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1.
Pharmacol Res ; 78: 1-9, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24083950

ABSTRACT

Selective cyclooxygenase 2 (COX2) inhibitors (COXIBs) are effective anti-inflammatory and analgesic drugs with improved gastrointestinal (GI) safety compared to nonselective nonsteroidal anti-inflammatory drugs known as traditional (tNSAIDs). However, their use is associated with a cardiovascular (CV) hazard (i.e. increased incidence of thrombotic events and hypertension) due to the inhibition of COX2-dependent vascular prostacyclin. Aiming to design COX2-selective inhibitors with improved CV safety, new NO-releasing COXIBs (NO-COXIBs) have been developed. In these hybrid drugs, the NO-mediated CV effects are expected to compensate for the COXIB-mediated inhibition of prostacyclin. This study evaluates the potential CV beneficial effects of VA694, a promising NO-COXIB, the anti-inflammatory effects of which have been previously characterized in several in vitro and in vivo experimental models. When incubated in hepatic homogenate, VA694 acted as a slow NO-donor. Moreover, it caused NO-mediated relaxant effects in the vascular smooth muscle. The chronic oral administration of VA694 to young spontaneously hypertensive rats (SHRs) significantly slowed down the age-related development of hypertension and was associated with increased plasma levels of nitrates, stable end-metabolites of NO. Furthermore, a significant improvement of coronary flow and a significant reduction of endothelial dysfunction were observed in SHRs submitted to chronic administration of VA694. In conclusion, VA694 is a promising COX2-inhibiting hybrid drug, showing NO releasing properties which may mitigate the CV deleterious effects associated with the COX2-inhibition.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Cyclooxygenase 2 Inhibitors/pharmacology , Endothelium-Dependent Relaxing Factors/administration & dosage , Endothelium/drug effects , Hypertension/drug therapy , Nitrates/pharmacology , Nitric Oxide/administration & dosage , Pyrroles/pharmacology , Animals , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Blood Pressure/drug effects , Coronary Vessels/drug effects , Cyclooxygenase 2 Inhibitors/chemistry , Endothelium/pathology , Endothelium-Dependent Relaxing Factors/pharmacology , Hypertension/blood , Male , Nitrates/blood , Nitrates/chemistry , Nitric Oxide/pharmacology , Nitrites/blood , Pyrroles/chemistry , Rats , Rats, Inbred SHR , Rats, Wistar , Regional Blood Flow/drug effects
2.
Curr Med Chem ; 18(10): 1540-54, 2011.
Article in English | MEDLINE | ID: mdl-21428878

ABSTRACT

The development of the coxib family has represented a stimulating approach in the treatment of inflammatory disorders, such as arthritis, and for the management of acute pains, in relation to the well-known traditional Non-Steroidal Anti-inflammatory Drugs (t-NSAIDs). Prompted by the pursuit for new cyclooxygenase-2 (COX-2) inhibitors, endowed with fine tuned selectivity and high potency, in the past years we have identified novel classes of ether, ester and acid molecules characterized by the 1,5-diarylpyrrole scaffold as potentially powerful anti-inflammatory molecules (12-66). All compounds proved to exert an in vitro inhibition profile as good as that shown by reference compounds. Compounds bearing a p-methylsulfonylphenyl substituent at C5 displayed the best issues. In particular, ester derivatives proved to perform the best in vitro profile in terms of selectivity and activity toward COX-2. The cell-based assay data showed that an increase of hindrance at the C3 side chain of compounds could translate to activity enhancement. The human whole blood (HWB) test let to highlight that submitted compounds displayed 5-10 fold higher selectivity for COX-2 vs COX-1 which should translate clinically to an acceptable gastrointestinal safety and mitigate the cardiovascular effects highlighted by highly selective COX-2 inhibitors. Finally, to assess in vivo anti-inflammatory and analgesic activity three different tests (rat paw pressure, rat paw oedema and abdominal constriction) were performed. Results showed good in vivo anti-inflammatory and analgesic activities. The issues gained with these classes of compounds represent, nowadays, a potent stimulus for a further enlargement of the NSAIDs family. In this review we describe the results obtained by our research group on this topic.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Pyrroles/chemistry , Pyrroles/pharmacology , Analgesics/chemistry , Analgesics/pharmacology , Analgesics/therapeutic use , Animals , Anti-Inflammatory Agents/therapeutic use , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Cyclooxygenase 1/metabolism , Cyclooxygenase 2/metabolism , Cyclooxygenase Inhibitors/chemistry , Cyclooxygenase Inhibitors/pharmacology , Cyclooxygenase Inhibitors/therapeutic use , Humans , Pyrroles/therapeutic use , Structure-Activity Relationship
3.
J Pharm Biomed Anal ; 35(2): 321-9, 2004 Apr 16.
Article in English | MEDLINE | ID: mdl-15063465

