Antiallergic action of betotastine besilate (TAU-284) in animal models: A comparison with ketotifen

Comparative study on the efficacy and safety of bepotastine besilate versus levocetirizine in chronic spontaneous urticaria: A randomised, open-label, parallel study

Background Urticaria is a common skin disease which often causes impairment in the quality of life. The ideal drug for chronic urticaria would have antihistaminic and anti-inflammatory actions. Bepotastine besilate is a recently approved novel anti-allergic agent with multiple mechanisms of action; levocetirizine is a potent and selective second-generation H1 receptor antagonist used in the treatment of urticaria. Aim To compare the efficacy and safety of bepotastine besilate versus levocetirizine in patients with chronic spontaneous urticaria. Methods The study design is a randomised, open-label, parallel-group, prospective interventional study. The study subjects were randomly assigned to either of the two groups a and b, each group had 50 patients with chronic urticaria. Statistical analyses were performed using (SPSS, version 18) for all the variables. Chi-square test was used for comparison between categorical variables. An unpaired student's t-test was done for quantitative variables. Results There was a significant decrease in mean urticaria activity score (P < 0.001), chronic urticaria quality of life (P < 0.001) and clinical global improvement (P < 0.001) in both the treatment groups but this improvement was higher in the bepotastine than in the levocetirizine group. There was no significant difference in the mean of absolute eosinophil count, C-reactive protein, aspartate transaminase, alanine transaminase from baseline to 4th week between the two study groups. Visual analogue scale showed statistically significant improvement from baseline to 4th week (P < 0.001) of follow-up but this increase was higher in levocetirizine group (0.64-4.24) than in bepotastine group (0.56-2.56) Limitations Blinding was not done. To assess the efficacy and safety of bepotastine, a larger study can be planned. Conclusion This study found that bepotastine is superior to levocetirizine and showed a statistically significant reduction in mean urticaria activity score 7, improved quality of life and clinical global improvement in patients with urticaria.

The clinical pharmacology of non-sedating antihistamines

We previously reported on brain H₁ receptor occupancy measurements of antihistamines in human brain using [¹¹C]doxepin and positron emission tomography (PET). We proposed the use of brain H₁ receptor occupancy to classify antihistamines objectively into three categories of sedating, less-sedating, and non-sedating antihistamines according to their sedative effects. Non-sedating antihistamines are recommended for the treatment of allergies such as pollinosis and atopic dermatitis because of their low penetration into the central nervous system. Physicians and pharmacists are responsible for fully educating patients about the risks of sedating antihistamines from pharmacological points of view. If a sedating antihistamine must be prescribed, its sedative effects should be thoroughly considered before choosing the drug. Non-sedating antihistamines should be preferentially used whenever possible as most antihistamines are equally efficacious, while adverse effects of sedating antihistamines can be serious. This review summarizes the pharmacological properties of clinically useful non-sedating antihistamines from the perspective of histamine function in the CNS.

Double-blind placebo-controlled study of bepotastine besilate in pediatric patients with perennial allergic rhinitis

BACKGROUND

Although second-generation antihistamines, such as bepotastine besilate, are recommended as a first-line treatment option for adult perennial allergic rhinitis (PAR), few non-sedating second-generation antihistamines are safe for children.

OBJECTIVE

A double-blind, placebo-controlled, comparative study of 473 pediatric PAR patients (7 - 15 years old) to determine the superiority and safety of bepotastine besilate (10 mg twice daily) relative to placebo for improved total and individual nasal symptom scores compared with baseline.

RESEARCH DESIGN AND METHODS

Subjects were randomized to placebo (n = 233) or bepotastine besilate (n = 240, 10 mg orally twice daily for 2 weeks). Interference of daily life by PAR was assessed by measuring change in individual nasal symptom scores from baseline.

RESULTS

Bepotastine besilate was superior to placebo in terms of total nasal symptom scores, with improved overall nasal symptoms of PAR compared with baseline values. Subgroup analyses demonstrated bepotastine besilate was effective irrespective of age, sex or body weight. No clinically significant adverse drug reactions often observed with first-generation antihistamines were reported and no difference in adverse events between groups was observed.

