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

The use of benzalkonium chloride in topical glaucoma treatment: An investigation of the efficacy and safety of benzalkonium chloride-preserved intraocular pressure-lowering eye drops and their effect on conjunctival goblet cells

ENGLISH SUMMARY

Glaucoma is a leading cause of the global prevalence of irreversible blindness. The pathogenesis of glaucoma is not entirely known, but the major risk factors include advancing age, genetic predisposition, and increased intraocular pressure (IOP). The only evidence-based treatment is a lowering of IOP through the use of eye drops, laser procedures, or surgical interventions. Although laser treatment is gaining recognition as a first-choice treatment option, the most common approach for managing glaucoma is IOP-lowering eye drops. A major challenge in the treatment is the occurrence of adverse events and poor adherence. In this context, the ocular surface is an area of great concern, as most glaucoma patients have dry eye disease (DED), which is largely caused by eye drops. Preservation with benzalkonium chloride (BAK) is a controversial topic due to its potential role as a significant cause of DED. A systematic review and meta-analyses investigate potential differences in efficacy and safety between BAK-preserved and BAK-free anti-glaucomatous eye drops (I). Many of the included studies report on ocular surface damage caused by the application of BAK-preserved eye drops. However, the meta-analyses addressing hyperemia, number of ocular adverse events, and tear break-up time did not identify any significant differences. The latter is likely due to varying measurement methods, different endpoints, and study durations. It is, therefore, possible that the large variations between the studies conceal differences in the safety profiles. The efficacy meta-analysis finds that there are no differences in the IOP-lowering effect between BAK-preserved and BAK-free eye drops, indicating that BAK is not necessary for the effectiveness of eye drops. To promote more homogeneous choices of endpoints and methods when evaluating BAK-preserved and BAK-free glaucoma treatments, a Delphi consensus statement was performed. In this study, glaucoma experts and ocular surface disease experts reached consensus on the key factors to consider when designing such studies (II). The hope is to have more studies with comparable endpoints that can systematically show the potentially adverse effects of BAK. The preclinical studies in the current Ph.D. research focus on conjunctival goblet cells (GCs). GCs are important for the ocular surface because they release the mucin MUC5AC, which is an essential component of the inner layer of the tear film. BAK preservation may damage the GCs and result in a low GC density, leading to an unstable tear film and DED. The most commonly used IOP-lowering drugs are prostaglandin analogs (PGAs). Thus, the conducted studies investigate the effect of PGAs preserved in different ways on GCs. BAK-preserved latanoprost is cytotoxic to primary cultured human conjunctival GCs and results in a scattered expression of MUC5AC, in contrast to negative controls, where MUC5AC is localized around the cell nucleus (III). Preservative-free (PF) latanoprost is not cytotoxic and does not affect the MUC5AC expression pattern. Furthermore, BAK-preserved travoprost is found to be cytotoxic in a time-dependent manner, while Polyquad®-preserved travoprost does not affect GC survival at any measured time point (IV). Both Polyquad and BAK induce scattered expression of MUC5AC. The cytotoxicity of BAK-preserved PGA eye drops is higher compared to the safer profile of PF and Polyquad-preserved PGA eye drops (V). Additionally, PF latanoprost does not increase the release of the inflammatory markers interleukin (IL)-6 and IL-8, unlike BAK-preserved latanoprost. A review highlights the active and inactive components of IOP-lowering eye drops (VI). Several preclinical and clinical studies have identified adverse effects of BAK. Although other components, such as the active drug and phosphates, can also cause adverse events, the review clearly states that BAK alone is a major source of decreased tolerability. The conclusion of this thesis is that BAK preservation is unnecessary and harmful to the ocular surface. The preclinical studies demonstrate that GCs die when exposed to BAK. Furthermore, they find that BAK induces a pro-inflammatory response. The review included in the thesis concludes that BAK should be phased out of eye drops for chronic use. Overall, the inclusion of BAK poses a risk of developing DED and poor adherence, which can ultimately lead to disease progression and blindness.

The molecular aspect of anti-glaucomatous eye drops - are we harming our patients?

Glaucoma is one of the leading causes of irreversible blindness. Progression is halted with a reduction in intraocular pressure (IOP), which is most often achieved with eye drops. A major challenge in the topical treatment of glaucoma patients is the many side effects and the resulting reduced adherence. Side effects may of course be due to the molecular properties of the active pharmaceutical ingredients (APIs). There are currently six different APIs available: prostaglandin analogues, β-adrenergic inhibitors, α-adrenergic agonists, carbonic anhydrase inhibitors, rho-kinase inhibitors and muscarinic 3 agonists. But the additives used in eye drops are also known to cause damage to the ocular surface and to some extent also to the deeper tissues. Said additives are considered inactive molecular components and are added to secure for instance viscosity and pH value, and to prevent contamination. There has been an increasing focus on the harmful effects of preservatives, with the most commonly used preservative benzalkonium chloride (BAK) being particularly controversial. BAK has long been recognized as a toxin that increases the risk of ocular discomfort. This can affect the adherence and ultimately result in lack of disease control. Other issues include the addition of certain buffers, such as phosphates, and varying pH values. This review will address the different molecular components of the IOP-lowering eye drops and what to be aware of when prescribing topical glaucoma treatment.

A Critical Appraisal of the Physicochemical Properties and Biological Effects of Artificial Tear Ingredients and Formulations

Dry eye disease is among the most prevalent diseases affecting the ocular surface. Artificial tears remain the cornerstone therapy for its management. There are currently a wide variety of marketed artificial tears available to choose from. These artificial tears differ significantly in their composition and formulation. This article reviews the physicochemical and biological properties of artificial tear components and how these characteristics determine their use and efficacy in the management of dry eye. Furthermore, this article also discusses the various formulations of artificial tears such as macro and nanoemulsion and the type of preservatives present in them.

Propylene Glycol and Hydroxypropyl Guar Nanoemulsion - Safe and Effective Lubricant Eye Drops in the Management of Dry Eye Disease

Dry eye disease (DED) is a chronic condition of the ocular surface characterized by a loss of the tear film homeostasis and accompanied by symptoms such as eye discomfort and visual disturbances. DED is classified as aqueous deficient dry eye (ADDE), evaporative dry eye (EDE), and mixed dry eye etiologies. The mainstay treatment in the management of DED is artificial tear drops or lubricant eye drops that replenish the aqueous and/or lipid layer of the tear film. These are available as both lipid-based and non-lipid-based formulations, with/without preservatives. Lipid-based lubricant eye drops can stabilize the tear film lipid layer, reduce tear evaporation, and improve signs of EDE. In this review, we present the formulation components, mechanism of action, and summary of preclinical and clinical evidence on a lipid-based formulation - propylene glycol-hydroxypropyl guar (PG-HPG) nanoemulsion lubricant eye drops (Systane^TM Complete). These eye drops consist of the demulcent (lubricant), PG (0.6%). HPG forms a soft, thin, cross-linked in situ gel matrix with borate ions, when exposed to the tear film, which prolongs lubricant retention and provides ocular surface protection. Dimyristoyl phosphatidyl glycerol, an anionic phospholipid, helps in replenishing the lipid layer of the tear film. Moreover, the nanoemulsion formulation serves as a depot for delivery of dimyristoyl phosphatidyl glycerol to enhance ocular surface coverage. Preclinical and clinical evidence demonstrate that PG-HPG nanoemulsion lubricant eye drops are safe and effective in providing temporary relief of symptoms of DED, regardless of its subtypes. Specifically, it provides sustained reduction in dry eye symptoms, improves tear film stability/lipid layer grade, and improves ocular surface characteristics.