ABSTRACT

A high-performance liquid chromatography (HPLC)-method after solid-phase extraction (SPE) has been developed in order to determine a new angiotensin-AT1 antagonist, i.e. CR 3210 (C27H24N8; MW = 460.54), 4-[4-[(2-ethyl-5,7-dimethylimidazo[4,5-b]pyridin-3-yl)methyl]phenyl]-3-(2H-tetrazol-5-yl)quinoline in rat plasma and urine after oral administration to Sprague-Dawley rats. CR 3210 and the internal standard (IS) CR 1505 (loxiglumide), i.e. 4-[(3,4-dichlorobenzoyl)amino]-5-[(3-methoxypropyl)pentylamino]-5-oxopentanoic acid, were isolated from rat urine and plasma by solid-phase extraction. The procedure was optimized regarding the sorbent extraction material, the pH in the conditioning solution, the washing step, the dry time and the type of elution solvent. The separation was performed by reversed-phase high-performance liquid chromatography with ultraviolet detection. The samples were injected onto the analytical column (Tracer Extrasil ODS1) and detected at 238 nm, giving a capacity factor of 1.87 for CR 3210 and 1.10 for the internal standard. The selectivity of the method was satisfactory. The mean recovery of CR 3210 from spiked rat plasma was 68.5 at 75 ng/ml and 80.9 at 3000 ng/ml; the mean recovery of CR 3210 from spiked rat urine was 69.9 at 75 ng/ml and 78.6 at 3000 ng/ml. The lower limit of detection (LOD) was 14 ng/ml in plasma and 22 ng/ml in urine samples. The lower limit of quantification (LOQ) was taken as 30 ng/ml, the lowest calibration standard using 500 microl rat plasma and urine. The procedures were validated according to international standards with a good reproducibility and linear response from 30 to 3000 ng/ml, for either plasma or urine. The sensitivity of the method allowed for its application to pharmacokinetic studies.


Subject(s)
Angiotensin II Type 1 Receptor Blockers/analysis , Proglumide/analogs & derivatives , Purines/analysis , Purines/pharmacology , Quinolines/analysis , Quinolines/pharmacology , Receptor, Angiotensin, Type 1/metabolism , Angiotensin II Type 1 Receptor Blockers/chemistry , Angiotensin II Type 1 Receptor Blockers/pharmacology , Animals , Chromatography, High Pressure Liquid/methods , Proglumide/analysis , Proglumide/chemistry , Proglumide/pharmacology , Purines/chemistry , Quinolines/chemistry , Rats , Rats, Sprague-Dawley , Sensitivity and Specificity
4.
Farmaco ; 58(9): 837-44, 2003 Sep.
Article in English | MEDLINE | ID: mdl-13679177

