Comparison of cytotoxicities and anti-allergic effects of topical ocular dual-action anti-allergic agents.

BACKGROUND: To investigate the cytotoxicities of the topical ocular dual-action anti-allergic agents (alcaftadine 0.25%, bepotastine besilate 1.5%, and olopatadine HCL 0.1%) on human corneal epithelial cells (HCECs) and their anti-allergic effects on cultured conjunctival epithelial cells. METHODS: A Methylthiazolyltetrazolium(MTT)-based calorimetric assay was used to assess cytotoxicities using HCECs at concentrations of 10, 20 or 30% for exposure durations of 30 min, 1 h, 2 h, 12 h or 24 h. Cellular morphologies were evaluated by inverted phase-contrast and electron microscopy. Wound widths were measured 2 h, 18 h, or 24 h after confluent HCECs monolayers were scratched. Realtime PCR was used to quantify anti-allergic effects on cultured human conjunctival cells, in which allergic reactions were induced by treating them with Aspergillus antigen. RESULTS: Cell viabilities decreased in time- and concentration-dependent manners. Cells were detached from dishes and showed microvilli loss, cytoplasmic vacuoles, and nuclear condensation when exposed to antiallergic agents; alcaftadine was found to be least cytotoxic. Alcaftadine treated HCECs monolayers showed the best wound healing followed by bepotastine and olopatadine (p < 0.0001). All agents significantly reduced the gene expressions of allergic cytokines (IL-5, IL-25, eotaxin, thymus and activation-regulated chemokine, and thymic stromal lymphopoietin) and alcaftadine had the greatest effect (p < 0.0001 in all cases). CONCLUSIONS: Alcaftadine seems to have less side effects and better therapeutic effects than the other two anti-allergic agents tested. It may be more beneficial to use less toxic agents for patients with ocular surface risk factors or presumed symptoms of toxicity.

Study of the anti-allergic and anti-inflammatory activity of Brachychiton rupestris and Brachychiton discolor leaves (Malvaceae) using in vitro models.

BACKGROUND: Brachychiton rupestris and Brachychiton discolor (Malvaceae) are ornamental trees native to Australia. Some members of Brachychiton and its highly related genus, Sterculia, are employed in traditional medicine for itching, dermatitis and other skin diseases. However, scientific studies on these two genera are scarce. Aiming to reveal the scientific basis of the folk medicinal use of these plants, the cytotoxicity, anti-inflammatory and anti-allergic activities of Brachychiton rupestris and Brachychiton discolor leaves extracts and fractions were evaluated. Also, phytochemical investigation of B. rupestris was performed to identify the compounds exerting the biological effect. METHODS: Extracts as well as fractions of Brachychiton rupestris and Brachychiton discolor were tested for their cytotoxicity versus hepatoma HepG2, lung A549, and breast MDA-MB-231 cancer cell lines. Assessment of the anti-allergic activity was done using degranulation assay in RBL-2H3 mast cells. Anti-inflammatory effect was tested by measuring the suppression of superoxide anion production as well as elastase release in fMLF/CB-induced human neutrophils. Phytochemical investigation of the n-hexane, dichloromethane and ethyl acetate fractions of B. rupestris was done using different chromatographic and spectroscopic techniques. RESULTS: The tested samples showed no cytotoxicity towards the tested cell lines. The nonpolar fractions of both B. rupestris and B. discolor showed potent anti-allergic potency by inhibiting the release of ß-hexosaminidase. The dichloromethane fraction of both species exhibited the highest anti-inflammatory activity by suppressing superoxide anion generation and elastase release with IC50 values of 2.99 and 1.98 µg/mL, respectively for B. rupestris, and 0.78 and 1.57 µg/mL, respectively for B. discolor. Phytochemical investigation of various fractions of B. rupestris resulted in the isolation of ß-amyrin acetate (1), ß-sitosterol (2) and stigmasterol (3) from the n-hexane fraction. Scopoletin (4) and ß-sitosterol-3-O-ß-D-glucoside (5) were obtained from the dichloromethane fraction. Dihydrodehydrodiconiferyl alcohol 4-O-ß-D-glucoside (6) and dihydrodehydrodiconiferyl alcohol 9-O-ß-D-glucoside (7) were separated from the ethyl acetate fraction. Scopoletin (4) showed anti-allergic and anti-inflammatory activity. CONCLUSIONS: It was concluded that the nonpolar fractions of both Brachychiton species exhibited anti-allergic and anti-inflammatory activities.

