Metabolism of LY654322, a growth hormone secretagogue, to an unusual diimidazopyridine metabolite.

2-Methylalanyl-N-{1-[(1R)-1-(4-fluorophenyl)-1-methyl-2-oxo-2-pyrrolidin-1-ylethyl]-1H-imidazol-4-yl}-5-phenyl-D-norvalinamide (LY654322) was rapidly cleared in rats and dogs by renal excretion of parent and metabolism (oxidative and hydrolytic). Among the metabolites identified in the urine of rats and dogs was M25, which was structurally unusual. Indeed, the characterization of M25 and investigation into its disposition relied on the convergence of diverse analytical methodologies. M25 eluted after the parent on reverse-phase chromatography with an MH(+) at m/z 598 (parent + 35 Da). Given its increased lipophilicity and its mass difference compared with the parent, it was evident that M25 was not a phase 2 conjugate. Subsequent liquid chromatography with multiple-stage tandem mass spectrometry and accurate mass experiments identified the structure of M25 as having two replicates of the 1-(4-fluorophenyl)-1-methyl-2-oxo-2-pyrrolidinyl substructure flanking a central aromatic core of composition C(7)H(3)N(5) that was refractory to fragmentation. Compared with the UV spectrum of the parent (λ(max) = 213 nm), M25 displayed a bathochromic shift (λ(max) = 311 nm), which substantiated extensive conjugation within the central core. Subsequent NMR analysis of M25 isolated from dog urine coupled with molecular modeling revealed the structure to be consistent with a diimidazopyridine core with two symmetrically substituted 1-(4-fluorophenyl)-1-methyl-2-oxo-2-pyrrolidinyl moieties. Using a structural analog with a chromophore similar to M25, LC-UV was used to quantitate M25 and determine its urinary disposition. The formation of M25 appears consistent with hydrolysis of LY654322 to an aminoimidazole, dimerization of the latter with the loss of NH(3), C-formylation, and subsequent ring closure and aromatization with loss of H(2)O.

Bioavailability of oral carisoprodol 250 and 350 mg and metabolism to meprobamate: A single-dose crossover study.

BACKGROUND: Carisoprodol is a skeletal muscle relaxant indicated for use in the treatment of acute, painful musculoskeletal conditions. Two randomized, controlled clinical trials have reported that carisoprodol 250 mg QID was equally effective as and better tolerated than carisoprodol 350 mg QID. OBJECTIVES: The primary objective of the current study was to determine the relative bioavailability of carisoprodol and its metabolite, meprobamate, with singledose administration of 250- and 350-mg tablets. A secondary objective of the study was to determine whether lowering the carisoprodol dose would decrease plasma meprobamate concentrations. METHODS: This single-dose, randomized, open-label, crossover study enrolled healthy volunteers. Each dose was administered with water in the morning; after a 7-day washout, subjects received the alternate dose. Blood samples were drawn at prespecified times over a 48-hour period. For tolerability assessment, subjects underwent a physical examination, including 12-lead ECG. RESULTS: A total of 24 subjects were enrolled (12 men, 12 women; mean age, 22.8 years). The dose-adjusted AUC0-∞ values for carisoprodol were 5.29 µg/mL/h with the 250-mg tablet and 5.75 µg/mL/h with the 350-mg tablet (relative bioavailability, 92%). The mean (SD) Cmax values of carisoprodol and meprobamate after administration of the 250-mg carisoprodol tablet were 1.24 (0.49) and 1.84 (0.31) µg/mL, respectively, compared with 1.78 (0.97) and 2.46 (0.47) µg/mL with the 350-mg tablet. AUC0-∞ was dose proportional, and the apparent t1/2 values at the terminal phase were 1.74 hours with the 250-mg tablet and 1.96 hours with the 350-mg tablet. There were 3 mild adverse events considered possibly treatment related (weakness, dizziness, and drowsiness); these were reported in 2 subjects with 350-mg carisoprodol. CONCLUSIONS: In this small study in healthy fasting subjects, the exposure to carisoprodol and meprobamate was dose proportional between the single 250- and 350-mg doses. Both doses were generally well tolerated.

