Interactions of olopatadine and selected antihistamines with model and natural membranes

Combine therapy as a modern approach to treatment of allergic rhinitis

Allergic rhinitis (AR) is one the most common allergic diseases affecting from 10 to 40% of the population in different countries, including Russia. AR is a risk factor of bronchial asthma, other upper airway disease and may decrease patient quality of life, their productivity, increase probability of occupational traumatism, depression and anxiety. AR also presents a substantial economic burden. The rationale to use fixed dose combination of intranasal steroids and topical H1 antihistamines includes suboptimal control of symptoms by monotherapy, its complementary pharmacologic activity and the results of clinical trials. This review focused on fixed dose combination of intranasal mometasone furoate and olopataine. Double blind placebo-controlled and open clinical trials have confirmed that this combination decreased severity of nasal and ocular symptoms of seasonal and perennial AR, improved patient quality of life and had a good tolerability. Its efficacy was higher than those of monotherapy. Fast onset of action and sustainable effect on symptoms (during 1 yr) may improve adherence patients to the treatment and control of symptoms of AR.

Discovery to Launch of Anti-allergy (Emadine; Patanol/Pataday/Pazeo) and Anti-glaucoma (Travatan; Simbrinza) Ocular Drugs, and Generation of Novel Pharmacological Tools Such as AL-8810

The eye and eyesight are exquistly designed and are precious, and yet we often take them for granted. Good vision is critical for our long-term survival and for humanity's enduring progress. Unfortunately, since ocular diseases do not culminate in life-and-death scenarios, awareness of the plight of millions of people suffering from such eye ailments is not publicized as other diseases. However, losing eyesight or falling victim to visual impairment is a frightening outlook for most people. Glaucoma, a collection of chronic optic neuropathies, of which the most prevalent form, primary open-angle glaucoma (POAG), is the second leading cause of irreversible blindness. POAG currently afflicts >70 million people worldwide and is an insidious, progressive, silent thief of sight that is asymptomatic. On the other hand, allergic conjunctivitis (AC), and the associated rhinitis ("hay-fever"), frequently victimizes a huge number of people worldwide, especially during seasonal changes. While not life-threatening, sufferers of AC soon learn the value of drugs to treat their signs and symptoms of AC as they desire rapid relief to overcome the ocular itching/pain, redness, and tearing AC causes. Herein, I will describe the collective efforts of many researchers whose industrious, diligent, and dedicated team work resulted in the discovery, biochemical/pharmacological characterization, development and eventual launch of drugs to treat AC (e.g., olopatadine [Patanol/Pataday/Pazeo] and emedastine [Emedine]), and for treating ocular hypertension and POAG (e.g., travoprost [Travatan ] and Simbrinza). This represents a personal perspective.

Efficacy of histamine H1 receptor antagonists azelastine and fexofenadine against cutaneous Leishmania major infection

Current drug therapies for cutaneous leishmaniasis are often difficult to administer and treatment failure is an increasingly common occurrence. The efficacy of anti-leishmanial therapy relies on a combination of anti-parasite activity of drugs and the patient's immune response. Previous studies have reported in vitro antimicrobial activity of histamine 1-receptor antagonists (H1RAs) against different pathogens. We used an ex vivo explant culture of lymph nodes from mice infected with Leishmania major to screen H1RAs compounds. Azelastine (AZ) and Fexofenadine (FX) showed remarkable ex vivo efficacy (EC50 = 0.05 and 1.50 μM respectively) and low in vitro cytotoxicity yielding a high therapeutic index. AZ significantly decreased the expression of H1R and the proinflammatory cytokine IL-1ẞ in the ex vivo system, which were shown to be augmented by histamine addition. The anti-leishmanial efficacy of AZ was enhanced in the presence of T cells from infected mice suggesting an immune-modulatory mechanism of parasite suppression. L. major infected BALB/c mice treated per os with FX or intralesionally with AZ showed a significant reduction of lesion size (FX = 69%; AZ = 52%). Furthermore, there was significant parasite suppression in the lesion (FX = 82%; AZ = 87%) and lymph nodes (FX = 81%; AZ = 36%) with no observable side effects. AZ and FX and potentially other H1RAs are good candidates for assessing efficacy in larger studies as monotherapies or in combination with current anti-leishmanial drugs to treat cutaneous leishmaniasis.

Biomimetic contact lenses eluting olopatadine for allergic conjunctivitis

Combination of the ability of contact lenses (CLs) to act as a physical barrier against airborne antigen and to serve as a sustained depot of antihistaminic drugs may improve the efficiency of treatments of some ocular allergic diseases. The aim of this work was to develop CLs that exhibit affinity to olopatadine by mimicking the composition of the natural H1-receptor for which olopatadine behaves as a selective antagonist. Functional monomers that match the chemical groups of the receptor and application of the molecular imprinting technology led to hydrogels able to load high amounts of olopatadine and to sustain the release once in contact with lachrymal fluid. Optimized hydrogels prepared with acrylic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid and benzylmethacrylate as functional monomers provided in few hours olopatadine concentrations similar to those of commercially available eye drops but the levels could be sustained for a whole day, demonstrating their efficacy. Olopatadine-loaded CLs successfully passed the HET-CAM test of ocular irritancy and showed good compatibility with mast cells. They were able to inhibit the release of histamine and TNF-α from sensitized mast cells, proving their potential application in preventing and treating allergic conjunctivitis.

