Assessment of corneal epithelial integrity after acute exposure to ocular hypotensive agents preserved with and without benzalkonium chloride

Preservatives and ocular surface disease: A review

Ocular surface disease (OSD) is a complex condition that can cause a range of symptoms (e.g, dryness, irritation, and pain) and can significantly impact the quality of life of affected individuals. Iatrogenic OSD, a common finding in patients with glaucoma who receive chronic therapy with topical ocular antihypertensive drugs containing preservatives such as benzalkonium chloride (BAK), has been linked to damage to the ocular surface barrier, corneal epithelial cells, nerves, conjunctival goblet cells, and trabecular meshwork. Chronic BAK exposure activates inflammatory pathways and worsens symptoms, compromising the success of subsequent filtration surgery in an exposure-dependent manner. In eyes being treated for glaucoma, symptomatic treatment of OSD may provide some relief, but addressing the root cause of the OSD often necessitates reducing or, ideally, eliminating BAK toxicity. Strategies to decrease BAK exposure in patients with glaucoma encompass the use of preservative-free formulations or drugs with alternative and less toxic preservatives such as SofZia®, Polyquad, potassium sorbate, or Purite®. Though the benefits of these alternative preservatives are largely unproven, they might be considered when financial constraints prevent the use of preservative-free versions. For patients receiving multiple topical preserved drugs, the best practice is to switch to nonpreserved equivalents wherever feasible, regardless of OSD severity. Furthermore, nonpharmacological approaches, including laser or incisional procedures, should be considered. This review explores the effects of BAK on the ocular surface and reviews strategies for minimizing or eliminating BAK exposure in patients with glaucoma in order to significantly improve their quality of life and prevent complications associated with chronic exposure to BAK.

Lessons Learned From Ocular Graft versus Host Disease: An Ocular Surface Inflammatory Disease of Known Time of Onset

ABSTRACT

The ocular surface inflammatory disorders (OSIDs) comprise a group of conditions characterized by persistent inflammation of the ocular surface and adnexal tissues. Systemic autoimmune diseases and hypersensitivity reactions cause them, and, if left untreated, can result in severe inflammatory dry eye, corneal damage, and vision loss. Ocular graft-versus-host disease (oGVHD) forms part of the ocular surface inflammatory disease umbrella. It is a condition occurring after allogeneic hematopoietic stem cell or bone marrow transplantation, usually in chronic graft-versus-host disease. oGVHD can virtually affect any ocular adnexal tissue, especially the meibomian glands, and cause persistent inflammation, tissue fibrosis, and subsequent chronic, severe dry eye disease. Among the OSIDs, oGVHD has the particularity that it has a "time zero," meaning we know when the disease started. As such, preclinical models have leveraged this to investigate the molecular mechanisms involved in the damage oGVHD causes to the ocular surface. In oGVHD, establishing a "time zero" allows for predicting the clinical course and establishing adequate treatment. This is also possible because the inflammatory infiltration occurs in ocular surface tissues, which are readily accessible. Using oGVHD, we might be able to understand the immune response mechanisms in other OSIDs better (i.e., Sjögren syndrome, Stevens-Johnson syndrome, among others). This review presents an up-to-date overview of the pathogenesis, clinical presentation, and treatment of oGVHD. In addition, we will discuss the value of the "time zero" concept in the study of oGVHD.

Benzalkonium Chloride-Induced Corneal Epithelial Injury in Rabbit Reduced by Rebamipide

Purpose: We assessed the effect of rebamipide ophthalmic solution on corneal epithelial injury due to benzalkonium chloride (BAK) by fluorescein (FL) staining and corneal resistance (CR). Methods: After determining the absence of corneal epithelial damage by FL and CR, rebamipide ophthalmic solution (50 μL) was instilled five times, each interspaced by 5 min, into one eye of mature New Zealand white rabbits, and likewise physiological saline was instilled into the contralateral eye as the control. After 30 min, eyes were similarly treated with one of the following solutions: BAK solution 0.02%, latanoprost ophthalmic solution (0.02% BAK), or latanoprost ophthalmic solution without BAK. The presence of corneal epithelial damage was quantitated at 10, 30, and 60 min by CR after the last instillation. FL staining was also performed at 60 min after the last instillation. Results: CR ratios (%) at 60 min after the last instillation in rebamipide/BAK and rebamipide/latanoprost (0.02% BAK) groups were significantly increased by 18.3% and 25.6% compared with saline/BAK and saline/latanoprost (0.02% BAK) groups, respectively (P < 0.05). Findings by FL staining were consistent with those by CR; BAK and latanoprost with BAK groups were positive, and eyes with the most severe area and density of corneal epithelial damage (A2D2) were in the saline/BAK group. Conclusion: The rebamipide ophthalmic solution reduces the severity of corneal epithelial injury caused by BAK, an ophthalmic solution preservative.

A new look at the safety and tolerability of prostaglandin analogue eyedrops in glaucoma and ocular hypertension

INTRODUCTION

In the last 25 years, topical prostaglandin analogues (PGAs) have emerged to become first line and first choice therapeutic options in the management of glaucoma and ocular hypertension (OHT). Although the short-term efficacy and safety of PGAs has been extensively investigated, less is known about their long term safety and tolerability. This gap in current knowledge is clinically relevant, because treatment-related adverse events and long-term tolerability issues are key determinants of the overall success of long-term therapy and the final outcome of a lifelong, symptomless disease like glaucoma.

AREAS COVERED

We include selected evidence pertaining to the safety and tolerability of available and emerging PGA formulations. We also outline PGA formulations with different concentrations of the active ingredient, different preservatives, and preservative-free (PF) options.

EXPERT OPINION

Undoubtedly PGAs will continue to play a major role in the medical therapy of glaucoma and OHT. Despite extensive literature and prolonged clinical experience with these agents worldwide, a number of areas that warrant further research have been identified in the present review. Recently launched novel PGAs, or those still in development offer new opportunities and future challenges.

Benzalkonium Chlorides: Uses, Regulatory Status, and Microbial Resistance

Benzalkonium chlorides (BACs) are chemicals with widespread applications due to their broad-spectrum antimicrobial properties against bacteria, fungi, and viruses. This review provides an overview of the market for BACs, as well as regulatory measures and available data on safety, toxicity, and environmental contamination. We focus on the effect of frequent exposure of microbial communities to BACs and the potential for cross-resistant phenotypes to emerge. Toward this goal, we review BAC concentrations in consumer products, their correlation with the emergence of tolerance in microbial populations, and the associated risk potential. Our analysis suggests that the ubiquitous and frequent use of BACs in commercial products can generate selective environments that favor microbial phenotypes potentially cross-resistant to a variety of compounds. An analysis of benefits versus risks should be the guidepost for regulatory actions regarding compounds such as BACs.

Efficacy and safety of extemporaneously prepared miconazole eye drops in Candida albicans-induced keratomycosis

PURPOSE

Extemporaneously prepared miconazole eye drops (EPMD) are used by some eye care practitioners to manage keratomycosis in Ghana. This study therefore aimed to determine the efficacy and safety of EPMD using in vitro and in vivo experimental models.

METHODS

The minimum inhibitory concentration (MIC) of EPMD was determined by the agar-well diffusion method. In vivo, the activity of EPMD on corneal ulcer, neovascularization, clouding, edema, carring and on keratomycotic conjunctivitis and corneal scarring (clinical features) associated with Candida albicans-induced keratomycosis in rabbits was determined by treating them with 0.034-1.08% (weight-in-volume) EPMD for a period of 30 days. The safety of EPMD on the healthy eye was determined by instilling various concentrations into the intact eye of the rabbits.

