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Identification of human UDP-glucuronosyltransferase enzyme(s) responsible for the glucuronidation of 3-hydroxydesloratadine.

Ghosal A, Yuan Y, Hapangama N, Su AD, Alvarez N, Chowdhury SK, Alton KB, Patrick JE, Zbaida S.

Drug Metabolism and Pharmacokinetics, Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA. anima.ghosal spcorp.com

Desloratadine is a non-sedating antihistamine recently approved for the treatment of seasonal allergic rhinitis. The major metabolite of desloratadine in human plasma and urine is the glucuronide conjugate of 3-hydroxydesloratadine. 3-Hydroxydesloratadine-glucuronide is also the major in vitro metabolite of 3-hydroxydesloratadine formed by incubation of 3-hydroxydesloratadine with human liver microsomes supplemented with uridine 5'-diphosphate-glucuronic acid (UDPGA). The metabolite structure was confirmed by LC-MS and LC-MS/MS. Out of ten recombinant human UDP-glucuronosyltransferases (UGTs), UGT1A1, UGT1A3, UGT1A8 and UGT2B15 exhibited catalytic activity with respect to the formation of 3-hydroxydesloratadine-glucuronide. Inhibition studies with known inhibitors of UGT (diclofenac, flunitrazepam and bilirubin) confirmed the involvement of UGT1A1, UGT1A3 and UGT2B15 in the formation of 3-hydroxydesloratadine-glucuronide. The results from this study demonstrated that the in vitro formation of 3-hydroxydesloratadine-glucuronide from 3-hydroxydesloratadine was mediated via UGT1A1, UGT1A3 and UGT2B15 in human liver.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15334623&dopt=Abstract desloratadine Clarinex



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Desloratadine partially inhibits the augmented bacterial responses in the sinuses of allergic and infected mice.

Kirtsreesakul V, Blair C, Yu X, Thompson K, Naclerio RM.

Department of Surgery, Section of Otolaryngology-Head and Neck Surgery, The University of Chicago, Chicago, IL 60637, USA.

BACKGROUND: Allergic rhinitis (AR) is considered a major predisposing factor for the development of acute bacterial rhinosinusitis. How AR augments a bacterial infection is unknown. OBJECTIVE: Our purpose in this study was to test whether an H1 receptor antagonist, desloratadine, could reduce the augmented effect of an ongoing allergic reaction on acute bacterial rhinosinusitis. METHODS: Three groups of infected and ovalbumin (OVA)-sensitized mice were studied: (1) infected and allergic mice treated with desloratadine, (2) infected and allergic mice treated with placebo, and (3) infected mice. A fourth group of uninfected, non-sensitized mice served as a control for the cellular changes. BALB/c mice were sensitized by two intraperitoneal injections of OVA given 8 days apart. One day after the second injection, the mice were nasally exposed daily to 6% OVA (the groups treated with desloratadine or placebo) or phosphate-buffered saline (PBS) (the infection-only group) for 5 days. After the second OVA exposure, the mice were intranasally inoculated with Streptococcus pneumoniae. Desloratadine or placebo was given daily throughout the OVA exposure period. Nasal allergic symptoms were observed by counting of nasal rubbing and sneezing for 10 min after OVA or PBS nasal challenge. On day 5 post-infection, nasal lavage culture was done, and the inflammatory cells in the sinuses were evaluated by flow cytometry. RESULTS: Mice that were made allergic, infected, and treated with placebo showed more organisms and phagocytes than did only infect mice. They also manifested allergic nasal symptoms and eosinophil influx into the sinuses. Desloratadine treatment during allergen exposure reduced allergic symptoms and reduced sinonasal infection (P<0.05). There tended to be less myeloid cell and neutrophil influx (P=0.09 both), but not eosinophil influx (P=0.85) compared with that in the placebo-treated group. CONCLUSION: Desloratadine treatment during nasal challenge inhibited allergic symptoms and reduced sinonasal infection, suggesting that histamine via an H1 receptor plays a role in the augmented infection in mice with an ongoing allergic reaction.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15479283&dopt=Abstract desloratadine Clarinex



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Desloratadine inhibits constitutive and histamine-stimulated nuclear factor-kappaB activity consistent with inverse agonism at the histamine H1 Receptor.