STATEMENT OF SIGNIFICANCE

Contact lenses (CLs) with affinity for antiallergic drugs may constitute an advantageous alternative to eye drops in management of ocular allergies for both contact lens wearers and patients who eventually use neutral CLs as therapeutic platforms. The present work represents a step forward in the state of the art of drug-CL combo products by (i) mimicking the composition of the human receptor of the drug, (ii) exploring combinations of functional monomers that include a monomer (2-acrylamido-2-methyl-1-propanesulfonic acid; AMPSA) with a strong acid group (pKa<4) able to enhance the interaction of the network with olopatadine in the saline environment of the lachrymal fluid, and (iii) analysing in detail the antihistamic effects provided by olopatadine released from the CLs on sensitized mast cells.

Efficacy and safety of olopatadine hydrochloride 0.77% in patients with allergic conjunctivitis using a conjunctival allergen-challenge model

Background

Symptom relief for the duration of 24 hours after treatment would benefit patients with allergic conjunctivitis.

Objective

To compare the safety and efficacy of olopatadine 0.77% with vehicle or olopatadine 0.2% in patients with allergic conjunctivitis in a conjunctival allergen-challenge clinical study.

Patients and methods

In this Phase III, multicenter, double-masked, parallel-group, randomized trial, patients with allergic conjunctivitis received olopatadine 0.77%, its vehicle, or olopatadine 0.2%, administered once at visits 3A (day 0), 4A (day 14 ±2), and 5 (day 21 +3). Allergic conjunctivitis-associated sign and symptom assessments included ocular itching, conjunctival redness, total redness, chemosis, and tearing scores. Adverse events and ocular safety parameters were also assessed.

Results

A total of 202 qualifying patients were randomized. Olopatadine 0.77% was superior (P<0.001) to vehicle for treatment of ocular itching at 3, 5, and 7 minutes postchallenge at onset of action and 16- and 24-hour duration of action. Conjunctival redness mean scores were significantly lower for olopatadine 0.77% versus vehicle at all three post-conjunctival allergen-challenge time points: onset (−1.52 to −1.48; P<0.001), 16 hours (−1.50 to −1.38; P<0.01), and 24 hours (−1.58 to −1.38; P<0.05). At 24 hours, olopatadine 0.77% was superior to olopatadine 0.2% at all three postchallenge time points for ocular itching (P<0.05), conjunctival redness (P<0.05), and total redness (P<0.05). No clinically relevant differences in safety parameters or adverse events were observed between the treatment groups.

Conclusion

Olopatadine 0.77% is superior to both its vehicle and olopatadine 0.2% for the treatment of allergen-mediated ocular itching and conjunctival redness. Ocular itching symptom relief is maintained over 24 hours, supporting once-daily dosing and demonstrating a comparable safety profile to olopatadine 0.2%.

Rhamnolipids elicit the same cytotoxic sensitivity between cancer cell and normal cell by reducing surface tension of culture medium

Biosurfactant rhamnolipids have been claimed to show biological activities of inhibiting the proliferation of cancer cells. In this study, the cytotoxicity of rhamnolipids was examined on four cancer cells (HepG2, Caco-2, Hela, MCF-7 cells) and two normal cells (HK-2 cell, primary hepatocyte). Interestingly, both cancer cells and normal cells exhibited similar sensitivities to the addition of rhamnolipids in culture medium, and the cytotoxicity was largely attenuated by the presence of fetal bovine serum (FBS) in culture medium. In correlation of the mono-/di-rhamnolipid cytotoxicity with the surface tension of culture medium, it was found that rhamnolipids triggered cytotoxicity whenever the surface tension of culture medium decreased below 41 mN/m irrespective of the FBS content in culture medium, cell line, or rhamnolipid congener. Similarly, each chemical surfactant (Tween-80, sodium dodecyl sulfate, and sodium dodecyl benzene sulfonate) could cause cytotoxicity on HepG2 cells whenever its addition made the surface tension under 41 mN/m in culture medium with or without the presence of FBS. It seems that rhamnolipids, like chemical surfactants, exhibited cytotoxicity by reducing the surface tension of culture medium rather than by changing its specific molecular structure, which had no selection on tumor cells. This study could offer helps to correct the misleading biological activity of rhamnolipids and to avoid the possible large wastes of time and expenses on developing the applications in antitumor drugs.