Categorization of Marketed Artificial Tear Formulations Based on Their Ingredients: A Rational Approach for Their Use

Dry eye disease is a common ocular condition affecting millions of people worldwide. Artificial tears are the first line therapy for the management of dry eye disease. Artificial tear formulations contain a variety of active ingredients, biologically active excipients, and preservatives. Many of these formulations are also available as preservative-free. This study was conducted to inspect artificial tear formulations currently marketed in the United States for their active ingredients, biologically relevant excipients, and preservatives. The marketed artificial tears were examined at various US retail pharmacy chains and using the manufacturers’ website to compile information about active ingredients, inactive ingredients, and preservatives. The currently marketed artificial tears can be grouped into four categories based on their active ingredients. The artificial tears also contain biologically active chemicals listed as inactive ingredients, which have osmoprotectant, humectant, and tear film lipid layer or mucous layer mimicking properties. Most artificial tears contain vanishing type preservatives such as purite or sodium perborate and safer quaternary compound polyquaternium-1. The majority of these artificial tear formulations are also available as preservative-free single dose unit. The study provides a formulary of artificial tears based on active ingredients, biologically active excipients, and the preservative-free option. The formulary should assist healthcare providers in making a stepwise and rational selection of appropriate artificial tears for patients suffering from dry eye disease.

Physicochemical characterization of a DMPC-based nanoemulsion for dry eye and compatibility test with soft contact lenses in vitro

INTRODUCTION

The use of contact lenses (CL) is often associated with hallmark symptoms of dry eye disease (DED) such as red eye and dryness. Even though lipid-based artificial tears are already marketed for DED, there is little evidence that supports their use while wearing soft CL.

METHODS

An oil in water (O/W) nanoemulsion was formulated with a highly-stable oily phase composed of castor oil and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). Physicochemical characterization of the DMPC-based nanoemulsion (DMPC-NE) was performed using the Zetasizer Nano ZSP, and its long-term stability was evaluated over 24 months; in addition, the in vitro cytotoxicity of DMPC-NE was determined by Neutral Red Uptake (NRU) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Finally, the physical compatibility of the DMPC-NE with soft CL was tested by measuring the power, diameter, thickness and UV transmittance of two different types of CL.

RESULTS

DMPC-NE had a mean particle size of 86.48 ± 4.22 nm, a polydispersity index of 0.22 ± 0.01 and a zeta potential of -33.23 ± 0.93 mV that remained with no changes after 24 months. DMPC-NE formulation, free of preservatives, showed no cytotoxicity and it was compatible with the physical properties of FDA-class II and -class IV CL.

CONCLUSION

DMPC-NE is a highly stable formulation for dry eye that is safe to be used while wearing soft CL.

Ocular toxicology: synergism of UV radiation and benzalkonium chloride

PURPOSE

To investigate the combined toxic effect of ultraviolet (UV) radiation and benzalkonium chloride (BAK), a common preservative in ophthalmic eye drops, on human corneal epithelial cells (HCEC).

METHODS

Cultured HCEC were exposed to different combined and separate UV (280-400 nm) and BAK solutions at relevant human exposure levels. Human exposure to UV can occur before, during, or after eye drop installation, therefore, three different orders of ocular exposures were investigated: UV and BAK at the same time, UV first followed by BAK, and BAK first followed by UV. Control treatments included testing HCEC exposed to BAK alone and also HCEC exposed to UV alone. In addition, phosphate-buffered saline (PBS) was used as a negative control. After exposure, cell metabolic activity of the cultures was measured with PrestoBlue, and cell viability was determined using confocal microscopy with viability dyes.

RESULTS

BAK alone reduced the metabolic activity and cell viability of HCEC in a dose- and time-dependent manner. UV alone at a low dose (0.17 J/cm²) had little toxicity on HCEC and was not significantly different from PBS control. However, UV plus BAK showed combined effects that were either greater than (synergistic) or equal to (additive) the sum of their individual effects. The synergistic effects occurred between low dose UV radiation (0.17 J/cm²) and low concentrations of BAK (0.001%, 0.002%, 0.003%, and 0.004%).

CONCLUSIONS

This investigation determined that at relevant human exposure levels, the combination of UV radiation (280-400 nm) and BAK can cause synergistic and additive toxic effects on human corneal epithelial cells. This finding highlights the importance of considering the combined ocular toxicity of BAK and solar radiation in the risk assessment of BAK-preserved ophthalmic solutions.

Meibomian Gland Features and Conjunctival Goblet Cell Density in Glaucomatous Patients Controlled With Prostaglandin/Timolol Fixed Combinations: A Case Control, Cross-sectional Study

PURPOSE

To investigate, using in vivo confocal microscopy (IVCM), the Meibomian gland (MG) features and conjunctival goblet cell density (GCD) in glaucomatous patients controlled with prostaglandin/timolol fixed combinations (PTFCs).

MATERIALS AND METHODS

In this cross-sectional study, 60 white patients were treated with PTFCs, 15 with latanoprost+timolol (L+T) unfixed combination, and 15 controls were enrolled. Patients underwent the Ocular Surface Disease Index questionnaire, tear film breakup time, corneal staining, Schirmer test I, and IVCM of MGs and goblet cells. The main outcome measures were: mean Meibomian acinar density (MMAD) and area (MMAA), inhomogeneity of glandular interstice (InI) and acinar wall (InAW), and GCD.

RESULTS

PTFCs were: latanoprost/timolol (LTFC, 15 eyes), travoprost/timolol (TTFC, 15), bimatoprost/timolol (BTFC, 15), and preservative-free bimatoprost/timolol (PF-BTFC, 15) fixed combinations. Mean time on therapy did not differ among treatments. IVCM documented lower GCD, MMAD, and MMAA (P<0.001), and greater InI and InAW (P<0.05) in glaucoma patients compared with controls. L+T showed worse values compared with PTFCs and PF-BTFC (P<0.05). Preserved PTFCs showed lower MMAD, MMAA, GCD, and greater InI and InAW compared with PF-BTFC (P<0.05) and controls (P<0.001). Differences were not found among PTFCs. InI and InAW significantly correlated with Ocular Surface Disease Index and breakup time (P<0.001), corneal staining (P<0.05), and GCD (P<0.001); GCD correlated with MMAD (P<0.05).

CONCLUSIONS

PTFCs were less toxic towards MGs and goblet cells compared with the L+T unfixed combination, with PF-BTFC presenting the most tolerated profile. These findings should be carefully considered given the role of these structures in the induction of the glaucoma-related ocular surface disease.

The use of preservatives in dry eye drops

Topical ocular preparations are widely recommended by health care professionals, or chosen by patients, to help manage dry eye disease (DED). The chronic and progressive nature of DED may result in the administration of topical products several times a day, over a period of many years. Given DED is a condition that by definition affects the ocular surface, it is important to understand how the repeated use of eye drops may impact the ocular surface, influence clinical signs, affect symptoms, and impact the overall disease process of dry eye. The component in topical preparations with the greatest potential to adversely affect the ocular surface is the preservative. This paper reviews the literature in relation to the use of preservatives in formulations for dry eye. The ocular effects of benzalkonium chloride (BAK) are summarised and compared to the performance of alternative preservatives and preservative-free formulations. Use of preserved and preservative-free drops in relation to the management of varying stages of DED is discussed.