RESULTS

The MIC of EPMD on Candida albicans was 1.08% (zone of inhibition of 13 mm ± 0.578), which resulted in significantly better improvements (p ≤ 0.001) in clinical findings than eyes treated with sterile water (p > 0.05), and showed no significant difference (p > 0.05) compared to eyes treated with 0.3% fluconazole. There were no visible signs of ocular toxicity on instilling it into healthy eyes of rabbits.

CONCLUSION

The extemporaneously prepared miconazole eye drops are effective and safe to use in keratomycosis.

The Effects of Latanoprost With Benzalkonium Chloride Versus Travoprost With SofZia on the Ocular Surface

PURPOSE

To assess ocular surface changes in participants using latanoprost with benzalkonium chloride (Xalatan) and travoprost with SofZia (Travatan Z).

METHODS

In this prospective, open-label, nonrandomized cohort study, participants were classified into two groups: group 1 (n=28) naive to glaucoma therapy, group 2 (n=27) on previous Xalatan monotherapy in both eyes. Both groups started (or continued) Xalatan in the right eye and Travatan Z in the left eye. Baseline, 1-, and 2-month measurements of tear breakup time (TBUT), corneal staining score, conjunctival staining score, conjunctival hyperemia score, tear production, and intraocular pressure were obtained. The Ocular Surface Disease Index questionnaire measured participants' comfort and dryness symptoms. Medication preference was recorded.

RESULTS

Data were collected from 55 participants. Tear breakup time at baseline and 1-month follow-up in group 1 was significantly longer than that of group 2 (P=0.005). At 2 months, there was no significant difference in TBUT between the two groups (P=0.779). Tear production in group 1 at all three time points was significantly higher than group 2 (P<0.05). Conjunctival staining score at 2 months in group 1 was significantly higher than group 2 (P=0.031). There was no significant difference in other parameters between the groups at any other time point. No significant difference in any parameter was found between Xalatan and Travatan Z (intragroup comparison).

CONCLUSIONS

Significant differences in ocular surface characteristics were detected between groups, but no significant difference was detected between participants treated with Xalatan and Travatan Z.

Ocular Graft-Versus-Host Disease: A Review

Hematopoietic stem cell transplantation is important in the management of several lymphoproliferative and bone marrow disorders. Graft-versus-host disease (GVHD) involves inflammatory manifestations that arise after transplant and can affect many organs. Ocular manifestations of GVHD are common, and eye care providers must understand this disease entity. The ocular surface is most commonly involved, but GVHD can affect all parts of the eye. Ocular GVHD can be relapsing and remitting, can decrease quality of life, and can be challenging to diagnose and adequately treat. The diagnostic criteria for and grading of ocular GVHD continue to evolve. This review aims to summarize current definitions, clinical findings, diagnostic criteria, and management of ocular GVHD. The care of patients with ocular GVHD requires a multidisciplinary approach.

Comparison of the ocular surface changes following the use of two different prostaglandin F2α analogues containing benzalkonium chloride or polyquad in rabbit eyes

OBJECTIVE

The aim of this study is to compare the effect of prostaglandin analogues preserved with either 0.015% or 0.001% benzalkoium chloride (BAK); or 0.001% polyquad (PQ) on the ocular surface of rabbit eyes.

METHODS

Forty white rabbits were randomized to receive four-times daily instillation of either 0.0015% tafluprost (TF) preserved with 0.001% BAK (TF-BAK); 0.004% travoprost (TR) with 0.015% BAK (TR-BAK) or 0.001% PQ (TR-PQ); or preservative-free artificial tears in one eye for a 4-week period. Tear samples collected from the 40 rabbits were analyzed by enzyme-linked immunosorbent assays (ELISA) to identify the presence of inflammatory cytokines: interleukin (IL)-1β and IL-6 on day 14. Subsequently, harvested cornea and bulbar conjunctiva were evaluated using light and transmission electron microscopy (TEM).

RESULTS

IL-6 was significantly increased in TF-BAK and TR-BAK groups compared to controls and TR-PQ group (p = 0.005); however, IL-1β level was not significantly different among four groups (p = 0.360). Rabbits treated with TR-BAK showed decreased goblet cell density of bulbar conjunctiva and increased pyknotic change and vacuolization of corneal epithelial cells on light microscopy; similar change occurred but was less severe in TF-BAK group. The TR-PQ group showed similar results as the controls. The destruction of the microvillar architecture of bulbar conjunctiva and cornea was most prominent in the TR-BAK group.

CONCLUSIONS

Preservatives included in the anti-glaucoma eye-drops showed different ocular surface changes according to the concentration and type in the rabbits. Prostaglandin analogues preserved with higher level of BAK may cause more harmful effects on the ocular surface than PQ-preserved medications.

Mechanisms of benzalkonium chloride toxicity in a human trabecular meshwork cell line and the protective role of preservative-free tafluprost

BACKGROUND

Benzalkonium chloride (BAK) is a controversial ophthalmic preservative because of its prominent side-effect profile. In this study, we examined the mechanism of BAK toxicity in human trabecular meshwork cells (HTMC) and compared the effects of BAK with tafluprost free acid, which is an active form of tafluprost commercially available in a preservative-free formulation.

METHODS

Primary HTMC were treated with different BAK concentrations over various exposure times. Cell viability was quantified using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenol tetrazolium bromide assay, and apoptosis was measured by enzyme-linked immunosorbent assay. The cell viability of primary HTMC exposed to various concentrations and times of tafluprost free acid was also determined. Cells were treated with BAK and tafluprost free acid for 30 min at 37°C, and cell viability was again assessed. The effect of BAK on the gap junction protein Connexin-43 (Cx43) expression was subsequently examined.

RESULTS

BAK treatment resulted in a dose- and time-dependent decline in cell viability. Apoptosis increased following BAK treatment. Tafluprost-free acid treatment did not significantly affect cell viability. Tafluprost co-treatment with BAK resulted in an increase in cell viability as compared with BAK treatment alone. BAK treatment upregulated Cx43 expression in HTMC.

CONCLUSIONS

These results demonstrate that BAK is harmful to the health of cultured HTMC. Tafluprost is both safe and cytoprotective against BAK for these HTMC. The effect of tafluprost on the gap junctions of the HTM should be further investigated.

Bimatoprost 0.01% vs bimatoprost 0.03%: a 12-month prospective trial of clinical and in vivo confocal microscopy in glaucoma patients

PURPOSE

To evaluate the safety of two commercially available formulations of bimatoprost eye drops: 0.03 and 0.01% ophthalmic solutions.

METHODS

This was a randomized, prospective, parallel-group, open-label, cohort study. A total of 60 glaucoma patients (60 eyes) under bimatoprost 0.03% monotherapy since at least 1 year were enrolled. Selected patients were randomized to receive a single drop of bimatoprost 0.01% (n=30) or bimatoprost 0.03% (n=30) ophthalmic solutions for 12 months. Statistical analysis was performed using paired t-test and repeated measures ANOVA test.

RESULTS

Global clinical score (the sum of pruritus, stinging/burning, blurred vision, sticky eye sensation, eye dryness sensation, and foreign body sensation) significantly decreased in the bimatoprost 0.01% group from baseline 4.7 ± 3.8 to 2.9 ± 2.3 (P < 0.001) and 2.5 ± 2.0 (P < 0.001) at 6-month and 12-month follow-ups, respectively. Comparison between groups showed differences at both follow-up visits (P = 0.003 and P < 0.001, respectively). In vivo confocal microscopy revealed a significant increase in goblet cell density in the bimatoprost 0.01% group compared with the bimatoprost 0.03% group (P<0.001 at both follow-up visits). All functional parameters and conjunctival hyperemia improved in the bimatoprost 0.01% group at each follow-up visit (P < 0.05) and in comparison with bimatoprost 0.03% (P < 0.05).