Open-label evaluation of azelastine nasal spray in patients with seasonal allergic rhinitis and nonallergic vasomotor rhinitis.

OBJECTIVE: The objective of the study was to evaluate the effectiveness of azelastine (Astelin) nasal spray, a topical second-generation antihistamine, in the treatment of symptoms of seasonal allergic rhinitis, seasonal allergic rhinitis with nonallergic triggers (mixed rhinitis), and nonallergic vasomotor rhinitis. RESEARCH DESIGN AND METHODS: A total of 2343 primary care physicians, allergists, ENT specialists, and other health professionals participated in this 2-week, open-label evaluation of azelastine nasal spray. Data were collected through a physician questionnaire that included patient demographics, rhinitis diagnosis, medication history, and inclusion/exclusion criteria; and two patient questionnaires that included symptom history, response to previous rhinitis medications, symptom control, and level of satisfaction with azelastine nasal spray. A completed physician questionnaire and two completed patient questionnaires were required for each patient to be included in the analysis. Patients who qualified for enrollment were given open-label azelastine nasal spray and instructed to administer 2 sprays per nostril twice daily for 2 weeks. RESULTS: A total of 1225 health professionals enrolled 7864 patients into the study. Completed physician and patient questionnaires were returned by 1081 health professionals and 5073 patients, 4364 of whom used azelastine nasal spray as their only rhinitis medication during the 2-week study period. The patients were predominantly caucasian (82.6%) and female (61.1%), with a mean age of 50 years. The majority had a diagnosis of mixed rhinitis (51.5%), followed by seasonal allergic rhinitis (32.3%), and nonallergic (vasomotor) rhinitis (16.2%). After 2 weeks of treatment, the percentage of patients reporting some control or complete control of individual symptoms ranged from 78% for postnasal drip in patients with nonallergic vasomotor rhinitis to 90% for sneezing in patients with seasonal allergic rhinitis. More than 85% of patients who reported difficulty sleeping or impairment of daytime activities due to rhinitis symptoms had improvement in these parameters. Azelastine nasal spray was well tolerated, the discontinuation rate due to adverse events was 2.3%. CONCLUSIONS: Azelastine nasal spray was reported to control all rhinitis symptoms, including nasal congestion, regardless of rhinitis diagnosis during the 2-week study period. Patients with seasonal allergic rhinitis and patients with seasonal allergic rhinitis plus nonallergic triggers were identified as patient types most likely to respond to azelastine nasal spray.

Simultaneous quantification of atomoxetine as well as its primary oxidative and O-glucuronide metabolites in human plasma and urine using liquid chromatography tandem mass spectrometry (LC/MS/MS).

A sensitive and selective liquid chromatography tandem mass spectrometry (LC/MS/MS) method for the determination of atomoxetine and its metabolites (4-hydroxyatomoxetine, N-des-methylatomoxetine, and 4-hydroxyatomoxetine-O-glucuronide) has been developed for human plasma and urine. Using stable-labeled internal standards, the method proved to be accurate and precise for the analytes in all species, resulting in inter-batch accuracy (percent relative error, %RE) within 100+/-13% and inter-batch precision (relative standard deviation, %RSD) within 11%. Stability was demonstrated for the analytes in neat solutions and the reconstitution solvent, as well as plasma and urine (with or without the deconjugation reagent). The method was simple, robust (utilized for the analysis of several hundred clinical study samples), and amenable to high sample throughput.

Na+-dependent high affinity binding of [3H]LY515300, a 3,4-dimethyl-4-(3-hydroxyphenyl)piperidine opioid receptor inverse agonist.