Analysis of Toxicity Effects of Buspirone, Cetirizine and Olanzapine on Human Blood Lymphocytes: in Vitro Model.

BACKGROUND: The current study investigates the cytotoxicity mechanism of common drugs with piperazine ring such as cetirizine, olanzapine and buspirone on human lymphocytes. METHODS: The viability of lymphocytes, reactive oxygen species (ROS) formation, mitochondrial membrane potential (MMP) collapse, lysosomal integrity, content of glutathione and lipid peroxidation was determined. RESULTS: Buspirone and cetirizine showed more toxicity than olanzapine on human lymphocytes with an IC50 value of 200 µg/ml, after 6 h of incubation. Significant ROS formation, MMP collapse, lipid peroxidation, lysosomal damage and elevation of glutathione disulfide (GSSG) were observed in treated lymphocytes concentrations (4, 20, 40 µg/ml) of buspirone and cetirizine. CONCLUSION: Our results show the exposure of human lymphocytes with buspirone and cetirizine, which usually happens during the poisoning, triggers oxidative stress and organelle damages. Our study suggests that using antioxidants, mitochondrial and lysosomal protective agents can protect blood lymphocytes, from probable side effects of these highly consumed medications.

Antiallergic and antihistaminic actions of Ceasalpinia bonducella seeds: Possible role in treatment of asthma.

ETHNOPHARMACOLOGICAL RELEVANCE: Seed kernel of the plant Ceasalpinia bonducella Linn (Caesalpiniacaeae) are used for the treatment of asthma in folk medicine and ancient books. AIM OF STUDY: To assess the pharmacological efficacy of the plant in asthma and to confine and describe the synthetic constituents from the seeds that are in charge of the action. MATERIAL AND METHODS: The viability of petroleum ether, ethanol extract and ethyl acetate fraction from ethanol extract of C. bonducella seeds were screened for the treatment of asthma by various methods viz. effect of test drug on clonidine and haloperidol induced catalepsy, milk-induced leukocytosis and eosinophilia, mast cell stabilizing activity in mice and studies on smooth muscle preparation of guinea pig ileum (in-vitro). Column chromatography of active extract was done to pinpoint the active compound followed by structure elucidation by FTIR, GCMS and NMR spectroscopic methods. RESULTS: Ethyl acetate fraction from ethanol extract of C. bonducella seeds exhibited antihistaminic activity at the dose of 50 and 100 mg/kg, inhibited clonidine-induced catalepsy but not haloperidol-induced catalepsy. Ethyl acetate fraction from ethanol extract significantly inhibited increased leukocyte and eosinophil count due to milk allergen and showed maximum protection against mast cell degranulation by clonidine. The results of guinea pig ileum indicated that the compound 2 methyl, 1 hexadecanol isolated from ethyl acetate fraction of ethanol extract relaxed significantly the ileum muscle strips pre-contracted by which suggests the involvement of ß2-agonists on the relaxation of the tissue. All the results are dose dependent. Active ethyl acetate fraction from ethanol extract showed presence of anti-asthmatic compound, 2-methyl, 1-hexadecanol. CONCLUSION: The ethyl acetate fraction from ethanol extract of seeds of the plant C. bonducella can inhibit parameters linked to asthma disease.

