Novel 2-(4-methylsulfonylphenyl)pyrimidine derivatives as highly potent and specific COX-2 inhibitors.

New series of 2-(4-methylsulfonylphenyl) and 2-(4-sulfamoylphenyl)pyrimidines were synthesized and evaluated for their ability to inhibit cyclooxygenase-2 (COX-2). COX-1 and COX-2 inhibitory activity of these compounds was determined using purified enzyme (PE) and human whole blood (HWB) assays. Extensive structure-activity relationship (SAR) work was carried out within these series, and a wide number of potent and specific COX-2 inhibitors were identified (HWB COX-2 IC(50)=2.4-0.3nM and 80- to 780-fold more selective than rofecoxib).

Design, syntheses, biological evaluation, and docking studies of 2-substituted 5-methylsulfonyl-1-phenyl-1H-indoles: potent and selective in vitro cyclooxygenase-2 inhibitors.

Four series of 5-methylsulfonyl-1-phenyl-1H-indole-2-carboxylic acid alkyl esters (family A), -2-carbonitriles (family B), -2-carboxamides (family C), and 2-benzoyl-5-methylsulfonyl-1-phenyl-1H-indoles (family D) were prepared and evaluated for their ability to inhibit purified cyclooxygenase-2 (COX-2) and cyclooxygenase-1 (COX-1). Family D compounds have the best COX-1/COX-2 inhibition ratios and potencies. According to docking studies, these molecules appear to bind the COX-2 binding site differently than indomethacin, with the insertion of the substituent at the 2-position in the hydrophobic pocket of the enzyme and the 1-position phenyl ring in the trifluoromethyl zone. Among the group of compounds evaluated, 2-(4-chlorobenzoyl)-1-(4-chlorophenyl)-5-methylsulfonyl-1H-indole and 2-(4-chlorophenyl)-5-methylsulfonyl-1-(4-trifluoromethylphenyl)-1H-indole emerged as the most potent (respective IC(50) values: 46 and 43 nM), and selective (respective selectivity indexes: >2163 and >2331) COX-2 inhibitors.

Reversal of learned helplessness by selective serotonin reuptake inhibitors in rats is not dependent on 5-HT availability.

Serotonin (5-HT) and 5-HT(1A) receptors have been suggested to play a pivotal role in the mechanism of action of antidepressant drugs, particularly in the case of selective serotonin reuptake inhibitors (SSRIs). In the rat learned helplessness (LH) paradigm, a valid animal model of human depression, repeated treatment with the 5-HT(1A) receptor agonist 8-OH-DPAT (0.125 and 0.5mg/kg) and several classes of antidepressants such as the tricyclic agent desipramine (30 and 60mg/kg), the monoamine oxidase inhibitor (MAOI) pargyline (60mg/kg) and the SSRIs fluoxetine (15 and 30mg/kg), paroxetine (15 and 30mg/kg) and sertraline (30mg/kg) improved behavioural deficit in helpless rats. The involvement of serotonergic mechanisms in the antidepressant-like effect of these agents was investigated using the selective 5-HT(1A) receptor antagonist WAY 100,635 and the 5-HT synthesis inhibitor p-chlorophenylalanine (PCPA). Pretreatment with WAY 100,635 blocked the 8-OH-DPAT-induced reduction in escape failures, but did not counteract the antidepressant effect of fluoxetine and paroxetine. PCPA given alone did not modify helpless behaviour nor did it affect the behavioural effect of 8-OH-DPAT, fluoxetine and paroxetine. Adaptive changes in 5-HT(1A) receptor function were studied by measuring 8-OH-DPAT-mediated hypothermia and lower lip retraction (LLR) in the animals 24h after LH test session. Fluoxetine and paroxetine treatments caused a marked reduction in agonist-induced responses, an effect completely prevented by WAY 100,635 and PCPA. In conclusion, whereas direct agonist activity at postsynaptic 5-HT(1A) receptors attenuated helpless behaviour, the antidepressant-like effect of SSRIs was found to be independent of their actions on either 5-HT(1A) receptor function or extracellular 5-HT.

Genotoxic activity of halogenated phenylglycine derivatives.