Effect of azelastine on cardiac repolarization of guinea-pig cardiomyocytes, hERG K⁺ channel, and human L-type and T-type Ca²⁺ channel

Azelastine is a second generation histamine H₁-receptor antagonist used as an anti-asthmatic and anti-allergic drug that can induce QT prolongation and torsades de pointes. We investigated the acute effects of azelastine on human ether-a-go-go-related gene (hERG) channels, action potential duration (APD), and L-type (I(Ca,L)) and T-type Ca²⁺ current (I(Ca,T)) to determine the electrophysiological basis for its proarrhythmic potential. Azelastine increased the APD at 90% of repolarization concentration dependently, with an IC₅₀ of 1.08 nM in guinea-pig ventricular myocytes. We examined the effects of azelastine on the hERG channels expressed in Xenopus oocytes and HEK293 cells using two-microelectrode voltage-clamp and patch-clamp techniques. Azelastine induced a concentration-dependent decrease of the hERG current amplitude at the end of the voltage steps and tail currents. The IC₅₀ for the azelastine-induced block of the hERG currents expressed in HEK293 cells was 11.43 nM, while the drug inhibited I(Ca,L) and I(Ca,T) with IC₅₀ values of 7.60 and 26.21 μM, respectively. The S6 domain mutations, Y652A partially attenuated and F656A abolished hERG current block. These results suggest that azelastine is a potent blocker of hERG channels rather than I(Ca,L) or I(Ca,T), providing molecular mechanisms for the arrhythmogenic side effects during the clinical administration of azelastine.

Membrane permeability alteration of some bacterial clinical isolates by selected antihistaminics

Several antihistaminics possess antibacterial activity against a broad spectrum of bacteria. However, the exact mechanism of such activity was unclear. Hence, the aim of this study is to investigate their mechanism of antibacterial activity especially their effect upon the permeability of the bacterial cytoplasmic membrane. The effects of azelastine, cetirizine, cyproheptadine and diphenhydramine were studied using Gram-positive and Gram-negative multiresistant clinical isolates. Leakage of 260 and 280 nm UV-absorbing materials was detected upon treatment with the tested antihistaminics; indicative of membrane alteration. Using an artificial membrane model, cholesterol-free negatively-charged unilamellar liposomes, confirmed the effect of antihistaminics upon the membrane permeability both by showing an apparent membrane damage as observed microscopically and by detection of leakage of preloaded dye from the liposomes colorimatrically. Moreover, examination of the ultrastructure of cells treated with azelastine and cetirizine under the transmission electron microscope substantiated the detected abnormalities in the cell wall and membrane. Furthermore, the effect of pretreating certain isolates for both short and long periods with selected antihistaminics was followed by the viable count technique. Increased vulnerability towards further exposure to azelastine was observed in cells pretreated with azelastine for 2 days and those pretreated with azelastine or cetrizine for 30 days.

In vitro antibacterial activity of some antihistaminics belonging to different groups against multi-drug resistant clinical isolates

Antihistaminics are widely used for various indications during microbial infection. Hence, this paper investigates the antimicrobial activities of 10 antihistaminics belonging to both old and new generations using multiresistant Gram-positive and Gram-negative clinical isolates. The bacteriostatic activity of antihistaminics was investigated by determining their MIC both by broth and agar dilution techniques against 29 bacterial strains. Azelastine, cyproheptadine, mequitazine and promethazine were the most active among the tested drugs. Diphenhydramine and cetirizine possessed weaker activity whereas doxylamine, fexofenadine and loratadine were inactive even at the highest tested concentration (1 mg/ml). The MIC of meclozine could not be determined as it precipitated with the used culture media. The MBC values of antihistaminics were almost identical to the corresponding MIC values. The bactericidal activity of antihistaminics was also studied by the viable count technique in sterile saline solution. Evident killing effects were exerted by mequitazine, meclozine, azelastine and cyproheptadine. Moreover, the dynamics of bactericidal activity of azelastine were studied by the viable count technique in nutrient broth. This activity was found to be concentration-dependant. This effect was reduced on increasing the inoculum size while it was increased on raising the pH. The post-antimicrobial effect of 100 μg/ml azelastine was also determined and reached up to 3.36 h.

Treatment of allergic conjunctivitis with olopatadine hydrochloride eye drops

Olopatadine hydrochloride exerts a wide range of pharmacological actions such as histamine H₁ receptor antagonist action, chemical mediator suppressive action, and eosinophil infiltration suppressive action. Olopatadine hydrochloride 0.1% ophthalmic solution (Patanol^®) was introduced to the market in Japan in October 2006. In a conjunctival allergen challenge (CAC) test, olopatadine hydrochloride 0.1% ophthalmic solution significantly suppressed ocular itching and hyperemia compared with levocabastine hydrochloride 0.05% ophthalmic solution, and the number of patients who complained of ocular discomfort was lower in the olopatadine group than in the levocabastine group. Conjunctival cell membrane disruption was observed in vitro in the ketotifen fumarate group, epinastine hydrochloride group, and azelastine hydrochloride group, but not in the olopatadine hydrochloride 0.1% ophthalmic solution group, which may potentially explain the lower discomfort felt by patients on instillation. Many other studies in humans have revealed the superiority of olopatadine 0.1% hydrochloride eye drops to several other anti-allergic eye drops. Overseas, olopatadine hydrochloride 0.2% ophthalmic solution for a once-daily regimen has been marketed under the brand name of Pataday^®. It is expected that olopatadine hydrochloride ophthalmic solutions may be used in patients with a more severe spectrum of allergic conjunctival diseases, such as vernal keratoconjunctivitis or atopic keratoconjunctivitis, in the near future.