CONCLUSIONS

Bepotastine besilate is effective and safe for pediatric PAR patients aged 7 - 15 years, and has a significant clinical impact on PAR.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01861522 ( https://clinicaltrials.gov/ct2/show/NCT01861522 ).

Treatment of allergic conjunctivitis with bepotastine besilate ophthalmic solution 1.5%

PURPOSE

To examine the pooled per-protocol ocular end points from two conjunctival allergen challenge (CAC) clinical trials of the dual-action antihistamine bepotastine besilate ophthalmic solution (BBOS) 1.5%.

METHODS

Two Phase III, placebo-controlled, double-masked, randomized clinical trials were conducted at a total of six separate centers using the CAC model of allergic conjunctivitis. The same study design was employed for both clinical trials, with subjects randomly assigned to either BBOS 1.5% (n=78) or placebo (n=79) treatment. Each subject received one eye drop of the test agent bilaterally at different study visits 15 minutes, 8 hours, or 16 hours prior to a CAC. Primary ocular end points included changes in ocular itching reported at 3, 5, and 7 minutes and conjunctival hyperemia assessed at 7, 15, and 20 minutes following each CAC. Secondary ocular end points included chemosis as well as episcleral and ciliary hyperemia judged by investigators, and tearing (scored as either absent or present) and eyelid swelling judged by subjects.

RESULTS

A statistically significant reduction in ocular itching was observed for BBOS 1.5% treatment compared to placebo at all time points (P<0.0001), while measures for onset and 8-hour persistence of action also reached clinical significance (ie, ≥1.0 unit difference) at a majority of time points. In addition, a significant reduction in conjunctival hyperemia was achieved at a majority of time points during the onset of action CAC test. Secondary end points were also significantly improved compared to placebo, most prominently for reduced tearing at all study visits and reduced eyelid swelling at the onset of action and 8-hour study visits. Adverse events were generally mild and transient.

CONCLUSION

BBOS 1.5% rapidly reduced CAC-induced ocular itching with duration of effectiveness of at least 8 hours after dosing. Certain secondary signs of inflammation were also significantly reduced.

Comparative efficacy and bioequivalence of novel h1-antihistamine bepotastine salts (nicotinate and salicylate)

Bepotastine salts (nicotinate and salicylate) were investigated for their physicochemical properties to develop novel salt forms of bepotastine, bioequivalent to the bepotastine besilate-loaded tablet (Talion). These bepotastine salts of either nicotinate- or salicylate-loaded tablets were prepared by conventional wet granulation method, and dissolution profiles and pharmacokinetics in beagle dogs were compared to those of Talion. A novel bepotastine nicotinate has a higher solubility at varying pH levels (1.2, 4, or 6.8) than salicylate-loaded or besilate-loaded salt. In addition, those bepostastine salt forms (nicotinate and salicylate) are stable in heat, light, and water. Further, the novel nicotinate- and salicylate-loaded tablets showed similar dissolution rates to Talion in several selected dissolution media and were bioequivalent to Talion in beagle dogs in terms of area under the concentration-time curve (AUC) and maximum observed concentration (Cmax). A pharmacokinetic study performed in beagle dogs demonstrated that test and reference products were found to be bioequivalent in terms of safety, efficacy, and pharmacokinetic properties. These results suggest that bepostastine nicotinate and salicylate formulations are considered applicable candidates and are well tolerated versus the conventional bepostastine besilate formulation.

Bepotastine besilate for the treatment of pruritus

INTRODUCTION

Bepotastine besilate 1.5% is a newly approved second-generation topical antihistamine indicated for the pruritus associated with allergic conjunctivitis. In Japan, the oral formulation is approved to manage pruritus associated with allergic rhinitis and urticaria.