CONCLUSION

The results of this trial suggest that bimatoprost 0.01% eye drops seem to decrease the ocular discomfort with respect to bimatoprost 0.03% eye drops.

Corneal epithelial cell viability following exposure to ophthalmic solutions containing preservatives and/or antihypertensive agents

INTRODUCTION

This in-vitro study compared the toxicity of bimatoprost 0.01% containing benzalkonium chloride (BAK) 0.02% with other commercial BAK-free or BAK-containing prostaglandin analogs.

METHODS

Six test solutions were evaluated: travoprost 0.004% with polyquaternium-1 0.001% (PQ), PQ, bimatoprost 0.01% with BAK 0.02%, latanoprost 0.005% with BAK 0.02%, tafluprost 0.0015% preservative free (PF), and BAK 0.02%. Phosphate-buffered saline (PBS) was the live control and 70% methanol was the dead control. Confluent human corneal epithelial cells were incubated with test solutions (diluted 1:5 or 1:10 with PBS) or control solutions for 10 or 25 min, after which cells were fluorescently labeled to distinguish live and dead cells. Data were expressed as a percentage of PBS live-cell fluorescence for automated readouts. Live and dead cells were manually counted for numeric analyses.

RESULTS

For 1:5 and 1:10 dilutions using automated readout, cells exposed to bimatoprost with BAK, latanoprost with BAK, and BAK alone demonstrated significant reductions in the live cell signal compared with PBS, travoprost with PQ, and PQ alone (all P < 0.001). They also demonstrated significantly greater toxicity than tafluprost PF for 1:5 dilutions (all P < 0.001) and 1:10 dilutions (P ≤ 0.02), except for 1:10-diluted bimatoprost with BAK (P = 0.41). For 1:5 dilutions using manual cell count, cells exposed to bimatoprost with BAK demonstrated significant reductions in the percentage of live cells compared with PBS (P = 0.02). For 1:10 dilutions using manual cell count, cells exposed to bimatoprost with BAK, latanoprost with BAK, and BAK alone demonstrated significantly greater toxicity than PBS, travoprost with PQ, PQ alone, and tafluprost PF (all P ≤ 0.03). No significant differences were observed among PBS, travoprost with PQ, and PQ alone under any test conditions (P ≤ 0.63).

CONCLUSION

This study demonstrated that BAKcontaining solutions, including bimatoprost 0.01% with BAK, were toxic to human corneal epithelial cells, whereas BAK-free solutions showed little to no evidence of toxicity.

Effects of preservative-free tafluprost on tear film osmolarity, tolerability, and intraocular pressure in previously treated patients with open-angle glaucoma

Purpose

To compare the effects on tolerability, tear osmolarity, and intraocular pressure (IOP)-lowering effect of switching from benzalkonium chloride (BAK) containing prostaglandin analog (PGA) latanoprost to preservative-free tafluprost.

Patients and methods

Thirty patients with open-angle glaucoma (N = 60 eyes), 26 women (87%) and four men (13%) aged 64.1 (SD 14.1) years, showing abnormal values of tear osmolarity, corneal fluorescein staining, tear film break-up time (TBUT), or subjective discomfort with current latanoprost treatment were included. After tear osmolarity (TearLab™ Osmolarity System), TBUT, corneal fluorescein staining, and baseline IOP (Goldmann tonometer) measurements and the completion of Ocular Surface Disease Index and Ocular Surface Symptoms in Glaucoma Scale questionnaires, patients were assigned to preservative-free tafluprost treatment. Measurements were repeated 2, 6 and 12 weeks after change of medication.

Results

No statistically significant differences in IOP were observed 2, 6, and 12 weeks after switching to preservative-free tafluprost. Mean IOP at baseline was 16.4 mmHg (SD 2.9), after 2 weeks 16.2 mmHg (2.8), after 6 weeks 16.2 (2.6), and after 12 weeks 16.3 mmHg (2.3). Mean tear osmolarity decreased significantly from 315.7 mOsm/L (SD 15.1) at baseline to 308.0 ± 14.4 mOsm/L (P = 0.002), 301.7 ± 14.5 mOsm/L (P < 0.001), and 302.0 ± 9.9 mOsm/L (P < 0.001) 2, 6, and 12 weeks after changing medication to preservative-free tafluprost, respectively. Tear osmolarity was lower in 37 eyes (61.7%) after 2 weeks, in 46 eyes (76.7%) after 6 weeks, and in 49 eyes (81.7%) after 12 weeks (P < 0.005; t-test). At baseline corneal fluorescein staining was observed in 43 eyes (71.7%), after 2 weeks in 34 eyes (56.7%), after 6 weeks in 12 eyes (20.0%), and after 12 weeks in 7 eyes (11.7%) (P < 0.005; McNemar test). Mean TBUT increased from 3.7 seconds (SD 1.1) at baseline to 4.1 seconds (SD 1.0) at week 2, 5.2 seconds (SD 1.5) at week 6, and 6.5 seconds (SD 1.5) at week 12 (P < 0.001; t-test). The number of patients expressing discomfort with latanoprost diminished from 30 (100%) at baseline, to 19 (63.3%) after week 2, and to 11 (36.6%) (P < 0.05; McNemar test) after 12 weeks.

Conclusion

Preservative-free tafluprost is better tolerated than BAK-containing latanoprost, showing lower tear osmolarity levels while maintaining effective IOP control.

Benzalkonium chloride in glaucoma medications

Benzalkonium chloride (BAK) is the preservative used most commonly in eye drops. Although it is effective as an antimicrobial and antifungal agent, both in vitro and in vivo studies have demonstrated adverse effects on surface epithelial cell populations. This is of particular concern with regard to topical medications used over long periods for chronic conditions, such as glaucoma. Newer non-BAK-containing drops are becoming increasingly available, providing an alternative for patients needing long-term eye drop therapy.

Preservative use in topical glaucoma medications

Benzalkonium chloride (BAK) is the principal preservative employed in topical ocular hypotensive medications, although alternative compounds recently have begun to be employed or examined. Individual clinical trials have shown that exposure to BAK concentrations contained in ophthalmic solutions does not produce adverse sequelae in the majority of glaucoma patients, but concerns continue with regard to its long-term use. These concerns have resulted from an extensive research effort, including preclinical studies with in vitro and in vivo models, as well as recent clinical investigations dedicated specifically to this issue. The aim of this systematic literature review of both preclinical and clinical data was to determine the relevance of these findings to clinical practice. Most preclinical studies reported negative effects of BAK exposure, but with few exceptions, BAK concentrations and exposure times greatly exceeded those likely to be experienced by patients, given the normal physiological dilution by the tear film. In addition, consistent evidence of BAK-related toxicity did not emerge from our review of dedicated clinical investigations. Thus, taken together, current evidence supports the safety of BAK for most glaucoma patients, although subpopulations with abnormal tearing may benefit from alternative preservative compounds or preservative-free formulations. Further studies to identify these populations are needed.

Ophthalmic preservatives: focus on polyquaternium-1

INTRODUCTION

Ophthalmic preservatives, such as polyquaternium-1 (PQ-1), are critical for the inhibition of growth of microbial contaminants in multi-dose bottles of topical medications. These antimicrobial agents must have a high efficacy against pathogenic organisms, while maintaining a favorable tolerability and safety profile.

AREAS COVERED

This review focuses on the ophthalmic preservative PQ-1. For comparison purposes, the most commonly used preservative, benzalkonium chloride (BAK), is also discussed. This survey focuses primarily on data collected during the past 10 years.