Comparison of effects of alcaftadine and olopatadine on conjunctival epithelium and eosinophil recruitment in a murine model of allergic conjunctivitis

Background:

Antihistamines constitute the first line of therapy for allergic conjunctivitis, and are safe and effective in relieving the signs and symptoms of ocular allergy. Despite this, they are less effective than some other drugs in relieving delayed symptoms of allergic conjunctivitis. Recent evidence suggests that changes in the conjunctival epithelium may underlie aspects of delayed reactions. In this study we compared two antihistamines, olopatadine and alcaftadine, for their ability to modify epithelial cell changes associated with allergic conjunctivitis at time points selected to reflect late-phase reactions.

Methods:

Studies employed a modified conjunctival allergen challenge model. Sensitized mice were challenged with topical allergen with or without drug treatments. Treatment groups were assayed for acute-phase (15 minutes) and delayed-phase (24 hours) responses. Groups were scored for allergy symptoms (redness, itch, tearing, and edema) and for conjunctival mast cell numbers. Delayed-phase groups were also examined for eosinophil numbers and for tight junctional protein expression.

Results:

Olopatadine-treated and alcaftadine-treated animals had similar efficacy profiles and mast cell numbers, suggesting both were effective at ameliorating symptoms of the acute phase. In contrast, alcaftadine-treated animals had significantly lower conjunctival eosinophil infiltration than either controls or olopatadine-treated animals. Allergen challenge caused a significant decrease in expression of the junctional protein, ZO-1, and this decrease was prevented by alcaftadine but not by olopatadine.

Conclusion:

Alcaftadine displays therapeutic properties beyond its antihistamine action. These include an ability to reduce conjunctival eosinophil recruitment, and a protective effect on epithelial tight junction protein expression.

Management of allergic conjunctivitis: an evaluation of the perceived comfort and therapeutic efficacy of olopatadine 0.2% and azelastine 0.05% from two prospective studies

PURPOSE

Results from 2 patient-reported outcome studies of allergic conjunctivitis sufferers who used olopatadine 0.2% and azelastine 0.05% are analyzed.

METHODS

The PACE (Pataday Allergic Conjunctivitis Evaluation) multi-center, prospective, open-label study examined patient perceptions of olopatadine 0.2% once daily (qd) and previous twice daily (bid) allergic conjunctivitis medications via questionnaire in allergic conjunctivitis sufferers who had previously used bid medication and then initiated olopatadine. A second conjunctival antigen challenge (CAC) study evaluated comfort of 4 allergic conjunctivitis medications.

RESULTS

Forty-nine patients from the PACE study (N = 125) with prior azelastine use were examined. Significantly more patients rated themselves "very satisfied" with current olopatadine use compared with past azelastine use on drop comfort (p < 0.0001), speed of relief (p = 0.0004), and overall satisfaction (70% vs 16%, p < 0.0001). Significantly more patients reported olopatadine "very effective" against swelling compared with azelastine (47% vs 8%, p = 0.0404). In the CAC study (N = 36), data from olopatadine (n = 8), azelastine (n = 9) and placebo (N = 36) groups were reported. Olopatadine was rated significantly more comfortable than azelastine upon instillation (p = 0.0223), at 30 seconds (p = 0.0479), and at 1 minute after instillation (p = 0.0240).

CONCLUSION

In the reported studies, olopatadine 0.2% qd was more comfortable than azelastine 0.05% and preferred by patients with allergic conjunctivitis by a ratio of 4:1.

Urban eye allergy syndrome: a new clinical entity?

BACKGROUND

A significant number of patients present with conjunctivitis that is not strictly speaking of allergic, infectious, or dry eye origin. Patients affected by this pseudo-allergic form of vasomotor or idiopathic conjunctivitis usually live in urban polluted areas and may be affected by a new clinical entity called the 'urban eye allergy syndrome'.

SCOPE

To identify the incidence, pathogenesis and therapeutic response of this condition by collecting from the literature experimental evidence on the relationship between air pollution, allergy, and conjunctival disease.

FINDINGS

Allergen susceptibility might be increased in areas with increased air pollutants. Both allergens and pollutants can directly initiate specific and nonspecific mucosal inflammation through several interweaving mechanisms.

CONCLUSIONS

The present commentary introduces the concept of 'urban eye allergy syndrome' discussing inter-actions between air pollutants and pollens, the increase of allergic signs and symptoms by pollutants, the prevalence of urban allergy, preliminary data from a single restricted geographical area, and proposed mechanisms of action.

Efficacy of once-daily olopatadine 0.2% ophthalmic solution compared to twice-daily olopatadine 0.1% ophthalmic solution for the treatment of ocular itching induced by conjunctival allergen challenge

Olopatadine 0.1% (Patanol) and olopatadine 0.2% (Pataday) ophthalmic solutions are topical ocular anti-allergic agents with antihistaminic and mast cell stabilizing properties. The efficacy of two doses of olopatadine 0.1% was compared to one dose of olopatadine 0.2% in the prevention of ocular itching associated with allergic conjunctivitis over 24 hours. This double-masked conjunctival allergen challenge (CAC) study found no significant difference in the mean itching scores between two drops of olopatadine 0.1% and one drop of olopatadine 0.2%. Both showed significant activity at the 24-hour time point and were statistically superior to placebo. No adverse events occurred while on drug therapy.