AREAS COVERED

Bepotastine is a piperidine derivative that antagonizes H1 receptors with high selectivity. It has been labeled a dual-acting or multiple-acting antiallergic medication, because it inhibits histamine at H1 receptors and stabilizes mast cells to prevent histamine release. Bepotastine may also have other immunoactive properties, such as inhibition of eosinophil migration, interleukin-5 (IL-5), leukotrienes (e.g., LTB4) and platelet-activating factor (PAF). Human clinical trials demonstrate the efficacy and safety of systemic and ophthalmic bepotastine for pruritus relief, limited penetration across the blood-brain-barrier and kinetics suitable for twice-daily administration.

EXPERT OPINION

Bepotastine besilate 1.5% ophthalmic solution is a safe and effective treatment option for allergic conjunctivitis associated pruritus. Side-effect profile is similar to other ocular antihistamine agents. Additional comparative-effectiveness studies would further advance its clinical use. Oral bepotastine is a safe and effective treatment option approved in Japan for allergic rhinitis, urticaria and pruritus associated with skin diseases.

UPLC-MS/MS method for determination of bepotastine in human plasma

A sensitive and rapid method for quantitation of bepotastine in human plasma has been established using ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). Valsartan was used as an internal standard. Bepotastine and internal standard in plasma sample were extracted using ethylacetate (liquid-liquid extraction). A centrifuged upper layer was then evaporated and reconstituted with the mobile phase of acetonitrile--5 mM ammonium formate (pH 3.5) (85:15, v/v). The reconstituted samples were injected into a phenyl column. Using MS/MS in the multiple reaction monitoring mode, bepotastine and valsartan were detected without severe interference from human plasma matrix. Bepotastine produced a protonated precursor ion ([M+H](+)) at m/z 389 and a corresponding product ion at m/z 167. And the internal standard produced a protonated precursor ion ([M+H](+)) at m/z 436 and a corresponding product ion at m/z 291. Detection of bepotastine in human plasma by the UPLC-ESI-MS/MS method was accurate and precise with a quantitation limit of 0.2 ng/mL. The validation, reproducibility, stability and recovery of the method were evaluated. The method has been successfully applied to pharmacokinetic studies of bepotastine in human plasma.

Oral bepotastine: in allergic disorders

Oral bepotastine is a second-generation histamine H(1) receptor antagonist that also suppresses some allergic inflammatory processes. Numerous short- and long-term clinical trials and surveillance studies have shown that twice-daily bepotastine is an effective and generally well tolerated antihistamine in the treatment of patients with allergic rhinitis, chronic urticaria or pruritus associated with skin conditions (eczema/dermatitis, prurigo or pruritus cutaneus). Bepotastine 20 mg/day was significantly more effective than terfenadine 120 mg/day in patients with perennial allergic rhinitis, as evaluated by the final global improvement rating and several other endpoints in a phase III trial. In phase III trials in patients with chronic urticaria, bepotastine 20 mg/day was more effective than placebo in improving levels of itching and eruption, and as effective as terfenadine 120 mg/day with regard to the final global improvement rating and other endpoints. In a noncomparative trial in patients with pruritus associated with skin diseases, the majority of bepotastine recipients in the overall population, as well as in the specific skin disease subgroups (eczema/dermatitis, prurigo or pruritus cutaneus), had a final global improvement rating of moderate or greater. Bepotastine was generally well tolerated in adult and paediatric patients with allergic conditions.

Non-clinical pharmacology, pharmacokinetics, and safety findings for the antihistamine bepotastine besilate

SCOPE

The purpose of this review is to examine published non-clinical literature on the antihistamine bepotastine besilate, including pharmacokinetic and pharmacologic properties.

METHODS

Standard literature searches using diverse databases were used to find articles on bepotastine besilate published between 1997 and 2009. Articles primarily described non-clinical data utilized for the development of an oral formulation of bepotastine besilate and were published in Japanese. No publications of non-clinical data for an ophthalmic formulation were found in the database searches.