Effects of Anti-Glaucoma Prostaglandin Ophthalmic Solutions on Cultured Human Corneal Epithelial Cells

Purpose: We compare the cytotoxicity of anti-glaucoma prostaglandin ophthalmic solutions on human corneal epithelial cells and elucidate mechanisms of toxicity. Methods: Cell viability was examined using MTS assay, and morphological changes of the cells were observed. Induction of necrosis/apoptosis was measured by colorimetric caspase assay. The production of Reactive oxygen species (ROS) and release of cytokines were analyzed using 2', 7'-dichlorodihydrofluorescein diacetate and bead-based indirect immunofluorescent assay, respectively. Results: Xalatan, Lumigan 0.01%, and Lumigan 0.03% decreased cell viability and induced morphological changes. Xalatan and Lumigan 0.01% induced necrosis. Xalatan, Lumigan 0.01%, Lumigan 0.03%, and Taflotan stimulated ROS production. Travatan and Lumigan 0.03% increased concentrations of Interleukin (IL)-6 and IL-8 in culture media. Conclusions: Xalatan and Lumigan 0.01% ophthalmic solutions demonstrated potent cytotoxicity compared with Lumigan 0.03%, Travatan, Taflotan, and Taflotan UD. Taflotan UD, compared to Taflotan 0.0015%, induced less oxidative stress and apoptotic signalling. The cytotoxicity might be partly associated with benzalkonium chloride.

Preservatives in glaucoma medication

Preservatives continue to be in widespread use in ophthalmic medications due to the convenience they provide, regulatory requirements and the higher cost of alternatives. Benzalkonium chloride (BAK) remains the most commonly used preservative but there is a trend towards the use of preservative-free (PF) drops for glaucoma, although at a higher price. An extensive body of literature explores BAK toxicity on ocular structures in animal and laboratory studies (in vitro and in vivo). Non-randomised controlled studies have provided some supporting evidence of its toxicity in patients, especially in those with pre-existing ocular surface disease (OSD) or on multiple medications. However, there have been very few randomised controlled trials that compare the same medication with and without BAK preservative. Several of these trials have never been published in any peer reviewed journals. Notwithstanding, those that have been published, have not demonstrated any clear benefits of the BAK-free formulations. Short duration and exclusion of those with OSD are limitations of these studies. There is a lack of evidence of clinically significant harm from a small number of BAK preserved drops in patients without OSD. This means that generally more expensive PF glaucoma medications should only be recommended for those on poly pharmacy or those with OSD but are not necessarily required for all patients.

The Effects of Phacoemulsification on Intraocular Pressure and Topical Medication Use in Patients With Glaucoma: A Systematic Review and Meta-analysis of 3-Year Data

PURPOSE

For patients with comorbid cataract and primary open-angle glaucoma (POAG), guidance is lacking as to whether cataract extraction and traditional filtering surgery should be performed as a staged or combined procedure. Achieving this guidance requires an evidence-based understanding of the effects of phacoemulsification alone on intraocular pressure (IOP) in patients with POAG. For this reason, a systematic review and meta-analysis was undertaken to synthesize evidence quantifying the effect of phacoemulsification on IOP and the required number of topical glaucoma medications in patients with cataract and POAG.

MATERIALS AND METHODS

Database searches were last run on August 15, 2016 to identify potentially relevant studies. Identified articles were screened for relevance and meta-analysis was used to compute postoperative mean and percentage reduction in IOP (IOPR%) as well as mean difference in topical glaucoma medications.

RESULTS

The search strategy identified 1613 records. Thirty-two studies (1826 subjects) were included in quantitative synthesis. A 12%, 14%, 15%, and 9% reduction in IOP from baseline occurred 6, 12, 24, and 36 months after phacoemulsification. A mean reduction of 0.57, 0.47, 0.38, and 0.16 medications per patient of glaucoma medication occurred 6, 12, 24, and 36 months after phacoemulsification.

CONCLUSIONS

Phacoemulsification as a solo procedure does lower IOP in patients with POAG, and reduces dependency on topical glaucoma medications. These effects appear to last at least 36 months with gradual loss of the initial effect noted after 2 years. Certain populations appear to experience much greater reductions in IOP than others and future work to identify these high responding patients is needed.

Efficacy and tolerability of benzalkonium chloride-free travoprost in glaucoma patients switched from benzalkonium chloride-preserved latanoprost or bimatoprost

Introduction

The preservative benzalkonium chloride (BAK) is used to preserve several topical, intraocular pressure (IOP)-lowering glaucoma medications but can cause tolerability concerns that may lead to decreased adherence to treatment and ultimately diminish the effectiveness of IOP control. The study aimed to determine the efficacy and tolerability of BAK-free travoprost preserved with polyquaternium-1 in glaucoma patients switched from BAK-preserved latanoprost or bimatoprost.

Methods

This 12-week, open-label study was conducted in Europe between December 2011 and February 2013. We enrolled adult patients with open-angle glaucoma or ocular hypertension who were receiving BAK-preserved latanoprost 0.005% or bimatoprost 0.01% and, in the opinion of the investigator, would benefit from transition to BAK-free travoprost 0.004% preserved with polyquaternium-1 because of tolerability concerns. Assessments included IOP, proportion of patients with IOP ≤18 mmHg, ocular surface status, hyperemia, patient treatment preference, and adherence. Adverse events were recorded throughout the study.

Results

Of the 202 patients screened, 187 patients were included in the intent-to-treat population (mean age, 66.6 years; range, 19–90 years). The mean IOP significantly reduced from baseline (17.0 mmHg) to week 6 (mean change, −1.17 mmHg; P<0.001) and week 12 (−1.16 mmHg; P<0.001). At week 12, more patients achieved IOP ≤18 mmHg (81.2% versus 73.3% at baseline), and ocular surface disease severity improved from baseline to week 12. Most patients preferred BAK-free travoprost (74.9%) versus their previous medication and were very confident in their adherence (84.1%). Reduced visual acuity and eye pruritus were the most common adverse events (2.5% each).

Conclusion

BAK-free travoprost 0.004% preserved with polyquaternium-1 was efficacious and well tolerated and may be an advantageous prostaglandin analog option for patients with open-angle glaucoma or ocular hypertension who are intolerant to BAK-preserved latanoprost or bimatoprost.

Comparison of the Efficacy of Fluorometholone With and Without Benzalkonium Chloride in Ocular Surface Disease

PURPOSE

The purpose of this study was to compare the cytotoxicity and antiinflammatory effect of preserved and unpreserved 0.1% fluorometholone (FML).

METHODS

Drug-induced morphological changes and cytotoxicity were examined in human corneal epithelial cells. Dry eye was induced in mice by treatment with 0.2% benzalkonium chloride (BAC) for the first 2 weeks, and then, the eyes (4 groups; Normal saline, BAC, preserved FML, and unpreserved FML) were treated thrice daily with each formulation for the next 2 weeks. Corneal tissues were embedded in paraffin and stained with hematoxylin and eosin for histopathological examination. Immunofluorescence staining was performed for tumor necrosis factor-α, interleukin-6, and human leukocyte antigen-DR. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay was performed to evaluate drug-induced cytotoxicity.

RESULTS

BAC and preserved FML caused cell shrinkage and detachment from the plate in a dose-dependent manner, and cell viability decreased significantly. However, cytotoxicity was reduced on treatment with unpreserved FML. Hematoxylin-eosin staining revealed surface desquamation, irregular surface, loss of cell borders, and stromal shrinkage in the group treated with BAC. On BAC exposure, tumor necrosis factor-α, interleukin-6, and human leukocyte antigen-DR were strongly detected, and cytotoxicity was markedly increased, as evidenced by a positive result in the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Ocular surface damage and inflammation were slightly reduced on treatment with preserved FML. In comparison, unpreserved FML did not induce morphological changes; moreover, decreased cell cytotoxicity and ocular surface inflammation were observed.