Ocular anti-allergic compounds selectively inhibit human mast cell cytokines in vitro and conjunctival cell infiltration in vivo

BACKGROUND

Conjunctival mast cells (MCs) are important effector cells in seasonal allergic conjunctivitis, via histamine and cytokine secretion. Several new anti-allergic eye drops stabilize MCs and block histamine receptors, but their anti-inflammatory effects are unclear.

OBJECTIVE

Anti-allergic drugs were compared for their anti-inflammatory effects in an in vitro model of human MC activation and in an experimental murine model of allergic conjunctivitis.

METHODS

Human cord blood stem cell-derived (CBMC) and conjunctival biopsy-derived MCs were stimulated via FcepsilonRI, degranulation and histamine release were assayed at 1 h and cytokine secretion at 24 h using multiplex arrays. Mice sensitized to short ragweed pollen were given anti-allergics topically before allergen challenge, and conjunctival immuno-staining was performed at 24 h.

RESULTS

After a 1 h stimulation, 80% of the CBMC had degranulated and secreted histamine (27.9+/-4.7 ng/10(6) cells; P<0.05). Pre-treatment by all drugs significantly reduced histamine and TNF-alpha, whereas IL-5, IL-8, IL-10 and TNF-beta profiles were differentially decreased. For conjunctival biopsy-derived cultures (n=11), FcepsilonR1 stimulation increased histamine, TNF-alpha, TNF-beta, IL-5 and IL-8 levels and the production of IL-5, IL-6 (P<0.05), histamine and IL-8 (P<0.01) was inhibited by epinastine. In vivo, epinastine and olopatadine pre-treatment significantly reduced the clinical scores and eosinophil numbers (n=6; P<0.05) while epinastine also reduced neutrophils (P<0.02).

CONCLUSION

Differential effects on MC cytokine inhibition were observed, with epinastine inhibiting MC secretion of IL-5, IL-8, IL-10 and conjunctival neutrophil infiltration. The anti-allergic drugs have anti-histamine and mast-cell stabilizing properties but might differ in clinical improvement depending on the individual and the cytokines involved.

Efficacy and comfort of olopatadine 0.2% versus epinastine 0.05% ophthalmic solution for treating itching and redness induced by conjunctival allergen challenge

BACKGROUND

Olopatadine 0.2% (Pataday, Alcon Laboratories Inc., Fort Worth, Texas, USA) and epinastine 0.05% (Elestat, Inspire Pharmaceuticals, Inc., Durham, NC, USA) are topical ocular anti-allergic agents. Both are H(1) antihistamine/mast cell stabilizers indicated for the treatment of ocular itching associated with allergic conjunctivitis.

OBJECTIVE

To compare the efficacy and comfort of olopatadine 0.2% with epinastine 0.05%, in the prevention of ocular itching associated with allergic conjunctivitis following conjunctival allergen challenge (CAC).

RESEARCH DESIGN AND METHODS

This was a 7 week, four visit, double-masked, randomized, placebo-controlled CAC study. Visit 1 screened subjects for positive ocular allergic responses and Visit 2 confirmed those responses. At Visit 3, 92 subjects were randomized into one of four treatment groups to receive one drop of study medication in each eye: (1) olopatadine 0.2%/placebo, (2) epinastine 0.05%/placebo, (3) olopatadine 0.2%/epinastine 0.05%, (4) placebo/placebo. Subjects were challenged 12 h after drop instillation to evaluate duration of action. At Visit 4, subjects were challenged 5 min after drop instillation to evaluate onset of action. Drop comfort was assessed at Visit 4. MAIN OUTCOME MEASURES;

RESULTS

This article focuses on the results of the onset-of-action challenge (Visit 4). At Visit 4, ocular itching was assessed at 3, 5, and 7 min and redness was assessed at 7, 15, and 20 min post-challenge. Drop comfort was assessed upon instillation, at 30s, and at 1, 2, and 5 min post-instillation. Olopatadine 0.2%-treated eyes exhibited significantly lower mean ocular itching scores versus epinastine 0.05%-treated eyes at 5 (p = 0.024) and 7 min (p = 0.003) post-challenge. Olopatadine 0.2%-treated eyes exhibited significantly lower mean redness scores versus epinastine 0.05%-treated eyes at all time points post-challenge (ciliary: p < or = 0.013, conjunctival: p < or = 0.015, episcleral: p < or = 0.006). Olopatadine 0.2% was rated as significantly more comfortable than epinastine 0.05% at 1 min post-drop instillation (p = 0.003). All adverse events were non-serious and unrelated to study medication. Although the CAC model reproduces allergic responses that are not environmentally-induced, patients experience varying severities of responses as are seen in real-world situations.

CONCLUSION

Olopatadine 0.2% was superior to epinastine 0.05% in preventing ocular itching and redness at onset when induced by the CAC model.