FINDINGS

Bepotastine besilate is a second-generation antihistamine drug possessing selective histamine H(1) receptor antagonist activity. Bepotastine has negligible affinity for receptors associated with undesirable adverse effects, including histamine H(3), α(1)-, α(2)-, and β-adrenergic, serotonin (5-HT(2)), muscarinic, and benzodiazepine receptors. Bepotastine possesses additional anti-allergic activity including stabilization of mast cell function, inhibition of eosinophilic infiltration, inhibition of IL-5 production, and inhibition of LTB(4) and LTD(4) activity. Bepotastine in vivo dose-dependently inhibited the acceleration of histamine-induced vascular permeability and inhibited homologous passive cutaneous anaphylaxis in guinea pig studies. In mouse models of itching, oral bepotastine inhibited the frequency and duration of scratching behavior. Multiple in vivo animal toxicology studies have demonstrated bepotastine to be safe with no significant effects on respiratory, circulatory, central nervous, digestive, or urinary systems. The concentration of bepotastine after intravenous administration of bepotastine besilate (3 mg/kg) in rats was lower in the brain than in plasma, predicting reduced sedation effects compared to older antihistamines.

CONCLUSION

Non-clinical in vitro and in vivo studies have demonstrated bepotastine is a histamine H(1) receptor antagonist with favorable pharmacokinetic, pharmacologic, safety, and antihistamine properties as well as operating on other pathways leading to allergic inflammation beyond those directly involving the histamine H(1) receptor.

Bepotastine besilate ophthalmic solution for the relief of nonocular symptoms provoked by conjunctival allergen challenge

BACKGROUND

Bepotastine besilate is a selective histamine1-receptor antagonist and mast cell stabilizer with inhibitory effects on eosinophilic activity.

OBJECTIVE

To evaluate the safety and efficacy of 1.5% bepotastine besilate ophthalmic solution in alleviating nonocular symptoms induced by a conjunctival allergen challenge (CAC), a clinical model of allergic conjunctivitis.

METHODS

This was a single-center, double-masked, randomized, placebo-controlled clinical trial performed from March 1 to April 4, 2007. Patients 10 years or older with a history of allergic conjunctivitis and a reproducible, positive, clinical response to a CAC were eligible. Patients received either placebo or 1.5% bepotastine besilate, 1 drop in each eye. After 15 minutes, 8 hours, or 16 hours after dosing, a CAC was performed and patients evaluated nonocular symptoms using standardized grading scales.

RESULTS

Seventy-one patients were enrolled in the study, and 66 comprised the per protocol population. A clinically meaningful reduction (> or = 1.0 unit) compared to placebo was achieved for rhinorrhea and nasal congestion at most time points after 1.5% bepotastine besilate instillation at 8 hours before a CAC test. Significant reductions (P < or = .05) in mean values were seen with 1.5% bepotastine besilate at 15 minutes and 8 hours after dosing for CAC-induced nasal congestion, rhinorrhea, ear or palate pruritus, nasal pruritus, and summed nonocular composite symptom (NOCS) scores and also at 16 hours after dosing for nasal congestion and rhinorrhea.

CONCLUSIONS

The 1.5% bepotastine besilate formulation produced statistically significant reductions after a CAC in individual nonocular symptoms and NOCS scores at onset of allergic response and for at least 8 hours after instillation, with the greatest reduction seen for nasal congestion and rhinorrhea.

Bepotastine besilate, a highly selective histamine H(1) receptor antagonist, suppresses vascular hyperpermeability and eosinophil recruitment in in vitro and in vivo experimental allergic conjunctivitis models