CONCLUSIONS

The cytotoxicity of antiinflammatory eye drops evaluated in this study was induced by the preservative BAC. Accordingly, unpreserved FML is more effective than preserved eye drops in decreasing ocular inflammation.

Acute cytotoxic effects of marketed ophthalmic formulations on human corneal epithelial cells

The purpose of the study was to devise a fast, reliable and sensitive cell viability assay for assessment of acute cytotoxicity on human corneal epithelial cells by using a clinically relevant exposure time. Acute cytotoxic effects of the pharmaceutical excipients benzalkonium chloride (BAC), macrogolglycerol hydroxystearate (MGHS40), polysorbate 80 (PS80) and marketed ophthalmic formulations (Lumigan(®), Monoprost(®), Taflotan(®), Travatan(®), Xalatan(®)) containing these excipients were tested. Human corneal epithelial cell (HCE-T) viability was assessed by measuring the reduction of resazurin to highly fluorescent resorufin. Expression of the tight junction proteins in HCE-T cells were characterized by immunofluorescence staining. Presence of tight junction proteins in HCE-T cells was demonstrated. BAC preserved ophthalmic formulations showed concentration-dependent and time-dependent cytotoxicity to human corneal epithelium. In contrast, no acute cytotoxicity of non-ionic stabilizing/solubilizing excipients (MGSH40 and PS80) or ophthalmic formulation containing these excipients was observed. Marketed ophthalmic formulations used for glaucoma medication show differential toxicity on human corneal epithelial cells. The present study revealed that BAC-preserved ophthalmic formulations were able to induce acute cytotoxic effects even during a clinically relevant exposure time, which was not observed with MGSH40 and PS80 excipients or ophthalmic formulations containing these excipients.

Acute Corneal Toxicity of Combined Antiglaucoma Topical Eyedrops

PURPOSE

To investigate the corneal toxicity of three combined antiglaucoma topical eyedrops using transepithelial electrical resistance (TER) and scanning electron microscopy (SEM).

METHODS

Corneal TER changes after a 60-s exposure to latanoprost/timolol with 0.02% benzalkonium chloride (BAC), travoprost/timolol with polyquaternium-1, and dorzolamide/timolol with 0.005% BAC were measured in living rabbits. Corneal damage was also examined by SEM. Hank's balanced salt solution (HBSS) was used as a control.

RESULTS

There was a significant decrease in the corneal TER after exposure of the cornea to latanoprost/timolol with 0.02% BAC. Travoprost/timolol with polyquaternium-1 and dorzolamide/timolol with 0.005% BAC did not produce any significant decrease in the corneal TER as compared to HBSS control eyes. SEM revealed that superficial cells of corneas treated with latanoprost/timolol with 0.02% BAC were damaged and exhibited degenerated microvilli. Conversely, the superficial cells of corneas exposed to travoprost/timolol with polyquaternium-1 or dorzolamide/timolol with 0.005% BAC appeared normal and had normal microvilli under SEM examinations.

CONCLUSION

The corneal toxicity of latanoprost/timolol with 0.02% BAC is greater than that of travoprost/timolol with polyquaternium-1 and dorzolamide/timolol with 0.005% BAC. Latanoprost/timolol contains 0.02% BAC, which may be responsible for the corneal toxicity.

Congenital Corneal Anesthesia and Neurotrophic Keratitis: Diagnosis and Management

Neurotrophic keratitis (NK) is a rare degenerative disease of the cornea caused by an impairment of corneal sensory innervation, characterized by decreased or absent corneal sensitivity resulting in epithelial keratopathy, ulceration, and perforation. The aetiopathogenesis of corneal sensory innervation impairment in children recognizes the same range of causes as adults, although they are much less frequent in the pediatric population. Some extremely rare congenital diseases could be considered in the aetiopathogenesis of NK in children. Congenital corneal anesthesia is an extremely rare condition that carries considerable diagnostic and therapeutic problems. Typically the onset is up to 3 years of age and the cornea may be affected in isolation or the sensory deficit may exist as a component of a congenital syndrome, or it may be associated with systemic somatic anomalies. Accurate diagnosis and recognition of risk factors is important for lessening long-term sequelae of this condition. Treatment should include frequent topical lubrication and bandage corneal or scleral contact lenses. Surgery may be needed in refractory cases. The purpose of this review is to summarize and update data available on congenital causes and treatment of corneal hypo/anesthesia and, in turn, on congenital NK.

Fixed Combination of Travoprost and Timolol Maleate Reduces Intraocular Pressure in Japanese Patients with Primary Open-Angle Glaucoma or Ocular Hypertension: A Prospective Multicenter Open-Label Study

Introduction

The efficacy of lowering intraocular pressure (IOP) and safety of switching to travoprost/timolol fixed combination ophthalmic solution (Duotrav^®, Alcon Laboratories, Inc., Fort Worth, TX, USA) in patients with primary open-angle glaucoma, normal tension glaucoma or ocular hypertension undergoing prostaglandin analog (PGA) monotherapy was investigated.

Methods

Patients treated with travoprost, latanoprost, tafluprost, or bimatoprost for ≥3 months and requiring additional medication were switched to Duotrav without washout. Baseline IOP was calculated from measurements at two visits during PGA monotherapy. IOP reductions at 4, 8, and 12 weeks after switching to Duotrav and adverse events were assessed.

Results

Of 162 patients enrolled, 157 patients (96.9%) with ≥4 weeks of follow-up after switching to Duotrav were analyzed. The mean IOP decreased significantly (baseline = 16.3 ± 3.1 mmHg; 4 weeks = 14.6 ± 3.1 mmHg, 8 weeks = 14.7 ± 3.3 mmHg, 12 weeks = 14.6 ± 3.2 mmHg; all P < 0.0001). When study eyes were divided into three groups according to baseline IOP (≥19 mmHg: 33 eyes, 21.0%; ≥15 to <19 mmHg: 78 eyes, 49.7%; <15 mmHg: 46 eyes, 29.3%), all groups showed significant IOP reductions (P = 0.0324 ~ P < 0.0001) after switching to Duotrav. Twenty-seven of 166 patients (16.3%) in the safety analysis experienced adverse events and 26/166 patients (15.7%) experienced adverse events, for which a relationship to Duotrav could not be ruled out. Adverse events in five patients led to treatment discontinuation (eye pruritus; eye irritation; increased blood pressure and rash; increased blurred vision; deepening of the eyelid sulcus and blepharoptosis). Twelve weeks after treatment switching, eyelash changes, blepharal pigmentation and deepening of the eyelid sulcus occurred in 42 (26.8%), 29 (18.5%), and 13 (8.3%) cases, respectively, among 157 patients with follow-up. There was no significant worsening from baseline for superficial punctate keratopathy (SPK) or conjunctival hyperemia after switching (SPK score: baseline = 0.58 ± 1.31; 12 weeks = 0.92 ± 1.76, P = 0.1819; conjunctival hyperemia score: baseline = 0.41 ± 0.64; 12 weeks = 0.49 ± 0.63, P = 0.3774).

Conclusion

Our findings confirm that switching to Duotrav^® in PGA monotherapy patients shows IOP-lowering effect with minimal safety concerns.

Funding

Japan Association of Health Service and Alcon Japan. Ltd.