Olopatadine attenuates the enhancement of capsaicin-evoked substance P release by bradykinin from cultured dorsal root ganglion neurons

Olopatadine, a second-generation antihistamine, has recently been suggested to have an inhibitory effect on the tachykinin release from guinea-pig tracheobronchial smooth muscle preparation. In the present study, using a highly sensitive radioimmunoassay for substance P, we observed that olopatadine attenuated the enhancement of capsaicin-induced substance P release by bradykinin with an IC(50) value of 12.5 microM, without any inhibitory effect on the substance P release induced by capsaicin, potassium or bradykinin from cultured dorsal root ganglion neurons. These data suggest that olopatadine may therefore be involved in the bradykinin-induced sensitization of the transient receptor potential vanilloid 1 in cultured dorsal root ganglion neurons.

Efficacy and response with olopatadine versus epinastine in ocular allergic symptoms: A post hoc analysis of data from a conjunctival allergen challenge study

OBJECTIVES

This post hoc analysis used data from a previous study to more precisely evaluate the efficacy of olopatadine hydrochloride and epinastine hydrochloride in alleviating various levels of severity of ocular itching and conjunctival redness and to determine whether there were any significant differences in the number of responders to treatment.

METHODS

The original study was a randomized, double-masked allergen challenge comparison assessment. Adult patients with allergic conjunctivitis were screened (visits 1 and 2); those who exhibited positive allergic reactions at both visits were randomized to 1 of 3 groups. olopatadine/epinastine, olopatadine/placebo, or epinastine/placebo. At visit 3, each eye was treated with study medication, and then challenged with allergen. Itching, redness, and chemosis assessments were recorded. For the present post hoc analysis, each eye in the olopatadine/epinastine group was separately classified at each time point, based on the pretreatment severity of their symptom (itching) and sign (conjunctival redness) scores, as moderate, moderate/severe, or severe. Data were analyzed to determine responders (eyes with itching and/or conjunctival redness scores of 0 [none]).

RESULTS

Of 96 patients screened, 66 were randomized to treatment (36 women, 30 men; mean age, 44.38 years [range, 20-71 years]). Olopatadine-treated eyes exhibited lower mean itching scores than epinastine-treated eyes in the moderate/severe and severe groups at all 3 time points (3, 5, and 7 minutes), with significance in the moderate/severe group at 5 minutes (P = 0.05) and in the severe group at 5 and 7 minutes (P = 0.017 and P = 0.02, respectively). Olopatadine-treated eyes had mean conjunctival redness scores similar to epinastine-treated eyes in all severity groups at all time points (10, 15, and 20 minutes) except in the severe group at 10 minutes (P = 0.03). On response analysis, for itching, the proportion of responders was significantly greater in the olopatadine group versus the epinastine group 7 minutes after challenge (27 [50.9%] vs 14 [26.4%]; P = 0.016). For conjunctival redness, the proportion of responders was significantly greater with olopatadine treatment versus epinastine treatment at 15 and 20 minutes after challenge (15 minutes, 12 [22.6%] vs 1 [1.9%] [P = 0.002]; 20 minutes, 10 [18.9%] vs 1 [1.9%] [P = 0.008]).

The combined luminol/isoluminol chemiluminescence method for differentiating between extracellular and intracellular oxidant production by neutrophils

To address the question why isoluminol, but not luminol, failed to detect oxidants produced intracellularly, differences between these luminophores were investigated with respect to physicochemical parameters and the character of chemiluminescence signal. Our results showed the isoluminol molecule to be more polar, more hydrophilic and possessing lower ability to form intramolecular bonds than the luminol molecule. Therefore, isoluminol: (i) only slightly pervaded biological membranes; (ii) depended essentially on extracellular peroxidase; (iii) did not produce chemiluminescence in the presence of extracellular scavengers; and (iv) it could be considered a specific detector of extracellular radicals. On the other hand, the physicochemical parameters of luminol and partial resistance of its chemiluminescence to the effect of extracellular inhibitors proved the lipo/hydrophilic character of this luminophore and thus its ability to interact with radicals both outside and inside of cells. The luminol chemiluminescence measured in the presence of extracellular scavengers and the isoluminol chemiluminescence were used with the intention to differentiate the effects of two antihistamine drugs on intra- and extracellular radical formation. In activated human neutrophils, brompheniramine inhibited the extracellular and potentiated the intracellular part of chemiluminescence signal, whereas a reducing effect of loratadine was observed in both compartments.

Effects of radial shock waves on membrane permeability and viability of chondrocytes and structure of articular cartilage in equine cartilage explants

OBJECTIVE

To investigate in vitro effects of radial shock waves on membrane permeability, viability, and structure of chondrocytes and articular cartilage.

SAMPLE POPULATION

Cartilage explants obtained from the third metacarpal and metatarsal bones of 6 horses.

PROCEDURE

Equine cartilage was subjected to radial shock waves and then maintained as explants in culture for 48 hours. Treatment groups consisted of a negative control group; application of 500, 2,000, and 4,000 impulses by use of a convex handpiece (group A); and application of 500, 2,000, and 4,000 impulses by use of a concave handpiece (group B). Effects on explant structure were evaluated by use of environmental scanning electron microscopy (ESEM). Membrane permeability was determined by release of lactate dehydrogenase (LDH). Chondrocyte viability was assessed by use of vital cell staining. Comparisons of LDH activity and nonviable cell percentages were performed by ANOVA.