To elucidate the ocular pharmacological properties of bepotastine besilate, a selective histamine H(1) receptor antagonist, when compared with other histamine H(1) receptor antagonists, using guinea pig allergic conjunctivitis models and in vitro models of eosinophil recruitment and mast cell membrane stabilization. Conjunctival vascular hyperpermeability was studied in guinea pigs passively sensitized with anti-ovalbumin antiserum or following subconjunctival injection of histamine. Modulation of eosinophil recruitment was evaluated for both platelet-activating factor (PAF)-induced eosinophil infiltration in guinea pigs and leukotriene B(4)-induced in vitro chemotaxis of guinea pig peritoneal eosinophils. Membrane-stabilizing effects of bepotastine also were studied with rat peritoneal mast cells stimulated with the ionophore A23187. Histamine H(1) receptor antagonists including bepotastine besilate were topically administered before ovalbumin, histamine or PAF challenges for in vivo experiments or were added directly to mast cell and eosinophil medium in vitro. Bepotastine besilate significantly inhibited conjunctival vascular hyperpermeability in a dose-dependent manner with maximal effect for bepotastine besilate 1.5%. In separate in vivo experiments, bepotastine besilate 1.0% was significantly more effective than levocabastine 0.025% in the passive sensitization model or olopatadine 0.1% in the histamine-induced hyperpermeability model. Bepotastine besilate 1.0% further suppressed PAF-induced eosinophil infiltration into conjunctival tissue more effectively than ketotifen 0.05%. Chemotaxis of guinea pig peritoneal eosinophils and histamine release from rat peritoneal mast cells in vitro were also inhibited by addition of bepotastine. Olopatadine had a weak effect as compared to that of bepotastine on eosinophil chemotaxis and no effect on mast cell histamine release in our study conditions. Bepotastine besilate was more potent than olopatadine, ketotifen, or levocabastine in reducing vascular hyperpermeability in various animal models of allergic conjunctivitis. Mast cell function and eosinophil chemotaxis were also inhibited in vitro with bepotastine, suggesting bepotastine acts as an inhibitor of allergic response through multiple mechanisms: histamine H(1) receptor antagonism, mast cell stabilization, and inhibition of eosinophil migration to ocular inflammatory sites.

Time to onset and duration of action of the antihistamine bepotastine besilate ophthalmic solutions 1.0% and 1.5% in allergic conjunctivitis: a phase III, single-center, prospective, randomized, double-masked, placebo-controlled, conjunctival allergen challenge assessment in adults and children

BACKGROUND

Bepotastine besilate is a highly selective histamine H(1)-receptor antagonist with antihistaminic, mast cell stabilizing, and anti-inflammatory activity. Based on a history of clinical effectiveness and tolerability of oral bepotastine besilate in the treatment of allergic symptoms, bepotastine besilate is being tested as a potential ophthalmic medication for allergic conjunctivitis.

OBJECTIVE

The aim of this study was to assess the effects of bepotastine besilate ophthalmic solution 1.0% and 1.5% for the treatment of ocular itching and conjunctival hyperemia in a conjunctival allergen challenge (CAC) model in adults and children.

METHODS

This Phase III, single-center, prospective, randomized, double-masked, placebo-controlled, CAC clinical trial enrolled patients >or=10 years of age with a history of allergic conjunctivitis, skin-test reaction, and CAC response. Patients received bepotastine besilate ophthalmic solution 1.0%, bepotastine besilate ophthalmic solution 1.5%, or placebo, 1 drop on each eye on days 14 +/- 3 and 28 +/- 3. The primary efficacy end points, patient-assessed ocular itching (at 3, 5, and 7 minutes) and investigator-assessed conjunctival hyperemia (at 7, 15, and 20 minutes), were determined after CAC according to standardized 5-point scales (0 = none to 4 = severe). Clinical significance was defined in the protocol as >or=1.0-U between-group difference in mean ocular itching scores at the majority of time points at a study visit and also a >or=0.5-U difference at all time points. Tolerability of the test agent was assessed by visual acuity, slit-lamp biomicroscopy, intraocular pressure, dilated funduscopy, and adverse events.