The discovery of genotoxic amino acids derived from phenylglycine, and possessing halogen substituents, is described. The utility of hypervalent iodine reagents in the synthesis of this class of compounds is highlighted. The mechanism of action of the (haloaryl)glycines was studied in Saccharomyces cerevisiae.

In vivo pharmacological characterisation of bilastine, a potent and selective histamine H1 receptor antagonist.

OBJECTIVE: We set out to establish the in vivo histamine H(1) receptor antagonistic (antihistaminic) and antiallergic properties of bilastine. METHODS: In vivo antihistaminic activity experiments consisted of measurement of: inhibition of increase in capillary permeability and reduction in microvascular extravasation and bronchospasm in rats and guinea pigs induced by histamine and other inflammatory mediators; and protection against lethality induced by histamine and other inflammatory mediators in rats. In vivo antiallergic activity experiments consisted of measurement of passive and active cutaneous anaphylactic reactions as well as type III and type IV allergic reactions in sensitised rodents. RESULTS: In the in vivo antihistaminic activity experiments, bilastine was shown to have a positive effect, similar to that of cetirizine and more potent than that of fexofenadine. The results of the in vivo antiallergic activity experiments showed that the properties of bilastine in this setting are similar to those observed for cetirizine and superior to fexofenadine in the model of passive cutaneous anaphylactic reaction. When active cutaneous anaphylactic reaction experiments were conducted, bilastine showed significant activity, less potent than that observed with cetirizine but superior to that of fexofenadine. Evaluation of the type III allergic reaction showed that of the antihistamines only bilastine was able to inhibit oedema in sensitised mice, although its effect in this respect was much less potent than that observed with dexamethasone. In terms of the type IV allergic reaction, neither bilastine, cetirizine nor fexofenadine significantly modified the effect caused by oxazolone. CONCLUSIONS: The results of our in vivo preclinical studies corroborate those obtained from previously conducted in vitro experiments of bilastine, and provide evidence that bilastine possesses antihistaminic as well as antiallergic properties, with similar potency to cetirizine and superior potency to fexofenadine.

In vitro and in vivo characterization of F-97013-GD, a partial 5-HT1A agonist with antipsychotic- and antiparkinsonian-like properties.

In order to better define the role of 5-HT(1A) receptors in the modulation of extrapyramidal motor functions, we investigated the effect of 5-HT(1A) agonists on tacrine-induced tremulous jaw movements (TJM) in rats, a putative model of parkinsonian tremor. Acute injection of 5-HT(1A) agonists 8-OH-DPAT and buspirone dose-dependently counteracted the tacrine-induced oral movements (ED(50)=0.04 and 1.0mg/kg, respectively), an effect reversed by the selective 5-HT(1A) antagonist WAY 100,635. In contrast to classical antipsychotics, the atypical antipsychotics risperidone (ED(50)=0.3mg/kg) and clozapine (ED(50)=1.5mg/kg) blocked the oral movements induced by the cholinomimetic agent at or below the doses required for suppression of conditioned avoidance response. The compound F-97013-GD (6-methyl-2-[4-(naphtylpiperazin-1-yl)butyl]-3-(2H)-pyridazinone), a putative antipsychotic drug that in functional in vitro and in vivo assays behaved as a mixed dopamine D(2)-antagonist and 5-HT(1A)-partial agonist, also displayed a potent antitremorgenic effect in this paradigm (ED(50)=0.5mg/kg). Interestingly, pretreatment with WAY 100,635 blocked the inhibitory effect of F-97013-GD but not that of clozapine. The 5-HT depleting agent para-chlorophenylalanine (PCPA) partially attenuated tacrine-induced TJM but did not block the suppressive effect of 5-HT(1A) agonists. In addition, only high doses of F-97013-GD induced catalepsy in rodents and, like 8-OH-DPAT and clozapine, the compound reversed the haloperidol-induced catalepsy in rats. These results show that 5-HT(1A) receptors play a role in the regulation of tacrine-induced TJM and suggest that their activation by novel antipsychotics may not only reduce the extrapyramidal side effects EPS liability, but also be effective in the treatment of parkinsonian tremor.

Preclinical pharmacology of bilastine, a new selective histamine H1 receptor antagonist: receptor selectivity and in vitro antihistaminic activity.