RESULTS

Cell membrane permeability increased significantly after application of 2,000 and 4,000 impulses in groups A and B. A significant decrease in cell viability was observed for application of 4,000 impulses in explants of group A. There was no detectable damage to integrity of cartilage explants observed in any treatment group by use of ESEM.

CONCLUSIONS AND CLINICAL RELEVANCE

Radial shock waves do not appear to structurally damage articular cartilage but do impact chondrocyte viability and membrane permeability. Caution should be exercised when extremely high periarticular pulse doses are used until additional studies can determine the long-term outcome of these effects and appropriate periarticular treatment regimens can be validated.

Mast cell stabilization and anti-histamine effects of olopatadine ophthalmic solution: a review of pre-clinical and clinical research

BACKGROUND

Histamine receptor activation and degranulation of mast cells are the mechanisms by which the ocular itching, hyperemia, chemosis, eyelid swelling, and tearing of seasonal allergic conjunctivitis are induced. Some of the topical solutions available as anti-allergy therapies are intended to interfere with these mechanisms, and the body of research regarding the capabilities of these therapeutic molecules continues to expand.

OBJECTIVE

To review the currently available literature regarding one topical ophthalmic anti-allergy agent, olopatadine (Patanol), and its anti-histaminic and mast cell stabilizing actions, both in pre-clinical and clinical settings.

DESIGN AND METHODS

Relevant research of laboratory, animal model, and clinical trial studies performed using olopatadine was reviewed. MEDLINE literature searches were conducted and supplemented by additional reports which furthered relevant discussion or were necessary to verify the information resulting from original searches.

RESULTS

Olopatadine demonstrates unique properties both pre-clinically and clinically which differentiate it from other therapeutic molecules in its class of dual action mast cell stabilizer/anti-histamine. Its non-perturbation of cell membranes, human conjunctival mast cell stabilization in vivo and in vitro, and superior efficacy as compared to other topical anti-allergic medications including mast cell stabilizers, anti-histamines, and dual action agents, all contribute to olopatadine's profile.

CONCLUSIONS

Peer-reviewed literature suggests that olopatadine is clinically superior to the other anti-allergic molecules because of its strong anti-histaminic qualities and its unique ocular mast cell stabilizing properties.

Roles of histamine and its receptors in allergic and inflammatory bowel diseases

Mast cell has a long history of being recognized as an important mediator-secreting cell in allergic diseases, and has been discovered to be involved in IBD in last two decades. Histamine is a major mediator in allergic diseases, and has multiple effects that are mediated by specific surface receptors on target cells. Four types of histamine receptors have now been recognized pharmacologically and the first three are located in the gut. The ability of histamine receptor antagonists to inhibit mast cell degranulation suggests that they might be developed as a group of mast cell stabilizers. Recently, a series of experiments with dispersed colon mast cells suggested that there should be at least two pathways in man for mast cells to amplify their own activation-degranulation signals in an autocrine or paracrine manner. In a word, histamine is an important mediator in allergic diseases and IBD, its antagonists may be developed as a group of mast cell stabilizers to treat these diseases.

A review of the use of olopatadine in allergic conjunctivitis

Ocular allergies are very common and range in intensity from mild, self-resolving, acute conditions to serious, chronic disease that can severely affect vision. The vast majority of sufferers experience relatively mild symptoms, which are often seasonal in nature. Treatments should be simple, comfortable and very safe. They should be able to respond to an ongoing attack but also provide long-term relief from symptoms. Mast cell degranulation is central to all forms of ocular allergic disease and so treatment has concentrated on preventing this process or antagonizing the effects of the primary mediator, histamine. Olopatadine is a relatively new selective H1 antagonist that has mast cell stabilizing properties and has been shown to affect release of TNFalpha and various cytokines from conjunctival epithelial cells. This paper reviews the local ocular use of olopatadine and discusses the place of the drug in the treatment of allergic eye disease.

Ocular allergy treatment comparisons: azelastine and olopatadine

Azelastine hydrochloride 0.05% and olopatadine hydrochloride 0.1% are topical ocular allergy treatments that have demonstrated multiple pharmacologic actions, including antihistamine, mast cell stabilization, and inhibition of proinflammatory mediators. In this article, the mechanisms of action, efficacy, and tolerability of these two agents on ocular signs and symptoms are examined. By studying the various target sites of drug action, an enhanced clinical response algorithm of these topical ocular agents can be implemented to maximize the response for patients suffering from ocular allergy.