RESULTS

A total of 107 patients (male, 54%; age range, 11-73 years; white race/ethnicity, 93%) received investigational product and comprised the intent-to-treat (ITT) population (bepotastine besilate ophthalmic solution 1.0%, 36 patients; bepotastine besilate ophthalmic solution 1.5%, 35; and placebo, 36). All 107 patients received investigational product at visit 3A (day 0) and were included in the ITT population. Of the 107 patients who were enrolled, 103 completed the study without a protocol deviation or violation. The 1.0% and 1.5% solutions were associated with clinically and statistically significant reductions in mean ocular itching scores compared with placebo on the 15-minute onset-of-action and 8-hour duration-of-action CAC tests (reductions, 1.3-1.5 U and 1.0-1.7 U respectively; all, P < 0.001). Statistically significant reductions in conjunctival hyperemia were achieved with both bepotastine besilate concentrations. Overall, 13 patients experienced a treatment-emergent adverse event considered related to the study drug (bepotastine besilate ophthalmic solution 1.0%, 6 patients; bepotastine besilate ophthalmic solution 1.5%, 4; and placebo, 3).

CONCLUSIONS

In this CAC model of allergic conjunctivitis in adults and children, bepotastine besilate ophthalmic solutions 1.0% and 1.5% were associated with clinically and statistically significant reductions in ocular itching, but not conjunctival hyperemia, within 15 minutes that were maintained for at least 8 hours after administration. Both solutions were well tolerated. ClinicalTrials.gov identifier: NCT00424398.

Leukotriene B(4) mediates sphingosylphosphorylcholine-induced itch-associated responses in mouse skin

In atopic dermatitis, the concentration in the skin of sphingosylphosphorylcholine (SPC), which is produced from sphingomyelin by sphingomyelin deacylase, is increased. In the present study, we investigated the itch-eliciting activity of SPC and related substances and the mechanisms of SPC action in mice. An intradermal injection of SPC, but not sphingomyelin and sphingosine, induced scratching, an itch-associated response, which was not suppressed by a deficiency in mast cells or the H(1) histamine receptor antagonist terfenadine. The action of SPC was inhibited by the mu-opioid receptor antagonist naltrexone. SPC action also was inhibited by the 5-lipoxygenase inhibitor zileuton and the leukotriene B(4) antagonist ONO-4057, but not by the cyclooxygenase inhibitor indomethacin. Moreover, SPC action was inhibited by the antiallergic agent azelastine, which suppresses the action and production of leukotriene B(4). Administration of SPC to the skin and to primary cultures of keratinocytes increased leukotriene B(4) production. SPC increased intracellular Ca(2+) ion concentration in primary cultures of dorsal root ganglion neurons and keratinocytes. These results suggest that SPC induces itching through a direct action on primary afferents and leukotriene B(4) production of keratinocytes. Sphingomyelin deacylase and SPC receptors may be previously unreported targets for antipruritic drugs.

Brain histamine H1 receptor occupancy of orally administered antihistamines, bepotastine and diphenhydramine, measured by PET with 11C-doxepin

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

'Bepotastine besilate' is a novel second-generation antihistamine developed in Japan and its antiallergic effects have already been demonstrated by various studies. However, only a few clinical studies regarding its sedative property are available. In addition, histamine H(1) receptor occupancy (H(1)RO) of this new antihistamine has never been measured by positron emission tomography (PET).

WHAT THIS STUDY ADDS

This paper provides the first measurement result of cerebral H(1)RO of bepotastine besilate (approximately 15%) as determined by PET. This result is in accordance with the clinical classification of bepotastine as a second-generation antihistamine. In addition, the relationship between subjective sleepiness and cerebral H(1)RO of this second-generation antihistamine is demonstrated for the first time using a placebo-controlled crossover study design. AIMS Antihistamines are frequently used for treating various allergic diseases, but often induce sedation. The degree of sedation can be evaluated by measuring histamine H(1) receptor occupancy (H(1)RO) in the brain using positron emission tomography (PET). The aim was to measure H(1)RO of bepotastine, a new second-generation antihistamine, and to compare it with that of diphenhydramine.