Wu RL, Anthes JC, Kreutner W, Harris AG, West RE Jr.

Schering-Plough Research Institute, Schering-Plough Corporation, Kenilworth, NJ 07033, USA.

BACKGROUND: The human histamine H1 receptor is constitutively active and exhibits basal activation of nuclear factor-kappaB (NF-kappaB), an important modulator of allergic inflammation. Certain H1 antihistamines have recently been shown to inhibit basal NF-kappaB activity by stabilizing the H1 receptor in an inactive state, a phenomenon called 'inverse agonism'. METHODS: We evaluated the effect of the new H1 antihistamine, desloratadine, on basal and histamine-stimulated NF-kappaB activity and compared it with the activities of other H1 antihistamines. RESULTS: Transiently transfected COS-7 cells co-expressing NF-kappaB-luciferase and the H1 receptor exhibited constitutive NF-kappaB activity. H1 antihistamines reduced basal NF-kappaB activity (rank order of potency: desloratadine > pyrilamine > cetirizine > loratadine > fexofenadine). Histamine stimulated basal NF-kappaB activity 8-fold, which was blocked by H1 antihistamines (rank order of potency: desloratadine > cetirizine > pyrilamine > loratadine > fexofenadine). Neither histamine nor antihistamines had any effect on NF-kappaB activity in the absence of the H1 receptor. CONCLUSIONS: Desloratadine, acting through the histamine H1 receptor, inhibited basal NF-kappaB activity and can thus be classified as an inverse agonist. Inhibition of basal and histamine-stimulated NF-kappaB activity may help to explain previously reported inhibitory effects of desloratadine on allergic inflammatory mediators. 2004 S. Karger AG, Basel.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15564772&dopt=Abstract desloratadine Clarinex



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Inhibition of nasal polyp mast cell and eosinophil activation by desloratadine.

Kowalski ML, Lewandowska A, Wozniak J, Makowska J, Jankowski A, DuBuske L.

Department of Clinical Immunology and Allergy, Faculty of Medicine, Medical University, Lodz, Poland.

Nasal polyp tissue which contains mast cells and eosinophils is similar to the inflamed airway mucosa in cellular composition and mediator content. This investigation assessed the effect of desloratadine (DL), on activation of cells in nasal polyp tissue. Polyps were obtained from 22 patients with chronic rhinosinusitis [nine aspirin acetylosalitic acid (ASA)-sensitive and 13 ASA-tolerant]. Polyp tissue was dispersed by digestion, and preincubated with DL and incubated with anti-immunoglobulin E (IgE) or calcium ionophore. LTC4, eosinophil cationic protein (ECP) and tryptase concentrations in supernatants were measured by immunoassays. Desloratadine (1, 10 and 50 microM) inhibited calcium ionophore-induced LTC4 release by a mean of 29%, 50% and 63% respectively, and anti-IgE-induced LTC4 release by a mean of 27%, 35% and 39% respectively. Calcium ionophore-induced tryptase release was inhibited 60% and 69% by 10 and 50 microM of DL, respectively, and anti-IgE-induced tryptase release was inhibited 33%, 47% and 66% for 1, 10 and 50 microM of DL. Desloratadine 10 microM and 50 microM inhibited ECP release by and 45% and 48% respectively. Polyp tissue from ASA-sensitive patients when compared with ASA-tolerant patients released at baseline significantly more ECP (medians 120.0 microg/ml, range: 69.0-182.0 vs 63.4 microg/ml, range: 3.7-172.0; P <0.05), but similar amounts of tryptase and LTC4. This study demonstrated that DL inhibits activation of both eosinophils and mast cells derived from a site of airway mucosal inflammation.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15575935&dopt=Abstract desloratadine Clarinex