OBJECTIVE: This study aimed to establish the receptor selectivity and antihistaminic activity of bilastine, a new selective antihistamine receptor antagonist. DESIGN AND METHODS: In vitro experiments were conducted using a receptor binding screening panel and guinea-pig and rat tissues. Antihistaminic activity was determined using H1 receptor binding studies and in vitro H1 antagonism studies conducted in guinea-pig tissues and human cell lines. Receptor selectivity was established using a receptor binding screening panel and a receptor antagonism screening conducted in guinea-pig, rat and rabbit tissues. Inhibition of inflammatory mediators was determined through the Schultz-Dale reaction in sensitised guinea-pig ileum. RESULTS: Bilastine binds to histamine H1-receptors as indicated by its displacement of [3H]-pyrilamine from H1-receptors expressed in guinea-pig cerebellum and human embryonic kidney (HEK) cell lines. The studies conducted on guinea-pig smooth muscle demonstrated the capability of bilastine to antagonise H1-receptors. Bilastine is selective for histamine H1-receptors as shown in receptor-binding screening conducted to determine the binding capacity of bilastine to 30 different receptors. The specificity of its H1-receptor antagonistic activity was also demonstrated in a series of in vitro experiments conducted on guinea-pig and rat tissues. The results of these studies confirmed the lack of significant antagonism against serotonin, bradykinin, leukotriene D4, calcium, muscarinic M3-receptors, alpha1-adrenoceptors, beta2-adrenoceptors, and H2- and H3-receptors. The results of the in vitro Schultz-Dale reaction demonstrated that bilastine also has anti-inflammatory activity. CONCLUSIONS: These preclinical studies provide evidence that bilastine has H1- antihistamine activity, with high specificity for H1-receptors, and poor or no affinity for other receptors. Bilastine has also been shown to have anti-inflammatory properties.

Pharmacokinetic-pharmacodynamic modeling of the hydroxy lerisetron metabolite L6-OH in rats: an integrated parent-metabolite model.

PURPOSE: The twofold aim of this study was to characterize in vivo in rats the pharmacokinetics (PK) and pharmacodynamics (PD) of L6-OH, a metabolite of lerisetron with in vitro pharmacological activity, and evaluate the extent to which L6-OH contributes to the overall effect. METHODS: The PK of L6-OH was determined directly postmetabolite i.v. dose (PK-1), and also simultaneously for L (lerisetron concentration) and for generated L6-OH after lerisetron dose (200 microg kg(-1), i.v.), using Nonlinear Mixed Effects Modeling with an integrated parent-metabolite PK model (PK-2). Surrogate effect was measured by inhibition of serotonin-induced bradycardia. Protein binding was assayed via ultrafiltration and all quantification was performed via liquid chromatography-electrospray ionization-mass spectrometry. RESULTS: L6-OH showed elevated plasma and renal clearances, and volume of distribution (PK-1). The in vivo potency (PD) of L6-OH was high (EC(50) = 0.098 ng mL(-1) and EC(50unbound) = 0.040 ng mL(-1)). Total clearance for L (PK-2) in the presence of generated L6-OH (CL(L) = CL(-->L6-OH) + CL(n)) was 0.0139 L min(-1). Most of this clearance was L6-OH formation (F(c) = 99.6%), but only an 8.6% fraction of L6-OH was released into the bloodstream. The remainder undergoes biliar and fecal elimination. The parameters estimated from PK-2 were used to predict concentrations of L6-OH (Cp(L6)) generated after a lerisetron therapeutic dose (10 microg kg(-1)) in the rat. These concentrations are needed for the PD model and are below the quantification limit. Cp(L6max) was less than the EC(50) of L6-OH. CONCLUSIONS: We conclude that after lerisetron administration, L6-OH is extensively formed in the rat but it is quickly eliminated; therefore, besides being equipotent with the parent drug, the L6-OH metabolite does not influence the effect of lerisetron.

Preclinical pharmacology of F-98214-TA, a novel potent serotonin and norepinephrine uptake inhibitor with antidepressant and anxiolytic properties.