METHODS

Eight healthy male volunteers (mean age +/- SD 24.4 +/- 3.3 years) were studied after single oral administration of bepotastine (10 mg), diphenhydramine (30 mg) or placebo, by PET imaging with (11)C-doxepin in a crossover study design. Binding potential ratio and H(1)ROs were calculated using placebo data and were compared between bepotastine and diphenhydramine in the anterior and posterior cingulate gyri (ACG and PCG, respectively), superior and inferior frontal cortices (SFC and IFC, respectively), orbitofrontal cortex (OFC), insular cortex (IC), lateral and medial temporal cortices (LTC and MTC, respectively), parietal cortex (PC), occipital cortex (OC) and sensorimotor cortex (SMC). Plasma concentration of each antihistamine was measured, and its correlation to H(1)RO was examined.

RESULTS

H(1)RO after bepotastine treatment was significantly lower than that after diphenhydramine treatment in all cortical regions (P < 0.001). Mean H(1)ROs of bepotastine and diphenhydramine were 14.7% and 56.4%, respectively. H(1)ROs of both bepotastine and diphenhydramine correlated to their respective drug plasma concentration (P < 0.001).

CONCLUSION

Oral bepotastine (10 mg), with its relatively low H(1)RO and thus minimal sedation, has the potential for use as a mildly or slightly sedative antihistamine in the treatment of various allergic disorders.

Inhibition of histamine-induced bronchospasm in guinea pigs treated with Cecropia glaziovi Sneth and correlation with the in vitro activity in tracheal muscles

A standardized aqueous extract (AE) and a purified fraction (BuF) of Cecropia glaziovi Sneth leaves were tested in unrestrained guinea pigs challenged with histamine. Changes of the respiratory pressure and rate were recorded in a whole body plethysmograph before and after treatment. The concentration of histamine necessary to produce bronchospasm was increased by five-fold following administration of AE (1.0 g/kg p.o.), and by two-fold after treatment with the semi-purified procyanidin/flavonoids enriched BuF (0.1 g/kg p.o.). Both effects were blocked by previous treatment with propranolol (10.0 mg/kg i.p.). In vitro incubation of BuF (0.1-1.0 mg/ml) decreased by 13-55% the maximal response of guinea pig tracheal muscle to histamine, without significant change of EC50. The results confirmed old reports on the useful pulmonary effects of Cecropia extracts. The bronchodilation observed in vivo seems to be related to beta-adrenergic activity observed in vitro only with high concentrations of the purified extract.

Suppression by bepotastine besilate of substance P-induced itch-associated responses through the inhibition of the leukotriene B4 action in mice

Anti-pruritic effects of the antihistamine bepotastine besilate were studied in mice. Bepotastine besilate (10 mg/kg) inhibited scratching induced by an intradermal injection of histamine (100 nmol/site), but not serotonin (100 nmol/site). Bepotastine besilate (1-10 mg/kg, oral) dose-dependently suppressed scratching induced by substance P (100 nmol/site) and leukotriene B(4) (0.03 nmol/site). An intradermal injection of substance P (100 nmol/site) increased the cutaneous concentration of leukotriene B(4), which was not affected by bepotastine besilate (10 mg/kg, oral). Leukotriene B(4) increased Ca(2+) concentration in cultured neutrophils, which was suppressed by bepotastine besilate (1-100 microM). Leukotriene B(4) increased Ca(2+) concentration in cultured dorsal root ganglion neurons, which was also suppressed by bepotastine besilate (100 microM). The results suggest that the inhibition of the actions of leukotriene B(4) as well as histamine is involved in the anti-pruritic effect of bepotastine besilate.

Inhibition of Mast Cell‐Dependent Allergy Reaction by Extract of Black Cohosh (Cimicifuga racemosa)

Black cohosh (Cimicifuga racemosa) has been used as therapeutics for pain and inflammation in Korean folk medicine. The potential effects of black cohosh extract (BCE) on mast cell-dependent allergy reaction, however, have not been well elucidated yet. In the present study, we investigated the effect of BCE on the allergy reaction using mast cell-dependent in vivo and in vitro models. BCE showed no potential of skin sensitization in local lymph node assay (LLNA). The oral administration of BCE significantly inhibited the anti-IgE-induced passive cutaneous anaphylaxis (PCA) reaction. BCE also showed inhibitory potential on the compound 48/80-induced histamine release from rat peritoneal mast cells. In addition, BCE inhibited the IL-4, IL-5 and TNF-alpha mRNA induction by PMA and A23187 in human leukemia mast cells, HMC-1. These results demonstrated that BCE has an anti-allergic potential and it may be due to the inhibition of histamine release and cytokine gene expression in the mast cells.

