olopatadine-hydrochloride and isospaglumic-acid

In order to compare the relative efficacy of topical antihistamines with balanced saline solution (BSS) and benzalkonium chloride (BC) in the early phase of allergic conjunctivitis in an animal model of ocular anaphylaxis, 96 male guinea pigs were sensitized with intraperitoneal egg albumin (EA) and aluminum hydroxide. Seventy-six animals were used for determination of Evans blue (EB) extravasation and 20 for clinical evaluation of the allergic response (redness, edema, discharge and itch-scratch response). Eighteen days after sensitization the animals were topically challenged by conjunctival instillation of EA and treated 15 min before and 15 min after challenge with commercially available drugs (ketotifen, ketotifen single dose units [SDU], olopatadine, azelastine, spaglumic acid and emedastine) and controls (BSS and BC). The animals used for EB quantification were anesthetized and received an intravenous injection of EB simultaneously to the topical challenge. The ocular extravasation of the colorant was determined by 620 nm absorbance spectrophotometry. The animals used for clinical evaluation were observed for clinical signs of the allergic reaction. EB ocular extravasation was significantly lower in the eyes treated by spaglumic acid and emedastine. The clinical scoring was consistent with EB extravasation, though the difference was not statistically significant. Spaglumic acid and emedastine seem to be the most useful drugs to reduce EB extravasation and allergic signs in an animal model of early phase allergic conjunctivitis.

Topics: Animals; Anti-Allergic Agents; Benzimidazoles; Coloring Agents; Conjunctivitis, Allergic; Dibenzoxepins; Dipeptides; Disease Models, Animal; Drug Evaluation, Preclinical; Evans Blue; Guinea Pigs; Histamine H1 Antagonists; Ketotifen; Male; Olopatadine Hydrochloride; Ophthalmic Solutions; Phthalazines; Severity of Illness Index; Treatment Outcome

Recent decades have been marked by an increasing number of patients suffering from ocular allergic-like symptoms without being associated with an increase in IgE levels. These symptoms include heaviness of the lid, foreign body sensation, burning, stinging and photophobia. Both epidemiological studies and controlled human exposure clinical studies have shown cause-effect relationships between allergic-like symptoms and environmental factors such as outdoor air pollutants or poor indoor air quality. An ocular surface subclinical inflammation is thought to be responsible for pseudoallergic, pollution-related conjunctivitis. The complement system is considered as one of the major effector mechanisms involved in initiation of the subclinical inflammation that leads to IgE-independent eye irritation.. To study the capability of nine antiallergic eyedrops commonly used in the treatment of allergic conjunctivitis to inhibit complement activation induced in vitro by pollutants.. Normal human serum obtained from healthy individuals was used as a source of complement. Activation of complement was assessed using the complement hemolytic 50% (CH50) assay, in the absence or the presence of antiallergic eyedrops and in the absence or the presence of various stimuli, including sand, common house dust, eye mascara, and Dactylis glomerata pollen extract. Zymosan was used as a standardized complement activator. The following eyedrops were studied: Naabak (4.9% N-acetyl aspartic acid-glutamic acid, NAAGA, sodium salt), Almide (lodoxamide 0.1%), Levophta (0.05% levocabastine), Emadine (0.05% emedastine), Tilavist (2% nedocromil), Allergodil (0.05% azelastine), Patanol (olopatadine), and Zaditen (0.025% ketotifen). Effects of preservative-free lodoxamide and ketotifen were also assessed and compared to those of the preserved formulations. A solution of 0.01% benzalkonium chloride (BAC), the most widely used preservative in topical eyedrops, was also tested.. Zymosan-induced activation of complement (30+/-6%) was significantly lowered by preincubation of serum with unpreserved NAAGA (16.6+/-4%, p=0.0026) or benzalkonium-preserved nedocromil (20+/-2%, p=0.022). Preserved levocabastine, emedastine, olopatadine and ketotifen did not interfere with zymosan-induced complement activation, whereas preserved azelastine, lodoxamide and benzalkonium chloride significantly aggravated complement activation induced by zymosan. Similar results were obtained when complement activation was triggered by sand, common house dust, mascara, or by an allergenic extract of Dactylis glomerata pollen. In the absence of complement activator, none of the antiallergic eyedrops induced a significant change in CH50 titer, indicating that the deleterious pro-inflammatory effect of preserved azelastine and lodoxamide may occur only once complement activation has been initiated, i.e., on an inflamed ocular surface.. Among the antiallergic eyedrops tested in this study, only Naabak and Tilavist were found to significantly inhibit complement activation triggered by particulate matters or pollen allergenic extract. Such an anticomplement activity confers these two molecules a potential in the therapeutic management of pollution-related pseudoallergic conjunctivitis.

Topics: Air Pollutants; Anti-Allergic Agents; Benzalkonium Compounds; Benzimidazoles; Complement Activation; Conjunctivitis; Cosmetics; Dibenzoxepins; Dipeptides; Drug Evaluation; Dust; Humans; In Vitro Techniques; Ketotifen; Nedocromil; Olopatadine Hydrochloride; Ophthalmic Solutions; Oxamic Acid; Phthalazines; Piperidines; Pollen; Silicon Dioxide; Zymosan