ABSTRACT

A simple and sensitive method for the determination of a new angiotensin-AT(1) antagonist i.e. CR 3210, 4-[4-[(2-ethyl-5,7-dimethylimidazo[4,5-b]pyridin-3-yl)methyl]phenyl]-3-(2H-tetrazol-5-yl)quinoline, is described. The assay was utilised to describe the pharmacokinetic profile of the title compound after intravenous and intraperitoneal administration to Sprague Dawley rats. CR 3210 and the internal standard CR 1505 (loxiglumide, 4-[(3,4-dichlorobenzoyl)amino-5-[(3-methoxypropyl)pentylamino]-5-oxopentanoic acid) were isolated from rat plasma by solid-phase extraction. The sorbent extraction material along with the pH in the conditioning solution and the washing volume were considered pivotal parameters for the optimisation of the procedure. The separations were performed by reversed-phase high-performance liquid chromatography with ultraviolet detection. The samples were injected onto the analytical column (Tracer Extrasil ODS1) and detected at 238 nm, giving a retention time of 6.19 min for CR 3210 and 4.39 min for the internal standard, respectively. The selectivity of the method showed to be satisfactory. The mean recovery of CR 3210 from spiked rat plasma was 80.3 at 1 microg/ml and 79.9 at 2 microg/ml. The lower limit of detection (LOD) was taken as 0.014 microg/ml in plasma samples. The lower limit of quantification (LOQ) was taken as 0.02 microg/ml, the lowest calibration standard using 500 microg rat plasma. The procedures were validated according to international standards with a good reproducibility and linear response from 0.02 to 2 microg/ml. The sensitivity of the method allowed for its application to pharmacokinetic studies. The maximal concentration was detected 5' after the IV administration, whereas no significant absorption was evident after IP administration of CR 3210 to Sprague-Dawley rats. Our study suggests the absence of extensive bio-transformation of the drug in vivo, supported by the evidence that no metabolites were detected in plasma samples.


Subject(s)
Angiotensin II Type 1 Receptor Blockers , Purines/pharmacokinetics , Quinolines/pharmacokinetics , Animals , Chromatography, High Pressure Liquid , Injections, Intraperitoneal , Injections, Intravenous , Purines/administration & dosage , Purines/blood , Quinolines/administration & dosage , Quinolines/blood , Rats , Rats, Sprague-Dawley , Sensitivity and Specificity , Time Factors
5.
Chirality ; 13(9): 606-12, 2001.
Article in English | MEDLINE | ID: mdl-11579457

ABSTRACT

Compounds 2a and 3a-e are racemic 2-[(acylamino)ethyl]-1,4-benzodiazepines, tifluadom analogs, with high affinity and selectivity towards the kappa-opioid receptor. We describe the enantiomeric separation of all compounds through liquid chromatography with chiral stationary phases, as well as the resolution of the enantiomers of the most interesting compounds, 2a and 3a, by the semipreparative column Chiralpak AD. The configuration of the resolved enantiomers was investigated: the comparative study of CD and (1)H NMR spectra shows that compounds (-)-2a and (-)-3a have the same absolute configuration of (+)-(S)-tifluadom. A study on the stereoselective interaction with opiate receptors is reported.


Subject(s)
Benzodiazepinones/chemical synthesis , Receptors, Opioid, kappa/drug effects , Circular Dichroism , Humans , Magnetic Resonance Spectroscopy , Molecular Conformation , Receptors, Opioid, mu/chemistry , Receptors, Opioid, mu/drug effects , Receptors, sigma/chemistry , Receptors, sigma/drug effects , Recombinant Proteins/chemistry , Recombinant Proteins/drug effects , Stereoisomerism
6.
J Med Chem ; 44(8): 1134-50, 2001 Apr 12.
Article in English | MEDLINE | ID: mdl-11312914