EXPERT OPINION

Effective drug delivery requires more than just an active ingredient that achieves its desired biological effect on end-target tissues. In addition, drugs must be stable in the containers that they are stored in, and must possess minimal undesired local and systemic side effects that can cause patients to decrease their adherence. In addressing these concerns, specifically in topical ophthalmic drops, one must take into account the active ingredients, vehicle components and preservatives. Medications with fewer adverse effects may lead to enhanced adherence to therapy; therefore, the induction of such adverse outcomes must be considered by physicians when treating patients with chronic ocular disease. Although BAK will continue to be used in ophthalmic medications, due to its familiarity and compatibility with a broad range of topical ocular formulations, PQ-1 is certainly a viable alternative in the preservative formulary armamentarium.

Travoprost 0.004%/timolol 0.5%-fixed combination with and without benzalkonium chloride: a prospective, randomized, doubled-masked comparison of safety and efficacy

PURPOSE

The purpose of this study is to compare the safety and intraocular pressure (IOP)-lowering efficacy of travoprost/timolol in a benzalkonium chloride (BAK)-free fixed combination preserved with polyquaternium-1 (TRA/TIM BAK-free), with travoprost/timolol-fixed combination preserved with BAK (TRA/TIM), in patients with open-angle glaucoma or ocular hypertension.

METHODS

In this prospective randomized controlled trial, subjects with IOP of at least 22  mm Hg in one or both eyes at 0900  h, and IOP of at least 21  mm Hg in one or both eyes at 1100  h and 1600  h at two eligibility visits were randomly assigned to receive either TRA/TIM BAK-free (n=195) or TRA/TIM (n=193), dosed once daily in the morning (0900  h) for 6 weeks. IOP was assessed at 0900  h, 1100  h, and 1600  h at each scheduled visit (baseline, 2 and 6 weeks after randomization).

RESULTS

Mean IOP reduction across all visits and time points was 8.0  mm Hg in the TRA/TIM BAK-free group and 8.4  mm Hg in the TRA/TIM group (P=0.0943). The difference in mean IOP between groups ranged from 0.2 to 0.7  mm Hg across visits and time points, with a mean pooled difference of 0.4  mm Hg (95% CI: -0.1 to 0.8), demonstrating equivalence of the two formulations. The most common drug-related adverse event was hyperemia of the eye (ocular hyperemia and conjunctival hyperemia combined), occurring in 11.8% of the TRA/TIM BAK-free group and 13.0% of the TRA/TIM group.

CONCLUSION

Travoprost/timolol BAK-free demonstrated equivalence to travoprost/timolol preserved with BAK in efficacy. No clinically relevant differences in the safety profiles of travoprost/timolol BAK-free and travoprost/timolol preserved with BAK were identified.

Incidence of new coding for dry eye and ocular infection in open-angle glaucoma and ocular hypertension patients treated with prostaglandin analogs: retrospective analysis of three medical/pharmacy claims databases

Background

To investigate the clinical relevance of two different preservative formulations, we compared 1-year incidence rates of additional coding of dry eye, ocular infection, or ocular surface disease (either dry eye or ocular infection) in open-angle glaucoma and ocular hypertension patients newly treated with latanoprost with benzalkonium chloride (BAK) or with travoprost-Z with SofZia^®.

Methods

This was a retrospective study of three U.S.-based patient-centric medical/pharmacy claims databases (MedStat, PharMetrics, i3-Ingenix). Patients were eligible if they filled a prescription for latanoprost or travoprost-Z between October 2006 and Q2 2008 (prescription date = index date) AND were continuously enrolled 6 months prior through 12 months after the index date AND had any open-angle glaucoma or ocular hypertension diagnosis within 90 days prior to the index date AND did not have an ocular surface disease diagnosis during the 180 days prior to the index date AND if they had not had a prescription for the index agent in the 180 days prior to the index date. Time to incidence of new coding for ocular surface disease in the first year post-index was estimated with a composite endpoint: diagnosis of dry eye or ocular infection by ICD-9-CM or Current Procedural Terminology code OR by prescription for cyclosporine ophthalmic emulsion or ocular antibiotics.

Results

In all, 15,933 patients were treated with latanoprost and 7670 with travoprost-Z. Over 1 year, 4.3% of latanoprost and 4.5% of travoprost-Z patients were identified with dry eye (p = 0.28), and 10.9% and 11.1%, respectively, were identified with an ocular infection (p = 0.79). The 1-year incidence of new coding for ocular surface disease also was similar across treatments (13.9% vs 14.3%, respectively; p = 0.48).

Conclusions

The retrospective analysis of three large prescription databases revealed that open-angle glaucoma and ocular hypertension patients newly treated with latanoprost preserved with BAK or travoprost-Z preserved with SofZia did not differ statistically in rates of dry eye, ocular infection, or ocular surface disease (either dry eye or ocular infection) during the first year post-index. Claims-based analyses are limited by nonrandomization and the inability to account for over-the-counter use or samples.

A multicenter, retrospective chart review study comparing index therapy change rates in open-angle glaucoma or ocular hypertension patients newly treated with latanoprost or travoprost-Z monotherapy

BACKGROUND

Because latanoprost and the original formulation of travoprost that included benzalkonium chloride (BAK) have been shown to be similar with regard to tolerability, we compared initial topical intraocular pressure (IOP)-lowering medication change rates in patients newly treated with latanoprost or travoprost-Z monotherapy.

METHODS

At 14 clinical practice sites, medical records were abstracted for patients with a diagnosis of open-angle glaucoma or ocular hypertension and who were ≥40 years of age, had a baseline and at least one follow-up visit, and had no prior history of ocular prostaglandin use. Data regarding demographics, ocular/systemic medical histories, clinical variables, therapy initiations and reasons for changes, adverse events, and resource utilization were recorded from randomly chosen eligible charts. Primary outcomes were rates of and reasons for changing from the initial therapy within six months and across the full study period (1000 days).

RESULTS

Data from 900 medical charts (latanoprost, 632; travoprost-Z, 268) were included. For both cohorts, average follow-up was >1 year. Cohorts were similar with regard to age (median ~67 years), gender distribution (>50% female), and diagnosis (~80% with open-angle glaucoma). Within six months, rates of index therapy change for latanoprost versus travoprost-Z were 21.2% (134/632) and 28.7% (77/268), respectively (p = 0.0148); across the full study period, rates were 34.5% (218/632) and 45.2% (121/268), respectively (p = 0.0026). Among those who changed their index therapy, insufficient IOP control was the most commonly reported reason followed by adverse events; hyperemia was the most commonly reported adverse event at index therapy change.

CONCLUSIONS

In this "real world" study of changes in therapy in patients prescribed initial monotherapy with latanoprost with BAK or travoprost-Z with SofZia, medication changes were common in both treatment groups but statistically significantly more frequent with travoprost-Z.

Effects of benzalkonium chloride- and polyquad-preserved combination glaucoma medications on cultured human ocular surface cells

INTRODUCTION

The aim of this study is to investigate potential adverse effects of fixed combination glaucoma medications preserved with either benzalkonium chloride (BAK) or Polyquad® (PQ; Alcon Research Ltd., Fort Worth, TX, USA) on cultured ocular epithelial cells.

METHODS

Confluent cultures of human cornea and conjunctival cell lines were exposed for 25 minutes to different glaucoma medications as well as a range of concentrations of BAK (0.001%-0.050%). Balanced salt solution was used as the "live" control and a solution containing 70% methanol and 0.2% saponin was used as a "dead" control. The number of dead and live cells were determined via ethidium homodimer (Eth-1) and calcein acetoxymethyl ester (AM) fluorescence, respectively.

RESULTS

The toxicity of the prostaglandin analog with beta-blocker timolol fixed-combination formulations preserved with BAK was different from that observed in the respective BAK concentrations. Travoprost plus timolol fixed combination with BAK performed better than its respective BAK concentration alone, while the latanoprost plus timolol fixed combination performed worse than its respective BAK concentration. Travoprost plus timolol fixed combination preserved with PQ had greater corneal and conjunctival cell survival than either the travoprost plus timolol fixed combination preserved with BAK or the latanoprost plus timolol fixed combination.