RATIONALE: Serotonin (5-HT) and norepinephrine (NE) re-uptake inhibitors (SNRIs) have been proposed to have a higher efficacy and/or faster onset of action than previously available antidepressants. OBJECTIVES: We examined in biochemical, electrophysiological and behavioural assays the antidepressant properties of (S)-(-)-4-[(3-fluorophenoxy)-phenyl]methyl-piperidine (F-98214-TA), a compound that displays very high affinity for 5-HT and NE transporters. RESULTS: F-98214-TA potently inhibited the uptake of both 5-HT and NE into rat brain synaptosomes (IC50 = 1.9 and 11.2 nM, respectively) and decreased the electrical activity of dorsal raphe serotonergic neurones (ED50 = 530.3 microg/kg i.v.), an effect completely abolished by the 5-HT(1A) antagonist WAY100,635. In acute behavioural assays in mice, the orally administered compound potentiated the 5-hydroxy-tryptophan (5-HTP)-induced syndrome [minimal effective dose (MED) = 10 mg/kg], antagonized the hypothermia induced by a high dose of apomorphine (ED50 = 2 mg/kg) and reduced the immobility in the tail suspension test (MED = 10 mg/kg). Moreover, it also decreased the immobility in the forced swimming test in mice and rats (30 mg/kg, p.o.). Chronic administration of F-98214-TA (14 days, 30 mg kg(-1) day(-1), p.o.) attenuated the hyperactivity induced by olfactory bulbectomy in rats, confirming its antidepressant-like properties. Interestingly, the same dosage regimen significantly increased the social interaction time in rats, suggesting an additional potential anxiolytic activity. In most assays the compound was more potent than fluoxetine, venlafaxine and desipramine. CONCLUSIONS: F-98214-TA is a novel SNRI that displays greater potency than other reference antidepressants in animal models predictive of antidepressant and anxiolytic activities.

Syntheses and binding studies of new [(aryl)(aryloxy)methyl]piperidine derivatives and related compounds as potential antidepressant drugs with high affinity for serotonin (5-HT) and norepinephrine (NE) transporters.

In a wide search program toward new, efficient, and fast-acting antidepressant drugs, we have prepared series of new compounds having an (aryl)(aryloxy)methyl moiety linked directly or through a methylene chain to different substituted and unsubstituted cycles (isoquinoline, piperazine, piperidine, tetrahydropyran, or cyclopentane). These compounds have been evaluated for their affinities for serotonin (5-HT) transporter (SERT) and 5-HT(1A) and 5-HT(2A) receptors. Racemic mixtures of 4-[(aryl)(aryloxy)methyl]piperidine derivatives showed much higher affinity values for SERT than fluoxetine and resulted in lack of affinity for 5-HT(1A) and 5-HT(2A) receptors. Some of these racemic mixtures were resolved to their enantiomers and tested for binding to norepinephrine (NE) transporter (NET), dopamine (DA) transporter (DAT), and alpha(2) receptor. Several of these enantiomers [(-)-15b, (-)-15j, (-)-15t, (+)-15u] displayed a dual binding profile with affinities for SERT and NET with K(i) < 25 nM and a NET/SERT ratio <10. Compound (-)-15j (coded as F-98214-TA for development studies) showed a dual binding profile with very high affinity values for SERT and NET (K(i) = 1.9 and 13.5 nM, respectively), and further pharmacological characterization is in progress for its evaluation as a antidepressant.

A new flavonoid derivative, dosmalfate, attenuates the development of dextran sulphate sodium-induced colitis in mice.

In this study, we have evaluated the efficacy of dosmalfate, a new flavonoid derivative compound, for the prevention and treatment of experimental colitis. To induce colitis, BALB/c mice received 5% dextran sulphate sodium (DSS) in their drinking water continuously for 7 days. Colitis was quantified by a clinical damage score, colon length, weight loss, stool consistency and rectal bleeding. Inflammatory response was assessed by neutrophil infiltration, determined by histology and myeloperoxidase (MPO) activity. Interleukin (IL)-1 beta, prostaglandins (PG)E(2) and (PG)D(2) concentrations in colonic tissue, histological and histochemical analysis of the lesions were also measured. Dosmalfate (400-800 mg/kg body weight, p.o.) ameliorated severe colitis reduced the degree of inflammation through reduction of neutrophil infiltration and IL-1 beta levels. (PG)E(2) and (PG)D(2) synthesis were significantly reduced in colitis control group and treatment with dosmalfate abolished the decrease in PG synthesis in colon mucosa. We conclude that dosmalfate is protective in acute DSS-induced colitis. The beneficial effects seem to be related to a decrease of neutrophil infiltration, absence of up-regulation of IL-1 beta and increase of PG production in colon mucosa.