Analogues of 3,4-dimethyl-4-(3-hydroxyphenyl)piperidines are high affinity inverse agonists for micro-, delta- and kappa-opioid receptors. To characterize inverse agonist binding, we synthesized a high specific activity radioligand from this series, [3H]LY515300 (3-[1-((3-cyclohexyl-[3,4-3H(2)])-3(R,S)-hydroxypropyl)-3(R),4(R)-dimethylpiperidin-4-yl]phenol). In membranes expressing cloned human opioid receptors, [3H]LY515300 binding was saturable and exhibited low nonspecific binding. [3H]LY515300 bound with high affinity to the micro- (K(d)=0.07 nM), delta- (K(d)=0.92 nM) and kappa-(K(d)=0.45 nM) opioid receptors. High affinity [3H]LY515300 binding to all opioid receptors was Na(+)-dependent, a characteristic of inverse agonists. Displacement by standard opioid compounds yielded K(i) values consistent with their known opioid receptor affinities. Autoradiographic localization of specific [3H]LY515300 binding in rat and guinea pig brain was high in areas known to express high levels of opioid (particularly micro-opioid receptor) binding sites including the caudate, nucleus accumbens, and nucleus tractus solitarius. Thus, [3H]LY515300 is the first radiolabeled opioid receptor inverse agonist useful for the study of opioid receptors in cell lines and native tissues.

Evaluation of [3H]LY341495 for labeling group II metabotropic glutamate receptors in vivo.

New glutamatergic drugs are being developed as potential therapies for neurodegenerative disorders, anxiety disorders, and psychoses. The development of effective mGluR radiotracers would provide essential tools with which to probe these sites in living humans, providing critical information about certain disease processes involving the glutamaterigic system and its regulation in humans. As a first step towards this goal, the tritiated form of the high affinity group II metabotropic glutamate receptor (mGluR) antagonist LY341495 [K(D) (mGluR(2)) = 1.67 +/- 0.20 nM, K(D) (mGluR(3)) = 0.75 +/- 0.43 nM] was evaluated to determine its potential to label mGluRs in vivo. Dissection analysis of the regional brain distribution over time of [(3)H]LY341495 in male rats revealed low brain uptake and no significant demonstrable saturable binding of this tracer. A group II mGluR tracer possessing higher affinity than [(3)H]LY341495 and an absence of carboxylic acid groups is likely required for in vivo PET imaging purposes.

Randomized, double-blind trial of carisoprodol 250 mg compared with placebo and carisoprodol 350 mg for the treatment of low back spasm.

BACKGROUND: Carisoprodol, a centrally active skeletal muscle relaxant, is widely used for the treatment of acute, painful musculoskeletal disorders. When administered at a dose of 350 mg four times daily, carisoprodol demonstrated significant clinical benefit in its early clinical development trials; however, some unfavorable side effects, such as drowsiness and dizziness, were reported. Recently, research was conducted to determine if a lower dose of carisoprodol would retain efficacy but improve tolerability compared to the higher 350-mg dose. OBJECTIVE: The purpose of this multicenter study was to compare the efficacy and safety of carisoprodol 250-mg tablets four times daily to 350-mg tablets four times daily and to placebo in patients with acute, painful musculoskeletal spasm of the lower back. RESEARCH DESIGN AND METHODS: In this 1-week double-blind, placebo-controlled, parallel-group multicenter trial, patients 18 to 65 years of age with moderate to severe back spasm were randomly assigned to treatment with carisoprodol 250-mg tablets (n = 264), 350-mg tablets (n = 273), or matching placebo tablets (n = 269) three times daily and at bedtime. MAIN OUTCOME MEASURES: The coprimary efficacy variables were patient-rated relief from starting backache and patient-rated global impression of change assessed on treatment day 3. RESULTS: The carisoprodol 250-mg regimen was significantly more effective than placebo as assessed by both patient-rated relief from starting backache (p = 0.0001) and patient-rated global impression of change (p = 0.0046). There were no significant differences between the 250-mg and 350-mg dosages for the coprimary efficacy endpoints, and patients improved with or without sedation. Fewer than 1% of patients in the carisoprodol 250-mg group discontinued prematurely because of treatment-emergent adverse events, and no patient discontinued because of drowsiness. CONCLUSIONS: When administered three times daily and at bedtime, carisoprodol 250 mg was as effective as 350 mg three times daily and at bedtime with a lower incidence of adverse events and fewer discontinuations of therapy due to adverse events. Patients improved whether or not they reported sedation as an adverse event.

Novel pharmacologic approaches to the management of sepsis: targeting the host inflammatory response.