Trial registration

UMIN Clinical Trials Registry identifier, UMIN000007028.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-015-0246-9) contains supplementary material, which is available to authorized users.

iStent with Phacoemulsification versus Phacoemulsification Alone for Patients with Glaucoma and Cataract: A Meta-Analysis

Background

Minimally invasive glaucoma surgeries (MIGS) have attracted significant attention, as they have been reported to lower intra-ocular pressure (IOP) and have an excellent safety profile. The iStent is an example of a minimally invasive glaucoma device that has received particular attention due to its early and wide spread utilization. There is a growing body of evidence supporting its use at the time of phacoemulsification to help lower IOP. However, it is still not clear how much of the IOP lowering effect can be attributed to the iStent, the crystalline lens extraction or both when inserted concurrently at the time of phacoemulsification. This has been an important issue in understanding its potential role in the glaucoma management paradigm.

Purpose

To conduct a systematic review and meta-analysis comparing the IOP lowering effect of iStent insertion at the time of phacoemulsification versus phacoemulsification alone for patients with glaucoma and cataracts.

Methods

A systematic review was conducted utilizing various databases. Studies examining the IOP lowering effect of iStent insertion in combination with phacoemulsification, as well as studies examining the IOP lowering effect of phacoemulsification alone were included. Thirty-seven studies, reporting on 2495 patients, met the inclusion criteria. The percentage reduction in IOP (IOPR%) and mean reduction in topical glaucoma medications after surgery were determined. The standardized mean difference (SMD) was computed as a measure of the treatment effect for continuous outcomes taking into account heterogeneity. Fixed-effect and random-effect models were applied.

Results

A 4% IOP reduction (IOPR%) from baseline occurred following phacoemulsification as a solo procedure compared to 9% following an iStent implant with phacoemulsification, and 27% following 2 iStents implants with phacoemulsification. Compared with cataract extraction alone, iStent with phacoemulsification resulted in significant reduction in the post-operative IOP (IOPR%) (SMD = -0.46, 95% CI: [-0.87, -0.06]). A weighted mean reduction in the number of glaucoma medications per patient was 1.01 following phacoemulsification alone compared to 1.33 after one iStent implant with phacoemulsification, and 1.1 after 2 iStent implants with phacoemulsification. Compared to cataract extraction alone, iStent with cataract extraction showed a significant decrease in the number of glaucoma medications (SMD = -0.65, 95% CI: [-1.18, -0.12]). Funnel plots suggested the absence of publication bias.

Conclusion

Both iStent implantation with concurrent phacoemulsification and phacoemulsification alone result in a significant decrease in IOP and topical glaucoma medications. In terms of both reductions, iStent with phacoemulsification significantly outperforms phacoemulsification alone.

iStent as a Solo Procedure for Glaucoma Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Glaucoma is a leading cause of irreversible blindness. It is firmly entrenched in the traditional treatment paradigm to start with pharmacotherapy. However, pharmacotherapy is not benign and has been well documented to have a number of significant challenges. Minimally invasive glaucoma surgery (MIGS) that targets the outflow pathway with minimal to no scleral dissection has resulted in the need to reconsider the glaucoma treatment paradigm.

PURPOSE

To perform a systematic review and meta-analysis to evaluate and quantify the effect on post-operative intraocular pressure (IOP) and number of topical glaucoma medications, in patients receiving the iStent MIGS device as the solo procedure without concurrent cataract surgery.

METHODS

A systematic review was conducted by searching various databases between January 1, 2000, and June 30, 2014. Studies reporting up to a maximum follow-up period of 24 months were retrieved and screened using the EPPI-Reviewer 4 gateway. Percentage reduction in IOP (IOPR%), and mean reduction in topical glaucoma medications after surgery were computed. Meta-analysis was performed using STATA v. 13.0. The standardized mean difference (SMD) was calculated as the effect size for continuous scale outcomes. Heterogeneity was determined using the I2 statistics, Z-value, and χ2 statistics. Fixed-effect and random-effect models were developed based on heterogeneity. Sub-group analysis was performed based on the number of iStents implanted and the follow-up period. The outcome measures were changes in the IOP and number of glaucoma medications.

RESULTS

The search strategy identified 105 records from published literature and 9 records from the grey literature. Five studies with 248 subjects were included for quantitative synthesis. A 22% IOP reduction (IOPR%) from baseline occurred at 18-months after one iStent implant, 30% at 6-months after two iStents implantations, and 40% at 6-months after implantation of three iStents. A mean reduction of 1.2 bottles per patient of topical glaucoma medications occurred at 18-months after one iStent implant, 1.45 bottles per patient at 6-months after two iStents, and one bottle of medication per patient was reduced at 6-months following placement of three iStents implants. Meta-analysis results showed a significant reduction in the IOP after one iStent (SMD = -1.68, 95% CI: [-2.7, -0.61]), two iStents (SMD = -1.88, 95% CI: [-2.2, -1.56]), and three iStents (SMD = -2, 95% CI: [-2.62, -1.38]) implantation. Results showed a significant drop in the topical glaucoma medications after one iStent (SMD = -2.11, CI: [-3.95, -0.27]), two iStent (SMD = -1.88, CI: [-2.20, -1.56]), and three iStents (SMD = -2.00, CI: [-2.62, -1.38]) implantation. The maximum reduction in IOP occurred at 12-months (SMD = -2.21, CI: [-2.53, -1.88]) and a significant reduction in post-operative topical glaucoma medications occurred even after 18-months of iStent implantation (SMD = -0.71, CI: [-1.15, -0.26]).

CONCLUSION

iStent implantation as a solo procedure without concurrent cataract extraction does lower IOP, and reduces the dependency on glaucoma medications. This effect seems to last at least 18 months.

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.

Projected cost comparison of Trabectome, iStent, and endoscopic cyclophotocoagulation versus glaucoma medication in the Ontario Health Insurance Plan

PURPOSE

To compare the direct cost of treating glaucoma patients with Trabectome, iStent, and endoscopic cyclophotocoagulation (ECP) versus topical medications in Ontario, Canada. Costs are projected over a 6-year period, and presented on a per-patient level from the perspective of the Ontario Health Insurance Plan (OHIP).

METHODS

The per-bottle cost of each medication was obtained from the 2011 Ontario Drug Benefit (ODB) formulary. A wastage adjustment fee was added to the cost, as was a pharmacy markup, and an ODB dispensing fee. Previously published medication prescription rates were used to determine the frequency with which each medication is prescribed. We estimated the overall cost by taking a weighted average of the cost of each class of glaucoma medications.The cost of each glaucoma device was determined by contacting local distributors. We then added the cost of disposables used during surgery (viscoelastic and keratome) to the cost of each procedure. Start-up costs for each device and surgeons' fees were excluded from the overall cost.

RESULTS

At 6 years, treatment with the Trabectome offered a cumulative cost savings of $279.23, $1572.55, and $2424.71 per patient versus monodrug, bidrug, and tridrug therapy, respectively. A cumulative cost difference of -$20.77, $1272.55, and $2124.71 per patient were found when comparing iStent versus monodrug, bidrug, and tridrug therapy, respectively. Treatment with ECP yielded a cost savings of $779.23, $2072.55, and $2924.71 per patient versus monodrug, bidrug, and tridrug therapy, respectively.

CONCLUSIONS

Over a projected period of 6 years, the Trabectome, iStent, and ECP may all offer a modest cost savings to OHIP versus the cost of glaucoma medication. Further analysis of direct and indirect costs to patients as well as quality of life assessments will help further delineate the role of these treatments in the glaucoma treatment paradigm.