Ecotoxicity of the antihistaminic drug cetirizine to Ruditapes philippinarum clams.

Cetirizine (CTZ) is an antihistaminic drug present in the aquatic environment, with limited information on its toxicity to organisms inhabiting this system. This study intended to evaluate the effects of CTZ on oxidative stress and energy metabolism biomarkers in the edible clam Ruditapes philippinarum after a 28days exposure to environmentally relevant CTZ concentrations (0.0, 0.3, 3.0, 6.0 and 12.0µg/L). The results obtained showed that CTZ was accumulated by clams reaching maximum concentrations (up to ~22ng/g FW) at the highest CTZ exposure concentrations (6.0 and 12.0µg/L). The bioconcentration factor (average maximum values of ~5) decreased at 12.0µg/L reflecting a reduction in clams uptake or increase of excretion capacity at this condition. The present study revealed that, in general, clams decreased the metabolic potential after exposure to CTZ (decrease in electron transport system activity), a response that led to the maintenance of glycogen content in organisms exposed to CTZ in comparison to control values. Our findings also showed that, CTZ did not exert significant levels of oxidative injury to clams. However, comparing the control with the highest exposure concentrations (6.0 and 12.0µg/L) a significant increase of the antioxidant enzyme superoxide activity (~53 and ~44%) was observed in clams exposed to CTZ. Moreover, a tendency to increase lipid peroxidation (~14 and ~9%) and carbonyl groups on proteins (~11 and ~3%) was observed in clams exposed to CTZ (6.0 and 12.0µg/L) compared to control condition. Overall the present study suggests that toxic impacts may be induced in R. philippinarum if exposed for longer periods or higher CTZ concentrations.

Strategic application of self-micellizing solid dispersion technology to respirable powder formulation of tranilast for improved therapeutic potential.

PURPOSE: The present study aimed to develop an inhalable self-micellizing solid dispersion of tranilast (SMSD/TL) using poly[MPC-co-BMA] to improve the therapeutic potential and safety. METHODS: The safety of poly[MPC-co-BMA] in lungs was assessed using rat lung epithelium-derived L2 cells. SMSD/TL and respirable powder of SMSD/TL (SMSD/TL-RP) were prepared using a wet milling system and jet mill, respectively. The physicochemical properties of TL formulations were characterized in terms of dissolution, morphology, and particle size. Pharmacological and pharmacokinetic studies were also conducted on inhaled SMSD/TL-RP. RESULTS: The lactate dehydrogenase level from L2 cells treated with poly[MPC-co-BMA] was lower than that with polysorbate 80, a positive control. SMSD/TL showed enhanced dissolution behavior of TL. The jet milled SMSD/TL particles easily separated from the lactose carrier, and the particle size was suitable for inhalation. Compared with RP of TL, inhaled SMSD/TL-RP (100 µg-TL/rat) could more strongly suppress the inflammatory responses in antigen-sensitized rats. The TL level in plasma after intratracheal administration of SMSD/TL-RP at a pharmacological effective dose (100 µg-TL/rat) was ca. 4.2-fold lower than that after oral administration of TL solution at a clinical dose (1.67 mg/kg). CONCLUSION: SMSD/TL-RP might be an attractive dosage form to improve the anti-inflammatory effects and safety of TL.

In vitro effects of preserved and unpreserved anti-allergic drugs on human corneal epithelial cells.