ABSTRACT

The synthetic-computational approach to the study of the binding site of peripheral benzodiazepine receptor (PBR) ligands related to 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide (PK11195, 1) within their receptor (Cappelli et al. J. Med. Chem. 1997, 40, 2910-2921) has been extended. A series of carboxamide derivatives endowed with differently substituted planar aromatic or heteroaromatic systems was designed with the aim of getting further information on the topological requisites of the carbonyl and aromatic moieties for interaction with the PBR binding site. The synthesis of most of these compounds involves Weinreb amidation of the appropriate lactone as the key step. The most potent compound, among the newly synthesized ones, shows a nanomolar PBR affinity similar to that shown by 1 and the presence of a basic N-ethyl-N-benzylaminomethyl group in 3-position of the quinoline nucleus. Thus, it may be considered the first example of a new class of water soluble derivatives of 1. Several computational methods were used to furnish descriptors of the isolated ligands (indirect approaches) able to rationalize the variation in the binding affinity of the enlarged series of compounds. Sound QSAR models are obtained by size and shape descriptors (volume approach) which codify for the short-range contributions to ligand-receptor interactions. Molecular descriptors which explicitly account for the electrostatic contribution to the interaction (CoMFA, CoMSIA, and surface approaches) perform well, but they do not improve the quantitative models. Moreover, useful hints for the identification of the antagonist binding site in the three-dimensional modeling of the receptor (direct approach) were provided by the receptor hypothesis derived by the pharmacophoric approach. The ligand-receptor complexes obtained provided a detailed description of the modalities of the interaction and interesting suggestions for further experiments.


Subject(s)
Quinolines/chemical synthesis , Receptors, GABA-A/chemistry , Amino Acid Sequence , Animals , Binding, Competitive , Cerebral Cortex/metabolism , In Vitro Techniques , Isoquinolines/chemistry , Isoquinolines/metabolism , Ligands , Male , Models, Molecular , Molecular Conformation , Molecular Sequence Data , Quantitative Structure-Activity Relationship , Quinolines/chemistry , Quinolines/metabolism , Radioligand Assay , Rats , Receptors, GABA-A/metabolism , Sequence Alignment
7.
J Med Chem ; 44(4): 579-85, 2001 Feb 15.
Article in English | MEDLINE | ID: mdl-11170647

ABSTRACT

The novel quinoline-2-carboxamide derivatives N-[methyl-11C]-3-methyl-4-phenyl-N-(phenylmethyl)quinoline-2-carboxamide ([11C]4), (+/-)-N-[methyl-11C]-3-methyl-N-(1-methylpropyl)-4-phenylquinoline-2-carboxamide ([11C]5), and (+/-)-N-[methyl-11C]-3-methyl-4-(2-fluorophenyl)-N-(1-methylpropyl)quinoline-2-carboxamide ([11C]6) were labeled with carbon-11 (t1/2 = 20.4 min, beta+ = 99.8%) as potential radioligands for the noninvasive assessment of peripheral benzodiazepine type receptors (PBR) in vivo with positron emission tomography (PET). The radiosynthesis consisted of N-methylation of the desmethyl precursors 3-methyl-4-phenyl-N-(phenylmethyl)quinoline-2-carboxamide (4a), (+/-)-3-methyl-N-(1-methylpropyl)-4-phenylquinoline-2-carboxamide (5a), and (+/-)-4-(2-fluorophenyl)-3-methyl-N-(1-methylpropyl)quinoline-2-carboxamide (6a) with either [11C]methyl iodide or [11C]methyl triflate in the presence of tetrabutylammonium hydroxide or potassium hydroxide in dimethylformamide. The radioligands [11C]4, [11C]5, and [11C]6 were synthesized with over 99% radiochemical purity in 30 min, 30 +/- 5% radiochemical yield, calculated at the end of synthesis (EOS) non-decay-corrected, and 2.5 +/- 1.2 Ci/micromol of specific radioactivity. Inhibition studies in rats following intravenous pre-administration of 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide (PK 11195, 1) showed high specific binding to PBR of [11C]4, [11C]5, and [11C]6 in heart, lung, kidney, adrenal gland, spleen, and brain. The biological data suggest that [11C]5, [11C]6, and particularly [11C]4 are promising radioligands for PBR imaging in vivo with PET.


