregate consideration of the entire body of infor-
`mation related to this co