Inhibitory effects of azelastine on nasal allergic responses in sensitized guinea pigs

The effect of antiallergic intranasal formulations on ciliary beat frequency of human nasal epithelium in vitro

The nasal mucociliary clearance is an important defense mechanism of the upper respiratory tract. It is known to be influenced by many pharmacologic substances. We investigated the effects of three topical intranasal antiallergic formulations containing disodium cromoglycate (DNCG), dimethindene maleate (DMM), and azelastine-HCL (AZL) on nasal ciliary beat frequency (CBF) in vitro. Nasal ciliated cells were harvested from 16 healthy volunteers. Cells were diluted 1:10 in culture medium and incubated with a placebo formulation (PLAC), containing 0.022% benzalkonium chloride, which was part of all formulations, a registered 2% formulation of DNCG, a 0.1% formulation of DMM, and a registered 0.1% formulation of AZL. After an incubation period of 20 min, CBF was registered by a photoelectric measurement device. Under control conditions (CONTROL), CBF was 11.4 +/- 1.3 Hz. PLAC reduced CBF to 9.7 +/- 2.3 Hz (NS). DNCG reduced CBF to 9.7 +/- 2 Hz (NS). DMM reduced CBF to 7.2 +/- 1.7 Hz (P < or = 0.05 vs CONTROL, NS vs PLAC), and AZL reduced CBF to 0.9 +/- 1.8 Hz (P < or = 0.001 vs CONTROL, P < or = 0.001 vs DNCG, P < or = 0.001 vs PLAC). In conclusion, a possible influence of antiallergic intranasal formulations on nasal ciliary function has to be considered in clinical application.

Inhibition of leukotriene synthesis by azelastine

BACKGROUND

Azelastine, oxatomide, and ketotifen are used for patients with allergic diseases. These drugs inhibit the release of chemical mediators including the leukotrienes; however, the mechanism involved is unclear.

OBJECTIVE

To clarify the mechanism of inhibition, we investigated the effects of three drugs on the function of phospholipase A2, 5-lipoxygenase, leukotriene C4 synthase, and leukotriene A4 hydrolase, which are all catabolic enzymes involved in synthesizing leukotriene C4 and leukotriene B4 in rat basophilic leukemia (RBL)-1 cells.

METHODS AND RESULTS

The production of leukotriene C4 and leukotriene B4 was measured by high performance liquid chromatography (HPLC). All three drugs inhibited the production of leukotriene C4 and leukotriene B4 when cells were stimulated with A23187. All three drugs also inhibited the A23187-stimulated release of 3H-arachidonic acid from membrane phospholipids. Azelastine inhibited the production of leukotriene C4, but not leukotriene B4, when either arachidonic acid or leukotriene A4 free acid was used as the substrate in our cell free system. Oxatomide and ketotifen did not inhibit the synthesis of either leukotriene C4 or leukotriene B4 in the same cell free study.

CONCLUSION

Results indicated that oxatomide and ketotifen inhibit the production of leukotriene C4 and leukotriene B4 by inhibiting phospholipase A2 activity, whereas, azelastine inhibits the leukotriene C4 production by inhibiting phospholipase A2 and leukotriene C4 synthase.

Safety and efficacy of azelastine nasal spray (Astelin NS) for seasonal allergic rhinitis: a 4-week comparative multicenter trial

BACKGROUND

Azelastine is a chemically novel investigational antiallergy drug with the ability to antagonize the effects of chemical mediators of the early- phase and late phase allergic responses suggesting its usefulness in the treatment of upper and lower airway diseases.

OBJECTIVE

The objective of this 4-week, double- bind, multicenter trial was to evaluate the efficacy of azelastine nasal spray in subjects with seasonal allergic rhinitis.

METHODS

Two hundred sixty-four subjects 12 years of age and older were randomized to receive either azelastine, 2 sprays/nostril qd; azelastine, 2 sprays/nostril bid; oral chlorpheniramine maleate, 12 mg bid; or placebo. The primary efficacy parameters were the changes in major and total symptom severity scores.

RESULTS

Overall, across all 4 weeks of treatment, the mean percent improvements in the total and major symptom complex severity scores in both azelastine treatment groups were greater than those for the placebo group. For the azelastine 2 sprays bid group, the overall results were significant at P = .05 for the major symptom complex score and at .05 < P = .10 for the total symptom complex score versus placebo. For both azelastine treatment groups, improvements in all of the individual rhinitis symptoms were superior to those for the placebo group and, in general were clinically and statistically significant. Azelastine nasal spray was well tolerated; adverse experiences were generally application site reactions, mild to moderate, and not limiting to continued treatment.

CONCLUSIONS

Azelastine nasal spray demonstrated broad clinical antirhinitis activity that for the 2 sprays/nostril bid dosage regimen was consistently clinically and statistically significant.

Azelastine--a novel in vivo inhibitor of leukotriene biosynthesis: a possible mechanism of action: a mini review

Leukotrienes have been proposed as important chemical mediators of allergic inflammation, and there is evidence that azelastine (Astelin) can affect leukotriene-mediated allergic responses. One of the enzymes required for the synthesis of leukotrienes from arachidonic acid is 5-lipoxygenase (5-LO). Azelastine, which is preferentially taken up by the lung and alveolar macrophages, inhibits leukotriene generation in the airways. This property of azelastine may contribute to its therapeutic efficacy in the long-term treatment and management of rhinitis and asthma. Azelastine does not directly inhibit 5-LO in disrupted murine peritoneal cells and rat basophilic leukemia cells (IC50 > 100 microM), but does have moderate 5-LO inhibitory activity in intact murine peritoneal cells (IC50 = 10 microM, 5 min) and in chopped guinea pig liver (IC50 = 14 microM, 2 hr). The generation and release of leukotrienes in human neutrophils and eosinophils is also inhibited by azelastine (IC50 = 0.9-1.1 microM). Furthermore, azelastine is a potent and specific inhibitor of allergen-induced generation of leukotrienes in the nose of the guinea pig (ID50 < 100 micrograms/kg, im, 20 min) as well as in patients with rhinitis (2 mg, po, 4 hr; ID50 < 30 micrograms/kg). Azelastine also inhibits allergen-induced, leukotriene-mediated, pyrilamine-resistant bronchoconstriction (oral ID50 = 60 micrograms/kg, 2 hr and 120 micrograms/kg, 24 hr). This profile suggests that azelastine may be a novel inhibitor of Ca(2+)-dependent translocation of 5-lipoxygenase from cytosol to the nuclear envelope or a FLAP inhibitor rather than a direct 5-LO inhibitor.