CONCLUSION

Ocular surface side effects have previously been demonstrated with chronic, long-term exposure to intraocular-pressure-lowering medications containing the common preservative BAK. BAK alone has significant in-vitro cytotoxicity to cultured ocular epithelial cells. Substitution of BAK with PQ resulted in significantly higher percentages of live conjunctival and corneal cells. Further studies are needed to understand the clinical implications of these findings.

Efficacy, safety, and improved tolerability of travoprost BAK-free ophthalmic solution compared with prior prostaglandin therapy

Purpose

To evaluate the efficacy, safety and tolerability of changing to travoprost BAK-free from prior prostaglandin therapy in patients with primary open-angle glaucoma or ocular hypertension.

Design

Prospective, multi-center, historical control study.

Methods

Patients treated with latanoprost or bimatoprost who needed alternative therapy due to tolerability issues were enrolled. Patients were surveyed using the Ocular Surface Disease Index (OSDI) to evaluate OSD symptoms prior to changing to travoprost BAK-free dosed once every evening. Patients were re-evaluated 3 months later.

Results

In 691 patients, travoprost BAK-free demonstrated improved mean OSDI scores compared to either latanoprost or bimatoprost (p < 0.0001). Patients having any baseline OSD symptoms (n = 235) demonstrated significant improvement after switching to travoprost BAK-free (p < 0.0001). In 70.2% of these patients, symptoms were reduced in severity by at least 1 level. After changing medications to travoprost BAK-free, mean intraocular pressure (IOP) was significantly decreased (p < 0.0001). Overall, 72.4% preferred travoprost BAK-free (p < 0.0001, travoprost BAK-free vs prior therapy). Travoprost BAK-free demonstrated less conjunctival hyperemia than either prior therapy (p < 0.0001).

Conclusions

Patients previously treated with a BAK-preserved prostaglandin analog who are changed to travoprost BAK-free have clinically and statistically significant improvement in their OSD symptoms, decreased hyperemia, and equal or better IOP control.

A randomized, controlled comparison of macroscopic conjunctival hyperemia in patients treated with bimatoprost 0.01% or vehicle who were previously controlled on latanoprost

Purpose

To evaluate conjunctival hyperemia associated with bimatoprost 0.01% treatment in patients who replace latanoprost 0.005% with bimatoprost 0.01%.

Methods

Randomized, double-masked, vehicle-controlled, multicenter study of patients with ocular hypertension or glaucoma whose intraocular pressure (IOP) was adequately controlled on latanoprost monotherapy. At baseline, patients discontinued latanoprost and were randomized to treatment with once-daily bimatoprost 0.01% (n = 151) or vehicle (n = 71). The primary endpoint was the peak change in macroscopic hyperemia (conjunctival hyperemia evaluated by gross visual inspection) from baseline to month 1.

Results

Bimatoprost 0.01% was noninferior to vehicle in the mean [standard deviation] peak change from baseline macroscopic hyperemia at month 1 (0.18 [0.46] in the bimatoprost 0.01% group vs 0.02 [0.32] in the vehicle group, P = 0.009). The between-group difference was 0.15 (95% confidence interval [CI]: 0.04, 0.26), which was within the predefined margin for noninferiority of 0.5 on a hyperemia grading scale of 0 to +3. There were no statistically significant between-group differences in the percentage of patients with a ≥1-grade increase in macroscopic hyperemia from baseline. Mean IOP was decreased from baseline (−0.7 to −1.3 mm Hg) in the bimatoprost 0.01% group (P ≤ 0.002) and was increased from baseline (+3.3 to +3.6 mm Hg) in the vehicle group (P < 0.001) at month 1. There were no statistically significant between-group differences in adverse events.

Conclusions

Bimatoprost 0.01% was noninferior to vehicle with respect to conjunctival hyperemia in this study population. Replacement of latanoprost with bimatoprost 0.01% in patients with ocular hypertension or glaucoma can result in additional IOP reduction without clinically important hyperemia.

The Role of Benzalkonium Chloride in the Occurrence of Punctate Keratitis: A Meta-Analysis of Randomized, Controlled Clinical Trials

Background:

Benzalkonium chloride (BAK), the most commonly used preservative in topical ophthalmic solutions, has undergone considerable criticism in recent years, principally based on in vitro and in vivo studies. Relevance to the clinical setting has not been confirmed.

Objective:

To determine whether administration of twice the amount of BAK was associated with an increased incidence of punctate keratitis in long-term, double-masked trials comparing latanoprost ophthalmic solution and vehicle with timolol ophthalmic solution in patients with glaucoma or ocular hypertension.

Methods:

A meta-analysis of the double-masked phases of 7 prospective, controlled clinical trials compared the incidence of punctate keratitis among patients assigned to treatment with latanoprost or timolol. In all studies, the amount of BAK administered daily in the latanoprost arms was approximately twice the amount used in the timolol arms. All reports of punctate keratitis either as a finding or an adverse event were included. A fixed-effect model was used because the heterogeneity was small and not statistically significant. Sensitivity analyses were conducted. Funnel plots were provided to address potential publication bias.

Results:

Of the 1694 patients enrolled in the double-masked portion of the trials (latanoprost, n = 892; timolol, n = 802), the overall incidence of punctate keratitis was 6.3% (106/1694). The incidence in latanoprost-treated patients was 6.5% and in timolol-treated patients was 6.0%. The risk difference for punctate keratitis of latanoprost versus timolol was 0.005 (95% CI –0.011 to 0.020; p = 0.574), and the risk ratio of latanoprost versus timolol was 1.084 (95% CI 0.739 to 1.589; p = 0.680).

Conclusions:

These results indicate that BAK does not produce significant corneal toxicity in the vast majority of patients with glaucoma or ocular hypertension at the concentrations used in these studies.

Ocular surface disease in patients with glaucoma or ocular hypertension treated with either BAK-preserved latanoprost or BAK-free travoprost

Purpose

The preservative benzalkonium chloride (BAK) may adversely affect ocular surface health. This study evaluated symptoms of ocular surface disease (OSD) in patients previously treated with a BAK-preserved therapy to lower their intraocular pressure, who either continued that therapy or switched to a BAK-free therapy.

Methods

Eligible adult patients with ocular hypertension or open-angle glaucoma that had been controlled with BAK-preserved latanoprost 0.005% monotherapy (Xalatan^®) for at least one month and had a score of ≥ 13 (0 = none, 100 = most severe) on the Ocular Surface Disease Index (OSDI) questionnaire were entered into this prospective, double-masked, randomized, active-controlled, multicenter trial. By random assignment, patients either continued with BAK-preserved latanoprost 0.005% or transitioned to BAK-free travoprost 0.004% (Travatan Z^® ophthalmic solution). OSDI scores were assessed again after six and 12 weeks.

Results

For the 678 evaluable patients, mean change in OSDI score from baseline to week 12 favored the travoprost 0.004% BAK-free group, but was not statistically different between groups (P = 0.10). When patients with mild OSD at baseline were assessed after 12 weeks, the mean OSDI score was significantly lower (P = 0.04) in the BAK-free travoprost 0.004% group (score = 11.6 ± 10.8 units) than in the BAK-preserved latanoprost 0.005% group (score = 14.4 ± 11.9 units), and a significantly larger percentage (P < 0.01) improved to normal OSDI scores in the BAK-free travoprost 0.004% group (62.9% of group) than in the BAK-preserved latanoprost 0.005% group (47.0% of group). Patients pretreated with BAK-preserved latanoprost 0.005% for >24 months were significantly more likely (P = 0.03) to improve to a normal OSDI score after 12 weeks if they were switched to BAK-free travoprost 0.004% (47.9% of group) than if they remained on BAK-preserved latanoprost 0.005% (33.9% of group).