Synthesis and pharmacological characterization of a new benzoxazole derivative as a potent 5-HT3 receptor agonist.

N-(2-Benzoxazol-2-yl-ethyl)-guanidine hydrochloride (10) was synthesized and pharmacologically tested. This compound showed high affinity for the 5-HT(3) receptor (K(i)=0.77 nM) and potently triggered the von Bezold-Jarisch reflex (BJR) in rats with an ED(50)=0.52 microg/kg iv and intrinsic activity next to 1 (i.a.=0.94). This stimulant effect was abolished by pretreatment with the 5-HT(3) receptor antagonist granisetron and was subject to a rapid and pronounced tachyphylaxis, due to desensitization of the peripheric cardiac 5-HT(3) receptor. Consequently, 10 acts as an in vivo 5-HT(3) antagonist inhibiting the BJR responses evoked by submaximal doses of 5-HT with an ID(50)=5.8 microg/kg iv.

Effects of dosmalfate, a new cytoprotective agent, on acute and chronic trinitrobenzene sulphonic acid-induced colitis in rats.

Activated neutrophils and proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) are clearly involved in the pathogenesis of bowel disease. Increased expression of epidermal growth factor-receptor (EGF receptor) has been reported for the colon mucosa surrounding areas of ulceration, suggesting a pivotal role in mucosal defence and repair. In this study, we examined the effects of dosmalfate, a new flavonoid derivative compound (diosmin heptakis) with antioxidant and cytoprotective properties, on acute and chronic experimental trinitrobenzene sulphonic acid (TNBS)-induced colitis in rats. The inflammation response was assessed by neutrophil infiltration as evaluated by histology and myeloperoxidase activity. Mucosal TNF-alpha production and histological analysis of the lesions was also carried out. In addition, we studied the expression of the EGF receptor inmunohistochemically during the healing of TNBS-induced chronic colitis. A 2-day treatment with 400 or 800 mg/kg of dosmalfate ameliorated the colon damage score and the incidence of adhesions. It also significantly (P<0.05) decreased myeloperoxidase activity and colonic mucosal production of TNF-alpha. Chronic treatment (14 days) with 800 mg/kg/day of dosmalfate also had significant protective effects on TNBS-induced colitis which were reflected by significant attenuation (P<0.05) of the damage score while the inflammatory indicators were not improved. The chronic beneficial effect of dosmalfate was apparently related to the enhancement of EGF receptor expression. These findings confirm the protective effects of dosmalfate in acute and chronic experimental colitis.

New 3-benzisothiazolyl and 3-benzisoxazolylpiperazine derivatives with atypical antipsychotic binding profile.

New 3-benzisothiazolyl and 3-benzisoxazolylpiperazine derivatives were synthesised and their 5-HT(1A), 5-HT(2A) and D(2) receptor binding affinities evaluated. The compounds displayed high affinity for the 5-HT(2A) receptor combined with moderate to low 5-HT(1A) and D(2) affinities. Two of them, 18 and 25, have been selected for further pharmacological studies to be evaluated as potential atypical antipsychotics.

Synthesis and pharmacology of isoquinuclidine derivatives as 5-HT(3) ligands.

A series of 4-amino-5-chloro-2-methoxybenzoates and benzamides containing the 5- and 6-isoquinuclidinyl system was synthesised and evaluated for binding to 5-HT(3), 5-HT(4) and D(2) receptors. In general, the isoquinuclidine derivatives at the 5-position have shown to be more potent as 5-HT(3) ligands but they also possess 5-HT(4) and D(2) properties. However, the results show that the derivatives at the 6-position afforded the most promising compounds in terms of both receptor affinity and selectivity.