Sepsis is currently the 10(th) leading cause of death overall and accounts for significant healthcare expenditures in the developed world. There are now more deaths attributable to sepsis than coronary artery disease, stroke, or cancer, and it is widely believed that the incidence of sepsis and sepsis-related mortality will continue to rise. Based on these sobering statistics, there is great interest in identifying novel treatments for managing critically ill children and adults with sepsis. Unfortunately, to date, there have been very few successful therapeutic agents employed in the clinical setting. Despite these disappointing results, new therapeutic agents continue to be identified, and there is reason for optimism and hope for the future. Herein, we will briefly review several novel therapeutic adjuncts for the management of critically ill patients with sepsis. We will largely focus on those therapies that directly target the host inflammatory response, specifically those that result in activation of the transcription factor, nuclear factor (NF)-kappaB. We will also reference some of the patents recently filed that pertain to the host innate immune response and sepsis.

Double-blind, placebo-controlled trial of reformulated azelastine nasal spray in patients with seasonal allergic rhinitis.

BACKGROUND: Azelastine nasal spray is a topical antihistamine with a distinctive taste that may be objectionable to some patients. The primary objectives of this clinical trial were (1) to determine if a reformulated azelastine nasal spray (Astepro) with sucralose as a taste-masking agent provides comparable efficacy to the original formulation (Astelin) and (2) to evaluate dose-response relationships between groups. METHODS: Eight hundred thirty-five patients with seasonal allergic rhinitis were randomized to six treatment groups: (1) original azelastine nasal spray, 1 spray/nostril b.i.d.; (2) reformulated azelastine, 1 spray/nostril b.i.d.; (3) placebo, 1 spray/ nostril b.i.d.; (4) original azelastine nasal spray, 2 sprays/nostril b.i.d., (5) reformulated, 2 sprays/nostril b.i.d.; and (6) placebo, 2 sprays/nostril b.i.d. The primary efficacy variable was the change from baseline to day 14 in total nasal symptom score (TNSS) consisting of runny nose, sneezing, itchy nose, and nasal congestion. RESULTS: Original azelastine nasal spray and the reformulated spray produced comparable improvements in the TNSS at both dosages. There was a dose-related difference in TNSS comparing the 1- and 2-spray dosages. The percentage changes from baseline in the TNSS in the 2-sprays/nostril dosage groups were 27.9% (p<0.001) with the reformulated nasal spray, 23.5% (p<0.01) with the original formulation, and 15.4% with placebo. The incidence of bitter taste was 7% with the reformulated spray and 8% with the original at the 2-sprays/nostril dosage. CONCLUSION: The results of this study showed efficacy both with original azelastine nasal spray and with the reformulated nasal spray and a clear dose-response difference between the 1- and 2-spray dosages.

(2S,1'S,2'R,3'R)-2(2'-Carboxy-3'-hydroxymethylcyclopropyl)glycine-[3H], a potent and selective radioligand for labeling group 2 and 3 metabotropic glutamate receptors.

We report herein the synthesis of the tritium labeled isotopomer of 1 and its use as a radioligand to label mGlu8 receptors in rat forebrain membranes as well as cloned human recombinant mGlu receptors. [(3)H]-1 was synthesized by the NaBT(4) reduction of an activated analog of 5. [(3)H]-1 bound appreciably to recombinant human mGlu2, mGlu3 and mGlu8 receptors and to rat forebrain membranes and was displaced by L-glutamate and L-(+)-2 amino-4-phosphonobutyric acid. The results indicate that [(3)H]-1 should be a useful ligand for the study of mGluR2, 3, and 8 receptors in cloned cell lines and possibly brain tissue.

Efficacy of azelastine nasal spray in seasonal allergic rhinitis patients who remain symptomatic after treatment with fexofenadine.