PURPOSE: Treatment with topical eye drops for long-standing ocular diseases like allergy can induce detrimental side effects. The purpose of this study was to investigate in vitro cytotoxicity of commercially preserved and unpreserved anti-allergic eye drops on the viability and barrier function of monolayer and stratified human corneal-limbal epithelial cells. METHODS: Cells were treated with unpreserved ketotifen solution, benzalkonium chloride (BAC)-containing anti-allergic drugs (ketotifen, olopatadine, levocabastine) as well as BAC alone. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to determine cell viability. Effects of compounds on barrier function were analyzed measuring transepithelial electrical resistance (TEER) to determine paracellular permeability and rose bengal assays to evaluate transcellular barrier formation. RESULTS: The BAC-preserved anti-allergic formulations and BAC alone significantly reduced cell viability, monolayer cultures being more sensitive to damage by these solutions. Unpreserved ketotifen induced the least diminution in cell viability. The extent of decrease of cell viability was clearly dependent of BAC presence, but it was also affected by the different types of drugs when the concentration of BAC was low and the short time of exposure. Treatment with BAC-containing anti-allergic drugs and BAC alone resulted in increased paracellular permeability and loss of transcellular barrier function as indicated by TEER measurement and rose bengal assays. CONCLUSIONS: The presence of the preservative BAC in anti-allergic eye drop formulations contributes importantly to the cytotoxic effects induced by these compounds. Stratified cell cultures seem to be a more relevant model for toxicity evaluation induced on the ocular surface epithelia than monolayer cultures.

Topically applied ZnO nanoparticles suppress allergen induced skin inflammation but induce vigorous IgE production in the atopic dermatitis mouse model.

BACKGROUND: Metal oxide nanoparticles such as ZnO are used in sunscreens as they improve their optical properties against the UV-light that causes dermal damage and skin cancer. However, the hazardous properties of the particles used as UV-filters in the sunscreens and applied to the skin have remained uncharacterized. METHODS: Here we investigated whether different sized ZnO particles would be able to penetrate injured skin and injured allergic skin in the mouse atopic dermatitis model after repeated topical application of ZnO particles. Nano-sized ZnO (nZnO) and bulk-sized ZnO (bZnO) were applied to mechanically damaged mouse skin with or without allergen/superantigen sensitization. Allergen/superantigen sensitization evokes local inflammation and allergy in the skin and is used as a disease model of atopic dermatitis (AD). RESULTS: Our results demonstrate that only nZnO is able to reach into the deep layers of the allergic skin whereas bZnO stays in the upper layers of both damaged and allergic skin. In addition, both types of particles diminish the local skin inflammation induced in the mouse model of AD; however, nZnO has a higher potential to suppress the local effects. In addition, especially nZnO induces systemic production of IgE antibodies, evidence of allergy promoting adjuvant properties for topically applied nZnO. CONCLUSIONS: These results provide new hazard characterization data about the metal oxide nanoparticles commonly used in cosmetic products and provide new insights into the dermal exposure and hazard assessment of these materials in injured skin.

Oral toxicity evaluation of kefir-isolated Lactobacillus kefiranofaciens M1 in Sprague-Dawley rats.

Lactobacilli kefiranofaciens M1 has shown novel immunomodulation and anti-allergy probiotic attributes in cell and animal models. An acute oral toxicity assessment of L. kefiranofaciens M1 was evaluated in Sprague-Dawley rats. The rats were randomly assigned to four groups (12 rats/sex/group): the low dose group was orally gavaged with L. kefiranofaciens M1 at 3.0×10(8)cfu/kg bw while the medium dose and high dose groups received 9.0×10(9)cfu/kg bw and 1.8×10(10)cfu/kg bw, respectively, for 28days. The control group received phosphate buffer saline. The body weights were measured weekly while blood samples were collected for haematology and serum biochemistry tests. Histopathology of the organs (heart, liver, kidney, adrenal glands, spleen, ovary, testis), and urinalysis were conducted on study termination. The body weight gain of the L. kefiranofaciens M1 and control groups were comparable during the administration period. Overall, L. kefiranofaciens M1 did not induce adverse effects on haematology, serum biochemistry, and urinalysis parameters. Gross and microscopic histopathology of the organs revealed no toxicity effect of L. kefiranofaciens M1. In conclusion, 1.8×10(10)cfu/kg bw of L. kefiranofaciens M1 was considered as the no-observed-adverse-effect-level (NOAEL), which was the highest dose tested in the present study.