Effects of bepotastine, cetirizine, fexofenadine, and olopatadine on histamine-induced wheal-and flare-response, sedation, and psychomotor performance

Although many antihistamines are now in clinical use, few studies directly compare their pharmacodynamic and sedative activities in humans in vivo. We designed a double-blind, placebo-controlled, crossover study to compare the inhibitory effects of bepotastine, cetirizine, fexofenadine, and olopatadine on histamine-induced flare-and-wheal response. Systemic sedative effects and impaired psychomotor activities by these drugs were also evaluated. Bepotastine (10 mg twice a day), cetirizine (10 mg once a day), fexofenadine (60 mg twice a day), and olopatadine (5 mg twice a day) or placebo was given in a double-blind manner to seven healthy volunteers before histamine challenge by iontophoresis. At 0, 1, 2, 4, 8, 12, and 24 h following the oral administration of these drugs, histamine iontophoresis-induced wheal-and-flare response was measured. Sedative effects by the drugs were also evaluated by a visual analogue scale for subjective sedation, and by word processor test for psychomotor activity. Each volunteer was tested with all of the drugs (including placebo), administered in a random order with a washout period of at least 1 week. Histamine iontophoresis induced marked wheal-and-flare response in all participants. Bepotastine, cetirizine, fexofenadine, and olopatadine yielded significant reduction of histamine-induced wheal-and-flare response compared to placebo (P < 0.01). Among the drugs, olopatadine and cetirizine suppressed most markedly and persistently histamine-induced wheal-and-flare response, while bepotastine and fexofenadine produced a significant, but less persistent suppression. Olopatadine, fexofenadine, and cetirizine showed a significant systemic sedative effect in this order with bepotastine showing the least sedative effect. Moreover, olopatadine affected psychomotor performance most markedly, which was followed by fexofenadine and cetirizine. These results indicate that bepotastine, cetirizine, fexofenadine, and olopatadine inhibit histamine-induced wheal-and-flare response of humans in vivo and induce a variable systemic sedative effect and impaired psychomotor activity. Although olopatadine and cetirizine showed the strongest and most persistent suppression of histamine-induced wheal-and-flare response, olopatadine showed a considerable sedative effect with impaired psychomotor performance.

Role of mast cells in antigen-induced airway inflammation and bronchial hyperresponsiveness in rats

The participation of mast cells in the induction of antigen-induced airway inflammation and bronchial hyperresponsiveness (BHR) to acetylcholine (ACh) was investigated using pharmacological agents and mast cell-deficient rats (Ws/Ws). A significant increase in the number of leukocytes in bronchoalveolar lavage fluid (BALF) and bronchial responsiveness to ACh were observed 24 h after antigen (ovalbumin) challenge in sensitized Brown-Norway (BN) rats. Disodium cromoglycate and terfenadine did not inhibit antigen-induced airway inflammation and BHR in sensitized BN rats. In contrast, cyclosporin A (CyA), FK-506 and prednisolone significantly inhibited antigen-induced airway inflammation and BHR in sensitized BN rats. In addition, disodium cromoglycate, terfenadine and prednisolone, but not CyA and FK-506, inhibited homologous passive cutaneous anaphylaxis in rats. Furthermore, a significant increase in the number of leukocytes in BALF and BHR was also observed in Ws/Ws rats 24 h after inhalation of antigen; however, the magnitude of BHR in Ws/Ws rats was lower than that in the congenic rats. These findings suggest that mast cells play a partial role in the development of antigen-induced BHR in rats and that the induction of BHR is barely suppressed by mast cell stabilizing agents.