BACKGROUND: Currently available oral second-generation antihistamines do not provide adequate symptom relief for many allergy patients. OBJECTIVE: To determine the ability of azelastine nasal spray to improve rhinitis symptoms in patients with seasonal allergic rhinitis who remained symptomatic after treatment with fexofenadine. METHODS: This was a multicenter, randomized, double-blind, placebo-controlled, 2-week study in patients with moderate-to-severe seasonal allergic rhinitis. The study began with a 1-week, open-label lead-in period, during which patients received fexofenadine, 60 mg twice daily. Patients who improved less than 25% to 33% with fexofenadine were randomized to treatment with (1) azelastine nasal spray, 2 sprays per nostril twice daily; (2) azelastine nasal spray, 2 sprays per nostril twice daily, plus fexofenadine, 60 mg twice daily; or (3) placebo (saline) nasal spray and placebo capsules twice daily. The primary efficacy variable was the change from baseline to day 14 in the total nasal symptom score (TNSS), consisting of runny nose, sneezing, itchy nose, and nasal congestion symptom scores. RESULTS: A total of 334 patients who remained symptomatic after treatment with fexofenadine were included in the efficacy analysis. After 2 weeks of treatment, azelastine nasal spray (P = .007) and azelastine nasal spray plus fexofenadine (P = .003) significantly improved the TNSS compared with placebo. Azelastine nasal spray monotherapy was as effective as the combination of azelastine nasal spray plus fexofenadine as measured by the TNSS and individual symptoms of the TNSS. CONCLUSIONS: Azelastine nasal spray is effective monotherapy for patients who remain symptomatic after treatment with fexofenadine and should be considered in the initial management of patients with seasonal allergic rhinitis.

The disposition, metabolism, and pharmacokinetics of a selective metabotropic glutamate receptor agonist in rats and dogs.

Compound LY354740 [(+)-2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylic acid], an analog of glutamic acid, is a selective group 2 metabotropic glutamate receptor agonist in clinical development for the treatment of anxiety. Studies have been conducted to characterize the absorption, disposition, metabolism, and excretion of LY354740 in rats and dogs after intravenous bolus or oral administration. Plasma concentrations of LY354740 were measured using a validated gas chromatography/mass spectrometry assay. In rats, LY354740 demonstrated linear pharmacokinetics after oral administration from 30 to 1000 mg/kg. The oral bioavailability of LY354740 was approximately 10% in rats and 45% in dogs. In the dog, food decreased the mean area under the plasma concentration-time curve value by approximately 34%, hence, decreasing the oral bioavailability of the compound. Excretion studies in both rats and dogs indicate that the absorbed drug is primarily eliminated via renal excretion. In addition, tissue distribution in rats showed that the highest levels of radioactivity were in the kidney and gastrointestinal tract, which is consistent with the excretion studies. Metabolism of LY354740 was evaluated in vitro using rat and dog liver microsomes and rat liver slices. In addition, urine and fecal samples from rat and dog excretion studies were profiled using HPLC with radio-detection. These evaluations indicated that neither rats nor dogs metabolized LY354740. In summary, LY354740 is poorly absorbed in rats, moderately absorbed in dogs, and rapidly excreted as unchanged drug in the urine.

Disposition and metabolic fate of atomoxetine hydrochloride: pharmacokinetics, metabolism, and excretion in the Fischer 344 rat and beagle dog.

These studies were designed to characterize the disposition and metabolism of atomoxetine hydrochloride [(-)-N-methyl-gamma-(2-methylphenoxy)benzenepropanamine hydrochloride; formerly know as tomoxetine hydrochloride] in Fischer 344 rats and beagle dogs. Atomoxetine was well absorbed from the gastrointestinal tract and cleared primarily by metabolism with the majority of its metabolites being excreted into the urine, 66% of the total dose in the rat and 48% in the dog. Fecal excretion, 32% of the total dose in the rat and 42% in the dog, appears to be due to biliary elimination and not due to unabsorbed dose. Nearly the entire dose was excreted within 24 h in both species. In the rat, low oral bioavailability was observed (F = 4%) compared with the high oral bioavailability in dog (F = 74%). These differences appear to be almost purely mediated by the efficient first-pass hepatic clearance of atomoxetine in rat. The biotransformation of atomoxetine was similar in the rat and dog, undergoing aromatic ring hydroxylation, benzylic oxidation (rat only), and N-demethylation. The primary oxidative metabolite of atomoxetine was 4-hydroxyatomoxetine, which was subsequently conjugated forming O-glucuronide and O-sulfate (dog only) metabolites. Although subtle differences were observed in the excretion and biotransformation of atomoxetine in rats and dogs, the primary difference observed between these species was the extent of first-pass metabolism and the degree of systemic exposure to atomoxetine and its metabolites.