Conclusions

Switching from BAK-preserved latanoprost 0.005% to BAK-free travoprost 0.004% yielded significant improvements in symptoms of OSD in patients with glaucoma or ocular hypertension.

Effects of benzalkonium chloride-preserved, polyquad-preserved, and sofZia-preserved topical glaucoma medications on human ocular epithelial cells

INTRODUCTION|: To investigate potentially adverse effects of different topical glaucoma medications and preservatives on cultured ocular epithelial cells. METHODS|: Confluent cultures of human corneal (10.014 pRSV-T) and conjunctival cells (1-5c-4) were assayed with 100 μL of different glaucoma medications for 25 minutes at 37°C and 5% CO₂. We also tested the preservative sofZia® (Alcon Laboratories, Fort Worth, TX, USA), as well as a range of concentrations of the preservative benzalkonium chloride (BAK; 0.001% to 0.050%). Balanced salt solution was used as the "live" control and a solution containing 70% methanol and 0.2% saponin was used as a "dead" control. The LIVE/DEAD viability/cytotoxicity kit (Invitrogen, Carlsbad, CA, USA) was used to determine the percentage of dead and live cells via ethidium homodimer and calcein fluorescence, respectively. RESULTS|: The toxicity of the prostaglandin analogs latanoprost, tafluprost and travoprost preserved with BAK was similar to the toxicity observed in their respective BAK concentrations. The prostaglandin analog travoprost (0.004%) preserved with the oxidizing preservative sofZia had much greater corneal and conjunctival cell survival than travoprost preserved with BAK. Travoprost (0.004%) containing polyquad also performed statistically better than its BAK-preserved formulation. CONCLUSION|: Ocular surface side effects have previously been demonstrated with chronic, long-term exposure to intraocular pressure-lowering medications containing the common preservative BAK. BAK alone has significant in-vitro cytotoxicity to cultured ocular epithelial cells. Substitution of BAK with polyquad or sofZia resulted in significantly higher percentages of live conjunctival and corneal cells. Further studies are needed to understand the- clinical implications of these findings.

Handling test of eye drop dispenser--comparison of unit-dose pipettes with conventional eye drop bottles

PURPOSE

The aims of this study were to investigate how elderly people handle single-use eye drop dispensers (unit-dose pipettes) and to compare the performance with conventional eye drop bottles.

METHODS

In this open-label study, the handling of unit-dose pipettes and conventional eye drop bottles was compared in 41 elderly people who had little or no prior regular use of eye drop dispensers. The participants tested both types of dispenser once, and the following 7 variables were studied: ease/difficulty of opening the dispenser; influence of the size for handling of the dispenser; influence of the shape for handling of the dispenser; observation of the contents in the dispenser; the feeling of the dispenser in the hand; ease/difficulty of drop instillation on the eye from the dispenser; and overall performance of the eye drop dispenser. The dispensers contained isotonic saline, and a visual analog scale was used for assessment of each of the above variables.

RESULTS

The mean age of the participants was 73 years. A statistically significant difference in favor of the unit-dose pipettes was found with respect to observation of the contents in the dispenser, ease of administration, and the overall performance. Women regarded the unit-dose pipettes generally better than the bottles, but such a difference was not seen in men.

CONCLUSIONS

The study participants managed the unit-dose pipettes at least as well as the conventional eye drop bottles. If anything, the unit-dose pipettes appeared to be easier to use.

Efficacy and patient tolerability of travoprost BAK-free solution in patients with open-angle glaucoma and ocular hypertension

The medical treatment of glaucoma has evolved significantly over the past several decades. The main driving forces behind this evolution are the safety profiles and efficacy of these medications. Prostaglandin (PG) analogues are shown to be superior to older drugs in both efficacy and tolerability. Though there are much fewer side effects that manifest after using PG analogues, the adherence and compliance to medication regimens are surprisingly lower than expected. A commonly sited reason is the ocular irritation and inflammation with these medications. Much of this inflammation can be attributed to the preservative, benzalkonium chloride (BAK). The chronic clinical and subclinical inflammation becomes increasingly detrimental when filtration surgery fails from bleb fibrosis secondary to this hypercellularity. A BAK-free formulation of a PG analogues recently became available. BAK-free travoprost is reviewed here. It has demonstrated equal efficacy and less ocular surface toxicity than its preserved counterparts. It is expected to serve as an instrumental resource in managing ocular hypertension and glaucoma in patients who demonstrate significant sensitivity to BAK. More randomized, controlled, double-blind studies are encouraged to evaluate its improved safety and tolerability.

In vivo comparative study of ocular vasodilation, a relative indicator of hyperemia, in guinea pigs following treatment with bimatoprost ophthalmic solutions 0.01% and 0.03%

Objective:

The objective of this in vivo study was to compare the incidence of vasodilation in guinea pigs following topical administration of bimatoprost ophthalmic solutions 0.01% and 0.03%.

Methods:

The study comprised 20 guinea pigs assigned to 2 treatment groups (10 per treatment group) to receive either bimatoprost 0.01% or bimatoprost 0.03%. Animals were hand-held under 2.75 × magnification to score ocular vasodilation (a measure of hyperemia), using a scoring system developed at Alcon Research, Ltd. Following baseline ocular scoring, each animal received a 30 μL dose to the left eye of either bimatoprost 0.01% (3 μg) or bimatoprost 0.03% (9 μg). Vasodilation was again scored at 1, 2, 3, 4, 5 and 6 hours after dosing. Incidence of vasodilation was calculated as the percent of total eyes in each 2-hour time interval with scores ≥2.

Results:

The incidence of vasodilation was higher in the bimatoprost 0.01% treatment group (range, 45.0% to 60.0%) than the bimatoprost 0.03% treatment group (range, 30.0% to 52.2%) at all post-dosing time points.

Conclusion:

The 2 bimatoprost formulations elicited ocular vasodilation of long duration (>6 hours) in the guinea pig model, with the bimatoprost 0.01% treatment group showing a higher incidence of ocular vasodilation than the bimatoprost 0.03% treatment group. Further clinical studies would be needed to determine whether the higher incidence of vasodilation may also be attributed to the increased BAK concentration in the bimatoprost 0.01% formulation.

First-year treatment costs among new initiators of topical prostaglandin analogs: pooled results

Objective:

To estimate first-year treatment costs among new initiators of topical prostaglandin analogs in a managed care population.

Research design and methods:

A model was developed to estimate first-year medical costs. Model inputs were based on weighted results from three previous studies. Treatment patterns were derived from a claims database analysis. Published studies were used to estimate visit-related resource use. Costs were obtained from standard sources.

Results:

Across studies, 27,809 patients met study criteria, 44.2% of whom remained on their index therapy for 12 months. Adjunctive therapy was needed in 22.5%, 18.5%, and 11.9% of bimatoprost, latanoprost, and benzalkonium chloride (BAK)-free travoprost patients, respectively. Median days to initiating adjunctive therapy were 64, 67, and 127 for bimatoprost, latanoprost, and BAK-free travoprost patients. Estimated first-year medical costs were $1,945, $1,803, and $1,730 for patients initiating therapy with bimatoprost, latanoprost, and BAK-free travoprost. Findings were consistent through sensitivity analysis.

Conclusions:

A BAK-free prostaglandin analog may permit longer duration of monotherapy and be associated with lower first-year treatment costs. Use of a claims database and the selection of new initiators of prostaglandin analogs limit the ability to project findings to all glaucoma patients.