High-dose tranilast administration to rats creates interstitial cystitis-like symptoms with increased vascular permeability.

AIM: We investigated whether the high-dose administration of tranilast could be used to create an animal model of interstitial cystitis (IC). Then, we used this model to assess the relationship between IC and changes in the vascular permeability of the bladder. MAIN METHODS: Female rats were divided into the following 4 groups: a control group, a tranilast group, a carbazochrome group and a combination (tranilast+carbazochrome) group. Continuous cystometry, bladder distension, and the Evans blue dye extravasation test were performed 4weeks after drug administration. Locomotor activity, the plasma TGF-ß1 level, and collagen fibers in the bladder wall were also examined in the control and tranilast groups. KEY FINDINGS: The interval between bladder contractions was shorter and the leakage of Evans blue dye into the bladder wall was greater in the tranilast group than in the control group. Glomerulations of the bladder wall after bladder distention and thinning of the collagen fiber layer in the bladder were observed in the tranilast group. Locomotor activity in darkness and the plasma TGF-ß1 level were both lower in the tranilast group than in the control group. In the combination group, the leakage of Evans blue dye was greater than in the control group; however, it was less prominent than in the tranilast group. SIGNIFICANCE: These results suggest that high-dose administration of tranilast to rats can create an IC-like rat model and that an increase in the vascular permeability of the bladder wall may be one cause of IC symptoms.

A new antiallergic agent that binds to dimerized translationally controlled tumor protein and inhibits allergic symptoms is nontoxic.

Dimerized translationally controlled tumor protein (dTCTP) plays a role in allergic diseases. A 7-mer peptide, dimerized translationally binding protein 2 (dTBP2), binds to dTCTP and inhibits dTCTP, suggesting that the 7-mer peptide may have therapeutic potential. We assessed the safety of dTBP2 by examining its cytotoxicity to both human bronchial epithelial cells and mice. dTBP2 did not cause cytotoxicity to the epithelial cells in concentrations up to 100 µg/ml. Also, dTBP2 caused no adverse effects upon repeated administration of 50 mg/kg over 24 h to mice. Hence, we conclude that dTBP2 is a safe candidate drug for use in the therapy of allergic diseases.

Anti-stress and anti-allergic effect of Actiniopteris radiata in some aspects of asthma.

Successive extracts of whole plant of Actiniopteris radiata screened for its therapeutic potential as an antiallergic and antistress agent in asthma using specific in vivo animal models. Only ethanol extract (AREE) at a higher dose of 100 mg/kg i.p significantly (p < 0.05) decreased milk induced eosinophilia by 16.20 ± 2.235 when compared with control group while even lower doses of 50 mg/kg, i.p exhibited significant inhibition (P < 0.05) of leukocytosis induced by milk in mice. Other extracts like petroleum ether, ethyl acetate and methanol unable to exhibit that significant potential. Results obtained thus validate the traditional claim of the Actiniopteris radiata utilization in different aspect of asthma due to presence of various polar secondary metabolites in ethanol extract.

Chronic toxicity of diphenhydramine hydrochloride to a freshwater mussel, Lampsilis siliquoidea, in a flow-through, continuous exposure test system.

Freshwater mussel populations are declining in North America. Potential anthropogenic stressors may be contributing to the declines and may include the continual presence of pharmaceutical compounds in waterways. Diphenhydramine hydrochloride (DH) is an over-the-counter antihistamine marketed under several name brand products including the common U.S. trademarked product, Benadryl™. The toxicity of DH to freshwater mussels was assessed by initiating an unprecedented 28 day, continuous exposure trial with 1 day old mussels. Results indicated that the survival and growth of Lampsilis siliquoidea was not impacted by DH concentrations ≤121 µg/L after 28 days of continuous exposure. With the successful completion of this study, the techniques are now verified to evaluate the toxicity of waterborne compounds initiating 28-day chronic exposures with 1 day old mussels.