Subject(s)
Amides/chemical synthesis , Quinolines/chemical synthesis , Radiopharmaceuticals/chemical synthesis , Receptors, GABA-A/metabolism , Amides/chemistry , Amides/metabolism , Animals , Carbon Radioisotopes , Isotope Labeling , Ligands , Male , Methylation , Quinolines/chemistry , Quinolines/metabolism , Radiopharmaceuticals/chemistry , Radiopharmaceuticals/metabolism , Rats , Tissue Distribution , Tomography, Emission-Computed
8.
J Med Chem ; 42(9): 1556-75, 1999 May 06.
Article in English | MEDLINE | ID: mdl-10229626

ABSTRACT

Novel 5-HT3 receptor ligands were designed and synthesized with the aim of obtaining deeper insight into the molecular basis of the intrinsic efficacy of arylpiperazines interacting with the central 5-HT3 receptor. The newly synthesized compounds and some previously published compounds belonging to the same class of heteroarylpiperazines were tested for their potential ability to displace [3H]granisetron from rat cortical membranes. These 5-HT3 receptor binding studies revealed subnanomolar affinity in several of the compounds under study. The most active ligands were quipazine derivatives bearing a phenyl group in the 4-position and various oxygenated alkyl side chains in the 3-position of the quinoline nucleus. Qualitative and theoretical quantitative structure-affinity relationship studies were carried out, and the interaction model for the 5-HT3 ligands related to quipazine with their receptor, proposed in part 1 of the present work, was updated to incorporate the latest data. The potential 5-HT3 agonist/antagonist activity of 12 selected compounds was assessed in vitro on the 5-HT3 receptor-dependent [14C]guanidinium uptake in NG 108-15 cells. Their intrinsic efficacy ranged from the 5-HT3 full agonist properties of compounds 7a and 8h, i to those of partial agonists 10a,d and antagonists 8b,d,e, and 9c, d,h,i. The comparison between these functional data and those relative to the previously described compounds suggested that in this class of 5-HT3 ligands the intrinsic efficacy is modulated in a rather subtle manner by the steric features of the heteroaryl moiety.


Subject(s)
Piperazines/chemical synthesis , Receptors, Serotonin/drug effects , Serotonin Antagonists/chemical synthesis , Serotonin Receptor Agonists/chemical synthesis , Animals , Binding, Competitive , Brain/metabolism , Cell Line , Granisetron/metabolism , In Vitro Techniques , Ligands , Male , Mice , Models, Molecular , Piperazines/chemistry , Piperazines/metabolism , Piperazines/pharmacology , Rats , Rats, Wistar , Receptors, Serotonin/metabolism , Receptors, Serotonin, 5-HT3 , Serotonin Antagonists/chemistry , Serotonin Antagonists/metabolism , Serotonin Antagonists/pharmacology , Serotonin Receptor Agonists/chemistry , Serotonin Receptor Agonists/metabolism , Serotonin Receptor Agonists/pharmacology , Structure-Activity Relationship
9.
J Med Chem ; 41(5): 728-41, 1998 Feb 26.
Article in English | MEDLINE | ID: mdl-9513601

ABSTRACT

Synthesis and pharmacological evaluation of a series of condensed quinoline and pyridine derivatives bearing a N-methylpiperazine moiety attached to the 2-position of the quinoline or pyridine nucleus are described. 5-HT receptor binding studies revealed subnanomolar affinity for the 5-HT3 receptor subtype in some of the compounds under study. The most active compound (5b) displayed a Ki value about 1 order of magnitude higher than that of quipazine along with a higher selectivity. The potential 5-HT3 agonist/antagonist activity of four selected compounds was assessed in vitro on 5-HT3 receptor-dependent [14C]guanidinium uptake in NG 108-15 cells. Compound 5j acted as a 5-HT3 agonist in this assay with an EC50 value close to that reported for quipazine, while 5b was a partial agonist with an EC50 value of about 0.25 nM, and compound 5c possessed antagonist properties with an IC50 value (approximately 8 nM) in the same range as those of previously characterized 5-HT3 receptor antagonists. Qualitative and quantitative structure-affinity relationship studies carried out by making use of theoretical molecular descriptors allowed to elucidate the role of the main pharmacophoric components and to develop a model for the interaction of the 5-HT3 ligands related to quipazine with their receptor.