Twelve-month, randomized, controlled trial of bimatoprost 0.01%, 0.0125%, and 0.03% in patients with glaucoma or ocular hypertension

PURPOSE

To evaluate the intraocular pressure (IOP)-lowering efficacy and safety of ophthalmic formulations of bimatoprost 0.01% and 0.0125% compared with bimatoprost 0.03%.

DESIGN

Prospective, randomized, double-masked, multicenter clinical trial.

METHODS

Patients with glaucoma or ocular hypertension were randomized to receive once-daily bimatoprost 0.01% (n = 186), bimatoprost 0.0125% (n = 188), or bimatoprost 0.03% (n = 187) for 12 months. The primary efficacy measure was IOP. Safety measures included adverse events and an objective assessment of conjunctival hyperemia.

RESULTS

Baseline mean IOPs were similar among treatment groups. Differences in mean IOP between the bimatoprost 0.01% or 0.0125% groups and the bimatoprost 0.03% group were less than 0.9 mm Hg throughout follow-up. Bimatoprost 0.01%, but not bimatoprost 0.0125%, was equivalent in efficacy to bimatoprost 0.03% based on predetermined criteria (limits of the 95% confidence interval of the between-group difference in mean IOP within +/- 1.5 mm Hg at all time points and within +/- 1 mm Hg at most time points). The overall incidence of treatment-related adverse events was reduced significantly in the bimatoprost 0.01% and bimatoprost 0.0125% groups compared with the bimatoprost 0.03% group (P < or = .034). The percentage of patients with a moderate to severe increase from the baseline macroscopic hyperemia score was: bimatoprost 0.01%, 3.2%; bimatoprost 0.0125%, 9.0%; bimatoprost 0.03%, 9.1% (P = .019 for bimatoprost 0.01% vs 0.03%).

CONCLUSIONS

Bimatoprost 0.01% was equivalent to bimatoprost 0.03% in lowering IOP throughout 12 months of treatment and demonstrated improved tolerability, including less frequent and severe conjunctival hyperemia. Bimatoprost 0.01% demonstrated a better benefit-to-risk ratio than bimatoprost 0.0125%.

Ocular preservatives: associated risks and newer options

Presence of a preservative in an ocular medication has often been considered a culprit in damaging the epithelium. However, the inclusion of a preservative is equally necessary, especially in multiple-dose containers, in order to protect against dangerous organisms accidentally gaining access during instillation. Benzalkonium chloride (BAK), chlorobutanol, chlorhexidine acetate (CHA), and phenylmercuric nitrate or acetate are some commonly used preservatives in eye preparations. New preservatives with a wide range of activity and good safety profiles have been introduced in the market, such as stabilized oxychloro complex (SOC), sofZia, and sodium perborate. In the present review, we discuss various conventional and newly proposed and patented preservative molecules for ocular use. Reasons for discontinuing traditional preservatives and the need for less-toxic molecules are discussed at length, along with newer options coming up in this area.

Impact of topical bimatoprost 0.01% and bimatoprost 0.03% on conjunctival irritation in rabbits

INTRODUCTION

The purpose of this study was to examine and compare the conjunctival irritation (congestion, swelling, and discharge) of topical bimatoprost ophthalmic solution 0.01% and bimatoprost ophthalmic solution 0.03% in rabbits.

METHODS

Six healthy New Zealand White rabbits were treated with either bimatoprost 0.01% or bimatoprost 0.03% (3 animals/group). One dose (2 drops/dose) of study medication was administered to the right eye of each animal every 30 minutes for 4.5 hours. Approximately 1 hour after the last dose, conjunctival irritation was assessed using a slit-lamp biomicroscope to individually evaluate conjunctival congestion, swelling, and discharge.

RESULTS

The mean conjunctival congestion, swelling and discharge scores for bimatoprost 0.03% were 1.67, 0.33 and 0.33, respectively, and for bimatoprost 0.01% were 2.00, 0.33 and 1.33, respectively.

CONCLUSIONS

Despite the lower drug concentration of the 0.01% formulation, bimatoprost 0.01% does not reduce conjunctival irritation, including conjunctival congestion, swelling, and discharge, in rabbits compared to bimatoprost 0.03%. Further studies would be needed to determine whether the increase in the mean conjunctival congestion and discharge scores may be attributed to the increased BAK concentration in the bimatoprost 0.01% formulation.

The effects of combination glaucoma medications on ocular surface epithelial cells

INTRODUCTION

The purpose of this study was to determine the effects of two commercially available combination topical ophthalmic medications on human ocular surface cells in vitro.

METHODS

Tissue culture plates (96-well) containing immortalized human corneal and conjunctival epithelial cells were divided into five groups. The test solutions examined were: timolol 0.5%+brimonidine 0.2%, containing 0.0050% benzalkonium chloride (BAK); timolol 0.5%+dorzolamide 2%, containing 0.0075% BAK; and preservative-free artificial tears. Balanced salt solution (BSS) was used as the live control, and a fixative solution containing 70% methanol and 0.2% saponin was used as the dead control. Cells were exposed to 100 microL of test or control solution for 25 minutes at 37 degrees C and 5% carbon dioxide (CO(2)). A live cell assay was used to measure the toxicity of combination treatments compared with BSS controls.

RESULTS

Exposure to timolol 0.5%+brimonidine 0.2% resulted in a significantly higher percentage of living conjunctival cells (48%+/-12%) as compared with timolol 0.5%+dorzolamide 2% (10%+/-5%, P<0.00001). In corneal cells, testing revealed 12%+/-3% live cells after timolol 0.5%+brimonidine 0.2% exposure compared with 2%+/-3% after timolol 0.5%+dorzolamide 2% (P<0.001).

CONCLUSIONS

Both combination medications demonstrated a significant reduction in the percentage of live corneal and conjunctival epithelial cells compared with control. However, cell cultures exposed to timolol 0.5%+dorzolamide 2% had significantly fewer live cells compared with cell cultures exposed to timolol 0.5%+brimonidine 0.2%. Further studies are needed to better understand the clinical significance of these findings in patients using these medications for chronic treatment of glaucoma and ocular hypertension.

Evaluation of the cytotoxic effects of ophthalmic solutions containing benzalkonium chloride on corneal epithelium using an organotypic 3-D model

Background

Benzalkonium chloride (BAC) is a common preservative used in ophthalmic solutions. The aim of this study was to compare the cytotoxic effects of BAC-containing ophthalmic solutions with a BAC-free ophthalmic solution using an organotypic 3-dimensional (3-D) corneal epithelial model and to determine the effects of latanoprost ophthalmic solution and its BAC-containing vehicle on corneal thickness in a monkey model.

Methods

The cytotoxicity of commercially available BAC-containing ophthalmic formulations of latanoprost (0.02% BAC) and olopatadine (0.01% BAC) was compared to that of BAC-free travoprost and saline in a corneal organotypic 3-D model using incubation times of 10 and 25 minutes. To compare the extent of differentiation of 3-D corneal cultures to monolayer transformed human corneal epithelial (HCE-T) cell cultures, expression levels (mRNA and protein) of the corneal markers epidermal growth factor receptor, transglutaminase 1 and involucrin were quantified. Finally, latanoprost ophthalmic solution or its vehicle was administered at suprapharmacologic doses (two 30 μL drops twice daily in 1 eye for 1 year) in monkey eyes, and corneal pachymetry was performed at baseline and at weeks 4, 13, 26 and 52.

Results

In the 3-D corneal epithelial culture assays, there were no significant differences in cytotoxicity between the BAC-containing latanoprost and olopatadine ophthalmic solutions and BAC-free travoprost ophthalmic solution at either the 10- or 25-minute time points. The 3-D cultures expressed higher levels of corneal epithelial markers than the HCE-T monolayers, indicating a greater degree of differentiation. There were no significant differences between the corneal thickness of monkey eyes treated with latanoprost ophthalmic solution or its vehicle (both containing 0.02% BAC) and untreated eyes.