Evaluation of antiallergic and anti-anaphylactic activity of ethanolic extract of Sanseveiria trifasciata leaves (EEST) in rodents.

AIM OF THE STUDY: The leaves and rhizomes of Sansevieria trifasciata are used in folk medicine for treating bronchitis, asthma, cough, snake bite and insect bite etc. The ethanolic extract elicited analgesic, anti-inflammatory and antipyretic activity. Hence, it was decided to study the antiallergic activity of ethanolic extract of S. trifasciata (EEST) on various animal models as well as in vitro conditions, and also to understand possible mechanism of action. MATERIALS AND METHODS: Ethanolic extract of S. trifasciata leaves (EEST) were prepared by cold maceration followed by concentration and evaporation under reduced pressure on a rotary evaporator to obtain semisolid mass. The various phytoconstituents were analyzed. The acute toxicity study of EEST was carried out in mice. The antiallergic and anaphylactic activities were evaluated using animal models viz. milk induced eosinophilia and leukocytosis, compound 48/80 induced mast cell degranulation, active and passive cutaneous anaphylaxis and histamine induced pedal edema. In addition, EEST effect on Shultz-Dale reaction in sensitized guinea pig ileum in ex vivo and antioxidant activity by free radical scavenging by DPPH method (in vitro) were also studied. RESULTS: EEST treatment at 100mg/kg and 200mg/kg p.o inhibited (a) milk-induced increased eosinophilia, leukocytosis, monocytes and neutrophils. (b) Prevented passive cutaneous and active anaphylactoid reactions. (c) Prevented compound 48/80 induced degranulation of sensitized mesenteric mast cells. (d) Inhibited histamine induced pedal edema formation significantly. EEST pretreatment inhibited Shultz-Dale reaction in guinea pig ileum and also elicited potent antioxidant activity. CONCLUSION: Experimental findings demonstrate promising antiallergic and anti-anaphylactic activity of EEST and also elicited potent antioxidant activity. The antiallergic and anti-anphylactic activity might be due to inhibition of release of chemical mediators from mast cells largely by phytoconstituents like steroidal saponins, triterpenoids and flavonoids present in EEST.

Antihistaminic and antiallergic actions of extracts of Solanum nigrum berries: possible role in the treatment of asthma.

ETHNOPHARMACOLOGICAL RELEVANCE: Berries of the plant Solanum nigrum Linn (Solanaceae) are used for the treatment of asthma in folk medicine and ancient books. AIM OF STUDY: To evaluate potential of the plant berries in the treatment of asthma. MATERIALS AND METHODS: Petroleum ether, ethanol and aqueous extracts of S. nigrum berries (50, 100 and 200mg/kg, i.p.) were screened for the treatment of asthma by the various methods viz. effect on clonidine and haloperidol induced catalepsy, milk-induced leucocytosis and eosinophilia, mast cell stabilizing activity in mice and studies on smooth muscle preparation of guinea pig ileum (in vitro). Active petroleum ether extract was standardized by HPTLC. RESULTS: The petroleum ether extract of S. nigrum berries inhibited clonidine-induced catalepsy significantly but not haloperidol-induced catalepsy. Petroleum ether extract significantly inhibited increased leukocyte and eosinophil count due to milk allergen and showed maximum protection against mast cell degranulation by clonidine. Petroleum ether extract resisted contraction induced by histamine better than other extracts. All the results are dose dependant. Active petroleum ether extract showed presence of antiasthmatic compound, ß-sitosterol. CONCLUSION: The petroleum ether extract of S. nigrum berries can inhibits parameters linked to the asthma disease.

Effects of the antihistamine diphenhydramine on selected aquatic organisms.