A review of olopatadine for the treatment of ocular allergy

Ocular allergy affects > 20% of the general population and many therapeutic preparations are available to individuals experiencing the most common forms--seasonal and perennial allergic conjunctivitis. 0.1% Olopatadine topical ophthalmic solution is currently approved for the treatment of allergic signs and symptoms in patients > or = 3 years of age. Olopatadine is available in Europe as Opatanol) and in > 30 other countries as Patanol. It inhibits mast cell degranulation and antagonises histamine receptors to manage the itching, redness, chemosis, tearing and lid swelling of the ocular allergic reaction, and its mast cell stabilising ability has been demonstrated both in vitro (using human conjunctival mast cells) and in vivo (human clinical experience). This article reviews both the laboratory and clinical information available on olopatadine, prefaced by a discussion of the current understanding of the ocular allergic reaction and followed by the future implications for this compound. Both laboratory and clinical studies have established the efficacy, safety and comfort of olopatadine in several study design models and comparisons to other antiallergy medications. The application of olopatadine, specifically in the management of lid swelling, an allergic sign recalcitrant to therapy and nasal allergic symptoms has also been established. In the future, a new formulation containing 0.2% olopatadine exhibits a duration of action up to 24 h, supporting once-daily dosing.

Efficacy and comfort of olopatadine versus ketotifen ophthalmic solutions: a double-masked, environmental study of patient preference

BACKGROUND

Ocular allergies cause itching, redness, chemosis, tearing, and swelling of the eyelids in sensitized individuals. The options available for treatment of ocular allergy include olopatadine 0.1% (Opatanol; Patanol [US]) and ketotifen 0.025% (Zaditen; Zaditor [US]). Patient preference for an eye drop can often be a primary factor in determining the level of compliance and satisfaction with any given therapy.

OBJECTIVE

This study sought patient perspective on eye drop efficacy in controlling signs and symptoms of allergic conjunctivitis and eye drop comfort. Also evaluated were the factors considered by patients when making decisions of preference.

METHODS

One hundred patients with previous history and current symptoms of seasonal or perennial allergic conjunctivitis were enrolled at two centers (Athens, Greece, N = 50; Padova, Italy, N = 50) for this two visit, double-masked study. Qualified patients received two masked bottles of medication (one olopatadine, one ketotifen) and were asked to use both medications as needed over the course of four weeks, but not to exceed usage of two drops of medication per eye per day. At the second visit, patients answered five questions comparing the two masked medications in terms of preference, drop comfort, and efficacy in treatment of signs and symptoms. Patients also defined the factors upon which they based these decisions.

RESULTS

A significantly greater percentage of patients (81%) selected olopatadine when asked which medication they preferred; which they found more comfortable; which they found more efficacious in reducing symptoms of allergy; and which they would select if visiting the doctor's office (P < 0.0001). Seventy-six percent (76%) of patients considered both efficacy and comfort when making their preference decisions (P < 0.0001). No adverse events were volunteered or elicited.

CONCLUSION

In this study, patients preferred to use the anti-allergy eye drop olopatadine over ketotifen after using both drops and evaluating relative efficacy and comfort during the course of four weeks. A significantly greater percentage of the patients preferred to use olopatadine during the study period, found it more efficacious and comfortable, and would select olopatadine if visiting their doctor's office during allergy season.

Clinical efficacy of olopatadine vs epinastine ophthalmic solution in the conjunctival allergen challenge model

BACKGROUND

Olopatadine hydrochloride 0.1% ophthalmic solution (Patanol) and epinastine hydrochloride 0.05% ophthalmic solution (Elestat) are two topical antiallergic agents. Olopatadine is indicated for the treatment of the signs and symptoms of allergic conjunctivitis that include itching, redness, tearing, lid swelling, and chemosis. Epinastine is indicated for the prevention of itching associated with allergic conjunctivitis.

OBJECTIVE

This study compared the clinical efficacy of olopatadine and epinastine in the prevention of itching and conjunctival redness in the conjunctival allergen challenge (CAC) model.

RESEARCH DESIGN AND METHODS

This was a prospective, randomized, double-masked, contralaterally-controlled, single center allergen challenge study. Ninety-six subjects with a history of allergic conjunctivitis were screened, and the 66 who responded to conjunctival allergen challenge at visits 1 and 2 were randomized into 1 of 3 treatment groups at visit 3 to receive one drop of study medication in each eye: (1) olopatadine in one eye and epinastine in the fellow eye, (2) olopatadine in one eye and placebo in the fellow eye, and (3) epinastine in one eye and placebo in the fellow eye. Five minutes after study drop instillation, subjects were bilaterally challenged with the allergen concentration that had elicited a positive conjunctival allergic response at Visits 1 and 2. Subjective itching assessments were given at 3 min, 5 min, and 7 min post challenge. Objective redness and chemosis assessments were made at 10 min, 15 min, and 20 min post challenge. Paired sample two-tailed t-tests were performed on the mean scores at each time point to assess statistical significance in the differences between treatments. MAIN OUTCOME MEASURES;

RESULTS

Fifty-three subjects were randomized into the olopatadine/epinastine treatment group, the primary analysis group. Olopatadine treated eyes exhibited significantly lower mean itching and conjunctival redness scores than the contralateral epinastine treated eyes, -0.19 (p = 0.003) and -0.52 (p < 0.001), respectively. Olopatadine treated eyes also exhibited significantly less chemosis -0.24 (p < 0.001), ciliary redness -0.55 (p < 0.001), and episcleral redness -0.58 (p < 0.001) than epinastine treated eyes.

CONCLUSION

Olopatadine is significantly more effective than epinastine in controlling itching, redness and chemosis associated with allergic conjunctivitis in the CAC model.