Trehalose-based eye drops preserve viability and functionality of cultured human corneal epithelial cells during desiccation

This paper presents the evaluation of cytoprotective ability of trehalose-based eye drops in comparison with commercially available preparations during the experimental desiccation of cultured human corneal epithelial cells. Cultured human corneal epithelial cells (hCEC) underwent incubation with 7 different, commercially available medicaments used commonly in dry eye syndrome treatment, followed by desiccation trial performed on air under the flow hood for 5, 15, 30, and 45 minutes. Cell viability was quantified by live/dead fluorescent assay, while the presence of apoptotic cells was estimated by immunofluorescent staining for active caspase 3 protein. The preservation of membrane functions was evaluated using neutral red staining, while the preservation of proper morphology and phenotype was determined by fluorescent staining for actin filaments, nuclei, and p63 protein. The trehalose-based eye drops showed the highest efficiency in prevention of cell death from desiccation; moreover, this preparation preserved the normal cellular morphology, functions of cell membrane, and proliferative activity more effectively than other tested medicaments.

24-hour efficacy of travoprost/timolol BAK-free versus latanoprost/timolol fixed combinations in patients insufficiently controlled with latanoprost

INTRODUCTION

To compare the 24-h intraocular pressure (IOP) control and tolerability of travoprost/timolol benzalkonium chloride (BAK)-free (TTFC) vs. latanoprost/timolol fixed combination preserved with BAK (LTFC) in open-angle glaucoma patients insufficiently controlled with latanoprost 0.005% monotherapy given once in the evening.

METHODS

The authors have conducted a prospective, observer-masked, active-controlled, cross-over, comparison study. Qualified open-angle glaucoma patients who demonstrated a latanoprost-treated morning IOP (10:00 ± 1 h) greater than 20 mmHg on two separate visits were randomized for 3 months to receive either TTFC or LTFC. Patients were then crossed over to the opposite treatment for another 3 months. At the end of the latanoprost run-in and after each 3-month therapy period patients underwent 24-h IOP monitoring in the habitual position using Goldmann applanation tonometry in the sitting position during the day (10:00, 14:00, 18:00 and 22:00) and Perkins tonometry in the supine position at night (02:00 and 06:00). Selected ocular surface parameters were evaluated after each therapy period.

RESULTS

Forty-two open-angle glaucoma patients completed the study. The mean 24-h baseline IOP on latanoprost was 21.5 ± 1.6 mmHg. Both fixed combinations significantly reduced the IOP at each time point, for the mean, peak and fluctuation of 24-h IOP compared with latanoprost monotherapy (P < 0.01). When the two fixed combinations were compared directly, TTFC provided significantly lower mean 24-h IOP (18.9 ± 2.2 mmHg) vs. LTFC (19.3 ± 2.3 mmHg) (P = 0.004) and significantly lower IOP at 18:00 (18.6 ± 2.5 vs. 19.5 ± 2.7 mmHg for LTFC) (P < 0.001). Further, TTFC demonstrated significantly better tear film break-up time (5.15 vs. 4.65 s), corneal stain (1.5 vs. 1.8) and Schirmer I test (9.9 vs. 9.2 mm) compared with LTFC after 3 months of therapy (P < 0.01 for all comparisons).

CONCLUSION

The mean 24-h IOP lowering of TTFC was statistically more significant compared to LTFC in patients insufficiently controlled with latanoprost monotherapy. Measurement of ocular surface health and tear film status favored the BAK-free TTFC compared to LTFC.

Ocular toxicity of benzalkonium chloride homologs compared with their mixtures

This study was performed to assess the in vivo ocular toxicity of benzalkonium chloride (BAK) homologs compared with commercially available BAK (BAK mixture) and to assess the ocular toxicity of BAK homolog after repeated ocular application. Rabbit eyes were examined by ophthalmology and scanning electron microscopy (SEM) after 10 applications of BAK homologs with C12 (C12-BAK) and C14 (C14-BAK) alkyl chain lengths and a BAK mixture at concentrations of 0.001% (w/v), 0.003% (w/v), 0.005% (w/v), 0.01% (w/v) and 0.03% (w/v). The ocular toxicity of C12-BAK to rabbit eyes was examined by ophthalmology and histopathology after repeated ocular application for 39 weeks. In addition, the antimicrobial activities of C12-BAK and C14-BAK against A. niger, S. aureus and P. aeruginosa were assessed. Ocular toxicity of C12-BAK was less than those of the BAK mixture and C14-BAK. No ocular toxicity was noted after ocular application of 0.01% C12-BAK to rabbits for 39 weeks. C12-BAK showed antimicrobial activities at a concentration of 0.003%. These results suggest that the use of C12-BAK to replace BAK mixture as a preservative in ophthalmic solutions should be considered in order to reduce the incidence of the corneal epithelial cell injury induced clinically by BAK.

The diurnal and nocturnal effect of travoprost with sofZia on intraocular pressure and ocular perfusion pressure

PURPOSE

To determine the 24-hour effects of travoprost with sofZia on intraocular pressure (IOP) and ocular perfusion pressure as well as the endurance of IOP lowering after last dosing.

DESIGN

Prospective, open-label study.

METHODS

Forty subjects with open-angle glaucoma or ocular hypertension were admitted to our sleep laboratory for three 24-hour sessions monitoring IOP, blood pressure (BP), and heart rate. The first baseline session occurred after medication washout or immediately after enrollment for treatment-naïve patients. A second 24-hour monitoring session was performed after 4 weeks of once-nightly treatment of travoprost with sofZia. The medication was then discontinued and a third 24-hour session was completed 60-84 hours after the last dose taken. IOP measurements were taken using a pneumotonometer every 2 hours in the sitting position during the 16-hour diurnal period and in the supine position during the 8-hour nocturnal period. Ocular perfusion pressure was defined as 2/3[diastolic BP + 1/3(systolic BP - diastolic BP)] - IOP.

RESULTS

Treatment with travoprost with sofZia significantly lowered mean diurnal and nocturnal IOP levels from baseline (diurnal 18.1 ± 3.9 to 15.3 ± 3.3 mm Hg; nocturnal 20.6 ± 3.6 to 19.4 ± 3.4 mm Hg, P < .01 for both). Once treatment was discontinued, mean IOP remained at levels significantly less than baseline during both the diurnal (16.6 ± 3.8 mm Hg) and nocturnal periods (19.4 ± 3.5 mm Hg). Mean baseline ocular perfusion pressure was significantly increased during the diurnal but not the nocturnal period (diurnal 73.7 ± 11.4 to 76.5 ± 10.3 mm Hg, P = .01; nocturnal 64.4 ± 12.6 to 64.2 ± 11.1 mm Hg, P = .67).

CONCLUSION

Travoprost with sofZia significantly lowers IOP throughout the diurnal and nocturnal periods, and increases ocular perfusion pressure in the diurnal, but not the nocturnal, period in open-angle glaucoma and ocular hypertension. The treatment effect on IOP endures for at least 84 hours after the last dose.

In vitro effects of preservative-free and preserved prostaglandin analogs on primary cultured human conjunctival fibroblast cells

PURPOSE

Long-term use of topical medication is needed for glaucoma treatment. One of the most commonly prescribed classes of hypotensive agents are prostaglandin analogs (PGs) used as both first-line monotherapy; as well as in combination therapy with other hypotensive agents. Several side effects of eye drops can be caused by preservatives. The purpose of this study was to evaluate the effects of PGs with varying concentrations of benzalkonium chloride (BAC), alternative preservatives, or no preservatives on human conjunctival fibroblast cells.

METHODS

Primary human conjunctival fibroblast cells were used in these experiments. Cells were exposed to the following drugs: BAC at different concentrations, bimatoprost 0.01% (with BAC 0.02%), latanoprost 0.005% (with BAC 0.02%), tafluprost 0.0015% with/without 0.001% BAC and travoprost 0.004% (with 0.001% Polyquad) for 15 and 30 minutes. Cell cytotoxicity was evaluated by phase-contrast microscopy to monitor morphological changes of cells, Counting Kit-8 (CCK-8) assay to cell viability, and fluorescent activated cell sorting (FACS) analysis to measure apoptosis.