In recent years pharmaceuticals have been detected in aquatic systems receiving discharges of municipal and industrial effluents. Although diphenhydramine (DPH) has been reported in water, sediment, and fish tissue, an understanding of its impacts on aquatic organisms is lacking. Diphenhydramine has multiple modes of action (MOA) targeting the histamine H1, acetylcholine (ACh), and 5-HT reuptake transporter receptors, and as such is used in hundreds of pharmaceutical formulations. The primary objective of this study was to develop a baseline aquatic toxicological understanding of DPH using standard acute and subchronic methodologies with common aquatic plant, invertebrate, and fish models. A secondary objective was to test the utility of leveraging mammalian pharmacology information to predict aquatic toxicity thresholds. The plant model, Lemna gibba, was not adversely affected at exposures as high as 10 mg/L. In the fish model, Pimephales promelas, pH affected acute toxicity thresholds and feeding behavior was more sensitive (no-observed-effect concentration = 2.8 µg/L) than standardized survival or growth endpoints. This response threshold was slightly underpredicted using a novel plasma partitioning approach and a mammalian pharmacological potency model. Interestingly, results from both acute mortality and subchronic reproduction studies indicated that the model aquatic invertebrate, Daphnia magna, was more sensitive to DPH than the fish model. These responses suggest that DPH may exert toxicity in Daphnia through ACh and histamine MOAs. The D. magna reproduction no-observed-effect concentration of 0.8 µg/L is environmentally relevant and suggests that additional studies of more potent antihistamines and antihistamine mixtures are warranted.

In vitro assessment of the cytotoxicity of anti-allergic eye drops using 5 cultured corneal and conjunctival cell lines.

The aim of this study was to evaluate the cytotoxicity of anti-allergic eye drops for human corneal endothelial cells (HCEC) and commercially available ocular surface cells. A primary HCEC culture was derived from human eye bank specimens. SIRC (rabbit corneal epithelium), BCE C/D-1b (bovine corneal epithelial cells), RC-1 (rabbit corneal epithelium), and Chang (human conjunctival cells) were obtained commercially. The WST-1 assay was used to measure HCEC viability, and the viability of other cells was measured using the MTT assay. Cells were treated with 7 commercially available anti-allergic eye drops for 48 h and cell viability was measured and calculated as a percentage of control. The degree of toxicity for each eye-drop solution was based on the cell viability score (CVS). HCECs treated with a 1000-fold dilution of the eye-drop solution had a viability score of 67% for Rizaben and ≥80% for the other solutions with Zepelin being the least toxic. Cell viability in response to eye-drop solutions preserved with benzalkonium chloride (BAK) was dependent on the concentration of the drug solution and exposure time. Treatment of ocular surface cells with a 20-fold dilution of the eye-drop solution resulted in the following order of cell viability as determined by their CVS: Zepelin > Ketas = Zaditen ≥ Tramelas PF = Patanol ≥ Rizaben ≥ Livostin. This order was similar to that observed for HCECs, and cell viability was found to be concentration-dependent. Based on the penetration of the drug into eye tissues, HCECs are only likely to be pharmaceutically damaging in rare cases. Epithelial cell viability depends primarily on the concentration of BAK rather than on the action of the active component in the eye-drop solution. CVS values were useful for comparison of toxicity.

Murine chronotoxicity to the antiallergic agent, cetirizine.