Conclusion

The lack of cytotoxicity demonstrated in 3-D corneal cultures and in monkey studies suggests that the levels of BAC contained in ophthalmic solutions are not likely to cause significant direct toxicity to epithelium of otherwise normal corneas.

Effects of prostaglandin analog therapy on the ocular surface of glaucoma patients

Purpose:

To quantify changes in tear break-up time (TBUT), corneal staining and ocular surface disease index (OSDI) in glaucoma patients after switching therapy from latanoprost with 0.02% benzalkonium chloride (BAK) to travoprost with sofZia^™.

Methods:

Prospective consecutive case series evaluating patients before and 8 weeks after switching from latanoprost with BAK to travoprost with sofZia^™ in patients with baseline TBUT less than 6 seconds.

Results:

Forty eyes of 20 consecutive patients using latanoprost with BAK were switched to travoprost with sofZia^™. Mean TBUT prior to starting travoprost was 2.02 ± 0.71 seconds and increased to 6.34 ± 1.31 seconds 8 weeks after the switch (p < 0.001). Mean inferior corneal staining scores decreased from 2.40 ± 0.87 to 1.38 ± 0.59 (p < 0.001). Mean OSDI scores decreased from 26.31 ± 8.25 to 16.56 ± 6.19 (p < 0.001).

Discussion:

This report focuses on the status of the ocular surface, as documented by TBUT, corneal staining and OSDI, in patients switched from latanoprost with BAK to travoprost without BAK. The switch resulted in a statistically significant increase in TBUT and decreases in corneal staining and OSDI in patients with low baseline TBUT values.

Conclusion:

BAK, a common preservative for glaucoma drops, may increase OSD by disrupting the tear film and increasing conjunctival inflammation. In this study, a change from a BAK-preserved prostaglandin analog (PGA) to a non-BAK-preserved PGA resulted in a measurable improvement of TBUT, corneal staining and OSDI. Further studies are needed to better understand the impact of BAK-preserved medications on the ocular surface.

Quantitative analysis of conjunctival goblet cells after chronic application of topical drops

INTRODUCTION

Chronic topical glaucoma therapy has been reported to cause deleterious changes to the ocular surface epithelial layers. We compare changes in the number of goblet cells after chronic exposure to latanoprost preserved with 0.02% benzalkonium chloride (BAK) eye drops (Xalatan; Pfizer, NY, USA), travoprost preserved with sofZia eye drops (Travatan Z; Alcon, Fort Worth, TX, USA), or preservative-free artificial tears (Refresh Plus; Allergan, Irvine, CA, USA).

METHODS

Fifteen New Zealand white rabbits were randomised into groups of five (one eye was randomised for treatment) and received once-daily topical application of one of the three treatments for 30 days. Enucleation was performed at the end of the study followed by histologic analysis using mucin stains to identify goblet cells. Goblet cells were quantified and analysed using Student t tests to compare means between groups.

RESULTS

Goblet cells per high-power field were 2.21 (+/-0.40) in the latanoprost with BAK group, 6.02 (+/-1.20) in the travoprost with sofZia group, and 7.03 (+/-1.33) in the preservative-free artificial tear group. The number of goblet cells in the latanoprost with BAK group was significantly lower than the other two groups (P=0.0001). There was no statistically significant difference in goblet cell numbers between the travoprost with sofZia and preservative-free artificial tear group (P=0.24).

CONCLUSION

Our study illustrates that, in this animal model, once-daily dosing of latanoprost with 0.02% BAK resulted in goblet cell loss compared with dosing with either travoprost with sofZia or preservative-free artificial tears.

Repeated exposure to benzalkonium chloride in the Ex Vivo Eye Irritation Test (EVEIT): observation of isolated corneal damage and healing

The prediction of side-effects is a key issue in the REACH initiative on chemicals, in the production of cosmetics and in the preclinical testing of drugs. A new ex vivo test for repeated substance application is presented, that is able to identify corrosive and irritant effects on the eye by using crucial endpoints, such as cellular and morphological damage, and healing characteristics. The test is intended to replace the Draize eye test and to improve the preclinical testing of drugs and chemicals that are likely to come into direct contact with the cornea. The Ex Vivo Eye Irritation Test (EVEIT) is a self-healing system, involving living corneas obtained from abattoir rabbit eyes. The corneas are cultured in a similar way to the method used during the transplantation of corneal grafts. The corneas are exposed to multiple small, mechanical abrasions, and then test substances are repeatedly dropped onto the centres of the corneas. The test substances applied in this study were citrate-buffered hyaluronate eye drops and an artificial tear replacement, with increasing concentrations of up to 0.1% benzalkonium chloride. A dose-dependent inhibition of recovery and impairment of the lactate production mechanism in the cornea was observed with benzalkonium chloride treatment.

Comparison of corneal and conjunctival changes after dosing of travoprost preserved with sofZia, latanoprost with 0.02% benzalkonium chloride, and preservative-free artificial tears

PURPOSE

To evaluate corneal and conjunctival changes after chronic, once-daily dosing of travoprost preserved with sofZia, latanoprost preserved with 0.02% benzalkonium chloride (BAK), or preservative-free artificial tears.

METHODS

Thirty New Zealand white rabbits were randomized to receive once-daily instillation of travoprost with sofZia, latanoprost, or preservative-free artificial tears in 1 eye. Corneal epithelial changes were evaluated by transmission electron microscopy and graded on a standard scale by 2 masked observers. Conjunctival inflammation was evaluated by light microscopy after hematoxylin and eosin staining. Lymphocytes were counted in the epithelium and superficial stroma by 2 masked observers and compared among groups.

RESULTS

Corneal tissue treated with preservative-free artificial tears and travoprost with sofZia revealed similar changes under transmission electron microscopy (P = 0.53). Significantly more corneal epithelial damage was noted with latanoprost than travoprost with sofZia (P = 0.0001). The number of lymphocytes in the conjunctival epithelium and stroma was significantly lower in eyes treated with travoprost with sofZia than eyes treated with latanoprost (P = 0.0001). The number of conjunctival lymphocytes was similar among conjunctival specimens exposed to travoprost with sofZia and preservative-free artificial tears (P = 0.65).

CONCLUSIONS

Once-daily dosing of travoprost with sofZia produced significantly fewer corneal changes and less conjunctival inflammation than latanoprost preserved with BAK. Corneal and conjunctival changes noted with travoprost with sofZia were similar to those induced by preservative-free artificial tears. Glaucoma medication with high levels of BAK may cause more deleterious effects on the ocular surface than non-BAK-preserved medications. Human studies are needed to better understand the clinical effects of different preservative types and concentrations on the ocular surface.

The effect of drop vehicle on the efficacy and side effects of topical glaucoma therapy: a review

PURPOSE OF REVIEW

Topically applied medications are frequently used in ophthalmology to treat acute and chronic conditions, and are considered to be safer than their systemically applied counterparts, due to the reduced rate of systemic side effects.

RECENT FINDINGS

Many experimental and clinical studies have reported that the long-term use of topical medications in chronic ophthalmic conditions, such as glaucoma, may adversely affect the ocular surface. Preservatives play a pivotal role in almost all multidose ophthalmic preparations, inhibiting microbial growth and preserving the active drug. Consequently, preservatives are partially responsible for ocular side effects, although the exact mechanism of these side effects is not known.

SUMMARY

The role of preservatives in the efficacy and side effects of antiglaucoma drugs is reviewed. The recent advances in preservative technologies and their role in decreasing the side effects associated with antiglaucoma drugs are also discussed.