RESULTS

BAC caused cell shrinkage and detachment from the plate in a dose-dependent manner. Morphological changes were observed in cells treated with bimatoprost 0.01% and latanoprost 0.005%. However, mild cell shrinkage was noted in cells treated with tafluprost 0.0015%, while a non-toxic effect was noted with travoprost 0.004% and preservative-free tafluprost 0.0015%. CCK-8 assay and FACS analysis showed all groups had a significantly decreased cell viability and higher apoptosis rate compared with the control group. However, travoprost 0.004% and preservative-free tafluprost 0.0015% showed lower cytotoxicity and apoptosis rate than other drugs.

CONCLUSIONS

This in vitro study revealed that BAC-induced cytotoxicity is dose-dependent, although it is important to emphasize that the clinical significance of toxicity differences observed among the different PGs formulations has not yet been firmly established. Alternatively preserved or preservative-free glaucoma medications seem to be a reasonable and viable alternative to those preserved with BAC.

Local toxicity of benzalkonium chloride in ophthalmic solutions following repeated applications

We performed repeated toxicity studies of benzalkonium chloride (BAK)-containing vehicles of ophthalmic solutions in monkeys and rabbits to assess the local toxicity of BAK after repeated applications on the ocular surface. Local toxicity of BAK was evaluated by toxicity studies in which a 0.01% BAK-containing vehicle was applied twice/day for 52 weeks, 4 times/day for 39 weeks, or 6 times/day for 13 weeks, or in which a 0.005% BAK-containing vehicle was applied 6 times/day for 52 weeks or twice/day for 4 weeks in monkeys. Local toxicity of BAK was also evaluated where a 0.01% BAK-containing vehicle was applied 6 times/day for 6 weeks, or a 0.005% BAK-containing vehicle was applied twice/day for 39 weeks or 8 times/day for 4 weeks in rabbits. These doses were chosen because BAK is generally used at concentrations up to 0.01% in ophthalmic solutions. The BAK-containing vehicle did not cause ophthalmological changes suggestive of irritation, allergy, or corneal damage. We also did not observe any histopathological changes in the eyeball, eyelid, lacrimal gland, and nasal cavity, with repeated applications of BAK for up to 52 weeks, up to 8 times/day, or at concentrations up to 0.01%, in monkeys and rabbits. Our results suggest that BAK in concentrations up to 0.01% in ophthalmic solution is non-toxic to the eyeball, its accessory organs, and the nasal cavity after long repeated applications.

Effects of benzalkonium chloride on THP-1 differentiated macrophages in vitro

Purpose

To characterize the effects of benzalkonium chloride (BAK) in THP-1 differentiated cells in vitro.

Methods

Macrophages were obtained after differentiation of THP-1 cells, a human monocytic leukemia cell line. Macrophages were exposed for 24 h to 33 nM (10⁻⁵%) benzalkonium chloride (BAK), 10 nM dinitrochlorobenzene (DNCB), 100 ng/mL lipopolysaccharide (LPS), 5 ng/mL tumor necrosis factor alpha (TNF-α) or phosphate buffered saline (PBS) as controls. The expression of CD11b, CD11c, CD33 and CD54 was evaluated using immunohistochemistry and flow cytometry (FCM). Phagocytosis function was analyzed using carboxylate-modified fluorescent microspheres and quantified by FCM. Migration was evaluated in cocultures with conjunctival epithelial cells. Cytokine production was detected and quantified in culture supernatants using a human cytokine array.

Results

Stimulation of THP-1-derived macrophages with a low concentration of BAK increased CD11b and CD11c expression and decreased CD33. Macrophages exposed to BAK, LPS and TNF-α had increased phagocytosis. In contrast to LPS, BAK and TNF-α increased macrophage migration. Cytokines in supernatants of macrophages exposed to BAK revealed an increased release of CCL1, CCL4/MIP-1β, TNF-α, soluble CD54/ICAM-1 and IL-1β.

Conclusion

In vitro, BAK has a direct stimulating effect on macrophages, increasing phagocytosis, cytokine release, migration and expression of CD11b and CD11c. Long-term exposure to low concentrations of BAK should be considered as a stimulating factor responsible for inflammation through macrophage activation.

Glaucoma therapy and ocular surface disease: current literature and recommendations

PURPOSE OF REVIEW

To provide an update on clinical and experimental literature for ocular surface effects of glaucoma therapy and to provide practical guidelines for ophthalmologists treating glaucoma patients with ocular surface disease (OSD).

RECENT FINDINGS

Preservatives, notably benzalkonium chloride (BAK), continue to contribute to OSD and demonstrate a variety of toxic ocular effects both in-vitro, and in animal/human studies. Recent literature frequently compares BAK with Polyquad, SofZia, and preservative-free therapies. Some clinical benefit has been demonstrated with newer BAK-free alternatives.

SUMMARY

BAK-free and preservative-free therapies are becoming available but are not always a feasible alternative. It is important to recognize different clinical manifestations of allergy and chronic inflammation and to discuss options for patients experiencing OSD.

The effect of topical pranoprofen 0.1% on the clinical evaluation and conjunctival HLA-DR expression in dry eyes

PURPOSE

To investigate the effect of topical pranoprofen 0.1% on the clinical evaluation and conjunctival human leukocyte antigen II (HLA-DR) expression in dry eyes.

METHODS

Sixty patients with dry eyes were randomized to 2 groups. Patients in group 1 received topical pranoprofen 0.1% plus topical sodium hyaluronate 0.1%; and patients in group 2 received sodium hyaluronate without pranoprofen. Ocular surface disease index (OSDI), tear &filig;lm break-up time (TBUT), Schirmer I test, ocular surface staining (OSS), and conjunctival HLA-DR expression were evaluated before treatment and at 15 and 30 days after treatment.

RESULTS

On day 15, patients in group 1 had significantly lower OSDI, OSS, and HLA-DR-positive cells compared with patients in group 2 (P < 0.01), and the TBUT was significantly longer in patients in group 1 than that of patients in group 2 (P < 0.01). On day 30, the difference between the 2 groups in OSS lost significance; however, there continued to be significant differences in the OSDI, TBUT, and HLA-DR expression between the 2 groups (P < 0.01). On days 15 and 30, the values in group 1 patients had significant improvement compared with their baseline values in terms of the above-mentioned parameters. The comparisons within group 2 did not reveal any significant differences. There was no significant effect in the Schirmer I test value in eyes of patients in group 1 or group 2 at days 15 or 30 (P > 0.05).

CONCLUSIONS

Topical pranoprofen 0.1% has a beneficial effect in reducing the ocular signs and symptoms of dry eyes and decreasing the inflammatory markers of conjunctival epithelial cells.