Cetirizine is a second-generation histamine H1-receptor antagonist used in the treatment of allergic diseases. The aim of the study was to assess whether cetirizine toxicity estimated by, for example, death, body loss, and leucopenia, is circadian rhythm dependent. A total of 210 male Swiss mice, aged 9 weeks, were synchronized for 3 weeks to 12-hour light (i.e., rest span)/12-hour dark (i.e., activity span) cycles. The drug was administered per os (orally). Each lethal (DL(50) = 750 mg/kg) and sublethal (DT(50) = 55 mg/kg) dose was administered to comparable groups of animals at six different circadian time points (1, 5, 9, 13, 17, and 21 hours after light onset; HALO). The death rate was dosing time dependent (P <0.001). Drug dosing at 5 HALO resulted in maximum mortality (76.75%), whereas dosing at 17 HALO resulted in the lowest mortality rate (16.7%). Cosinor analyses validated a statistically significant circadian rhythm in death rate (P < 0.008). Changes in body weight after cetirizine administration were dosing time dependent (P < 0.01), with the dosing time of least effect (-0.7% loss) at 17 HALO and of greatest effect (-7% loss) at 5 HALO. Cosinor analyses validated a statistically significant circadian rhythm in body loss (P < 0.05). A statistically significant decrease in leukocyte number varied, according to antihistamine dosing time (P < 0.01), with the dosing time of least leucopenia (≈-17%) at 17 HALO and of greatest leucopenia (≈-28%) at 5 HALO. The results show that cetirizine dosing time at the midactivity (dark) span seems to be optimal, since it corresponds to the best tolerance.

Anti-allergic, anti-inflammatory and anti-lipidperoxidant effects of Cassia occidentalis Linn.

Cassia occidentalis Linn. mast cell degranulation at a dose of 250 mg/kg, showed dose dependent stabilizing activity towards human RBC, with is widely used in traditional medicine of India to treat a number of clinical conditions including allergy and inflammatory manifestations. In the present study anti-allergic, anti-inflammatory and anti-oxidant properties of C. occidentalis whole plant ethanolic extract (CO) was investigated. Effects of CO on rat mast cell degranulation inhibition and human red blood cell (HRBC) membrane stabilization were studied in vitro following standard methods. The anti lipidperoxidant effects of CO were also studied in vitro. Effect of CO on carrageenan-induced mouse paw oedema inhibition was also assessed. CO significantly decreased maximum protection of 80.8% at 15 microg/ml. The extract also caused significant reduction in malondialdehyde (MDA) levels of murine hepatic microsomes at 100 microg/ml (56%) and significantly reduced carrageenan induced inflammation in mice at a dose of 250 mg/kg. Results of the present study indicated that CO inhibited mast cell degranulation, stabilized HRBC membrane thereby alleviating immediate hypersensitivity besides showing anti oxidant activity.

The inhaled glucocorticoid fluticasone propionate efficiently inactivates cytochrome P450 3A5, a predominant lung P450 enzyme.

Inhaled glucocorticoid (GC) therapy is a vital part of the management of chronic asthma. GCs are metabolized by members of the cytochrome P450 3A family in both liver and lung, but the enzymes are differentially expressed. Selective inhibition of one or more P450 3A enzymes could substantially modify target and systemic concentrations of GCs. In this study, we have evaluated the mechanism-based inactivation of P450 3A4, 3A5, and 3A7 enzymes by GCs. Among the five major inhaled GCs approved for clinical use in the United States, fluticasone propionate (FLT) was the most potent mechanism-based inactivator of P450 3A5, the predominant P450 enzyme in the lung. FLT inactivated P450 3A5 in a time- and concentration-dependent manner with K(I), k(inact), and partition ratio of 16 muM, 0.027 min(-1), and 3, respectively. In contrast, FLT minimally inactivated P450 3A4 and did not inactivate 3A7, even with a concentration of 100 muM. The inactivation of P450 3A5 by FLT was irreversible because dialysis did not restore enzyme activity. In addition, the exogenous nucleophilic scavenger GSH did not attenuate inactivation. The prosthetic heme of P450 3A5 was not modified by FLT. The loss of P450 3A5 activity in lung cells could substantially decrease the metabolism of FLT, which would increase the effective FLT concentration at its target site, the respiratory epithelium. Also, inactivation of lung P450 3A5 could increase the absorption of inhaled FLT, which could lead to high systemic concentrations and adverse effects, such as life-threatening adrenal crises or cataracts that have been documented in children receiving high doses of inhaled GCs.