Cell viability score as an integrated indicator for cytotoxicity of benzalkonium chloride-containing antiglaucoma eyedrops

We evaluated the in vitro cytotoxicity of benzalkonium chloride (BAK)-containing antiglaucoma eyedrops. We prepared cell cultures of SIRC, BCE C/D-1b, RC-1, and Chang conjunctiva. The viability of cell cultures was determined using the MTT and neutral red assays. The cell viability score (CVS) was used to compare the toxicity of test solutions. %CVS50 and %CVS40/80 of each eyedrop solution were 71 and 26 for Lumigan(®) (0.002% bimatoprost with 0.005% BAK), 100 and 99 for Tapros(®) (0.0015% tafluprost, a new formula from 2010 with 0.001% BAK), 39 and -29 for 2% Trusopt(®) (2% dorzolamide with 0.0075% BAK), 28 and -43 for Xalacom(®) (latanoprost/0.5% timolol with 0.02% BAK), 88 and 66 for DuoTrav(®) (travoprost/0.5% timolol with no BAK), 36 and -35 for Cosopt(®) (2% dorzolamide/0.5% timolol with 0.0075% BAK) and 53 and -1 for Combigan(®) (0.15% brimonidin/0.5% timolol with 0.005% BAK). Only Xalacom(®) and Tapros(®) did not show an apparent decrease in %CVS as compared to the corresponding concentration of BAK. In conclusion, the cytotoxicity of tested eyedrops was dependent on BAK. Only the eyedrops containing latanoprost or tafluprost showed a reduction in the cytotoxicity of BAK.

Short-term effect of topical brinzolamide-timolol fixed combination on ocular surface of glaucoma patients

AIM

To evaluate the short-term effect of the fixed combination of brinzolamide-timolol on the ocular surface in glaucoma patients.

METHODS

This is a prospective study of 23 eyes of 23 patients with newly diagnosed glaucoma. Schirmer I test, tear break-up time (BUT) measurement, conjunctival impression cytology and central corneal thickness (CCT) measurements were performed in one of the eyes of each patients before and 4 weeks after brinzolamide-timolol fixed combination therapy. All patients were asked to answer the OSDI questionnaire form about the ocular surface symptoms at baseline and at 1 week and 4 weeks follow-up visits.

RESULTS

After brinzolamide-timolol fixed combination theraphy Schirmer I, BUT and CCT values decreased but the only statistically significant decrease was seen in BUT test (P=0.03). OSDI scores increased during the follow-up but this increase was not statistically significant (P=0.22, P=0.42 respectively). Impression cytology findings ranged from 0.78±0.42 to 0.95±0.36 according to the Nelson classification. There was no statistically significant difference between baseline and 4 weeks follow up in impression cytology grades (P=0.15).

CONCLUSION

The results of our study indicate that short-term use of brinzolamide-timolol fixed combination theraphy does not have a profound effect on ocular surface except BUT values.

Acute effects of glaucoma medications and benzalkonium chloride on pre-adipocyte proliferation and adipocyte cytotoxicity in vitro

PURPOSE

To determine and compare the short-term, in vitro effect of prostaglandin analogues (PGAs), timolol, and benzalkonium chloride (BAK) on pre-adipocyte proliferation and adipocyte cytotoxicity.

METHODS

For the proliferation assay, human primary subcutaneous pre-adipocytes were incubated in the presence of either bimatoprost (0.015%, 0.03%, 0.06%) travoprost (0.002%, 0.004%, 0.008%), latanoprost (0.0025%, 0.005%, 0.010%), tafluprost (0.00075%, 0.0015%, 0.003%), timolol maleate (0.25%, 0.5%, 1.0%), BAK (0.005%, 0.010%, 0.015%, 0.020%, 0.040%), or control of BAK vehicle. After 72 h in culture, cell numbers were determined by fluorescent assay with CellTiter-Blue(®) reagent. For the cytotoxity assay, mature human adipocytes were cultured for 72 h with the same test compounds and controls. Cell numbers were again determined in the same manner through fluorescence.

RESULTS

In the proliferation assay, all four PGA medications failed to show a statistically significant difference from BAK vehicle alone (p = 0.065-0.751). Both timolol and BAK alone demonstrated near complete inhibition of pre-adipocyte proliferation at all concentrations tested (p < 0.01 for all). In the cytotoxicity assay, all four PGAs again exerted no significant effect when compared to control (p = 0.211-0.901). Timolol and BAK again displayed near complete toxicity of adipocytes at all concentrations (p < 0.01 for all).

CONCLUSIONS

All four PGAs had similar and negligible short-term effects on pre-adipocyte proliferation and adipocyte toxicity in vitro. Timolol and BAK had profound cytotoxic effects on mature adipocytes and antiproliferative effects on pre-adipocytes in vitro. Further testing is needed to determine whether similar effects are present in vivo.

Overview of the [corrected] travoprost /timolol BAK-free fixed combination

INTRODUCTION

Glaucoma is the second leading cause of blindness globally, representing a significant public health concern. More than 60 million people are affected by glaucoma worldwide; as this population ages, the number is expected to increase. Glaucoma is a collection of heterogeneous diseases sharing common clinical characteristics. The goal of treatment is to prevent significant visual dysfunction through reduction of intraocular pressure (IOP).

AREAS COVERED

This is a review of the current literature about combination therapeutic regimens for the reduction of IOP, focusing on the risk : benefit profile of a fixed-combination therapy using travoprost and timolol.

EXPERT OPINION

Since the debut of prostaglandin analogues in the 1990s, only modest innovation has occurred in glaucoma pharmacology. A growing body of research has established that the preservative benzalkonium chloride (BAK) might not be the benign contributor expected of excipient ingredients. Thus, BAK-free treatments were developed, with the goal of IOP reduction without furthering ocular surface disease symptoms. The BAK-free travoprost/timolol combination represents an important addition to glaucoma medication options and may fill an unmet need in this therapeutic arena.

Hydrophilic coating of mitotane-loaded lipid nanoparticles: preliminary studies for mucosal adhesion

The aim of the present work was to load mitotane, an effective drug for adrenocortical carcinoma treatment, in solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC). The SLN and NLC were successfully prepared by high shear homogenization followed by hot high pressure homogenization. Formulations were composed of cetyl palmitate as the solid lipid for SLN, whereas for NLC PEGylated stearic acid was selected as solid lipid and medium chain triacylglycerols as the liquid lipid. Tween® 80 and Span® 85 were used as surfactants for all formulations. The particle size, zeta potential, polydispersity index (PI), encapsulation efficiency (EE), and loading capacity (LC) were evaluated. The SLN showed a mean particle size of 150 nm, PI of 0.20, and surface charge -10 mV, and the EE and LC could reach up to 92.26% and 0.92%, respectively. The NLC were obtained with a mean particle size of 250 nm, PI of 0.30, zeta potential -15 mV and 84.50% EE, and 0.84% LC, respectively. Hydrophilic coating of SLN with chitosan or benzalkonium chloride was effective in changing zeta potential from negative to positive values. The results suggest that mitotane was efficiently loaded in SLN and in NLC, being potential delivery systems for improving mitotane LC and controlled drug release.

Antiglaucoma drugs: The role of preservative-free formulations

Hypersensitive reactions to eyedrops are a common finding in clinical practice and represent a frequent cause of discontinuation of the therapy. Moreover, experimental and clinical studies show that long term use of topical drugs may induce ocular surface changes causing discomfort and potentially negatively affecting the compliance to the treatment as well as the success rate of filtering procedures. The exact mechanism involved and the roles of the active compound and the preservatives in inducing such detrimental effects of ophthalmic solutions are unclear. During the last years several antiglaucoma agents have been marketed as either preservative-free or benzalkonium chloride-free formulations in an attempt to reduce the adverse effects related to preservatives. This paper summarizes the body of evidence from existing studies about preservatives in antiglaucoma eyedrops, focusing on the latest compounds commercially available. A systematic review of the literature was performed. Current research is focusing not only on the efficacy of the drugs but also on their tolerability. Based on the existing data, there is a rationale to support the use of benzalkonium-free solutions whenever possible, especially in patients suffering from concomitant ocular surface diseases, experiencing local side effects and in those expected to need multiple and prolonged topical treatments.