Subject(s)
Phenanthridines/metabolism , Piperazines/metabolism , Receptors, Serotonin/chemistry , Receptors, Serotonin/metabolism , Serotonin Antagonists/metabolism , Serotonin Receptor Agonists/metabolism , Animals , Benzene/chemistry , Binding Sites , Glioma , Guanidine/metabolism , Mice , Models, Molecular , Molecular Structure , Neuroblastoma , Phenanthridines/chemical synthesis , Phenanthridines/pharmacology , Piperazines/chemical synthesis , Piperazines/pharmacology , Quinolines/chemistry , Quipazine/chemistry , Quipazine/metabolism , Rats , Receptors, Serotonin/drug effects , Receptors, Serotonin, 5-HT3 , Serotonin Antagonists/chemical synthesis , Serotonin Receptor Agonists/chemical synthesis , Structure-Activity Relationship , Tumor Cells, Cultured
10.
J Med Chem ; 40(22): 3670-8, 1997 Oct 24.
Article in English | MEDLINE | ID: mdl-9357534

ABSTRACT

The synthesis and the biological evaluation of a series of novel pyrroloquinoxaline derivatives are described. In binding studies several compounds proved to be potent and selective 5-HT3 receptor ligands. The most active pyrroloquinoxalines, 11d and 11e, showed a subnanomolar affinity for 5-HT3 receptor and were able to functionally discriminate the central and peripheral 5-HT3 receptor, being agonists and antagonists, respectively. In functional studies ([14C]-guanidinium accumulation test in NG 108-15 cells, in vitro) most of the synthesized compounds showed clear-cut 5-HT3 agonist properties. In in vivo studies on the von Bezold-Jarisch reflex test (a peripheral interaction model) the behavior of the tested compounds ranged from agonist to antagonist, while clear agonist properties were obtained with 12a on cortical acetylcholine release in freely moving rats. Pharmacokinetic studies with 11e and 12c indicate that the compounds easily cross the blood-brain barrier (BBB) after systemic administration with a brain/plasma ratio of 17.5 and 37.5, respectively. Thus compounds 11e and 12c represent the most potent central 5-HT3 agonists identified to date that are able to cross the blood-brain barrier.


Subject(s)
Quinoxalines/pharmacology , Receptors, Serotonin/drug effects , Serotonin Receptor Agonists/pharmacology , Animals , Blood-Brain Barrier , Cell Line , Cerebral Cortex/drug effects , Cerebral Cortex/metabolism , Hybrid Cells , Magnetic Resonance Spectroscopy , Male , Mice , Quinoxalines/chemistry , Quinoxalines/pharmacokinetics , Rats , Rats, Sprague-Dawley , Receptors, Serotonin, 5-HT3 , Reflex/drug effects , Serotonin Receptor Agonists/chemistry , Serotonin Receptor Agonists/pharmacokinetics , Spectrophotometry, Infrared , Structure-Activity Relationship
11.
J Med Chem ; 40(18): 2910-21, 1997 Aug 29.
Article in English | MEDLINE | ID: mdl-9288173

ABSTRACT

A synthetic-computational approach to the study of the binding site of peripheral benzodiazepine receptor (PBR) ligands related to 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxam ide (PK11195, 1) within their receptor has been developed. A wide series of conformationally restrained derivatives of 1 has been designed with the aim of probing the PBR binding site systematically. The synthesis of these compounds involves palladium-catalyzed coupling and amidation as the key steps. Twenty-nine rigid and semirigid derivatives of 1 were tested in binding studies using [3H]-1, and most of these showed PBR affinities in the nanomolar range. The essential role of the carbonyl moiety as a primary pharmacophoric element in the recognition by and the binding to PBR has been confirmed, and the restricted range of the carbonyl orientations, which characterizes the most potent ligands, points to a specific hydrogen-bonding interaction, mainly directed by the geometrical factors, when the electronic ones are fulfilled. Moreover, the fundamental importance of the short-range dispersive interactions in the modulation of the binding affinity and, hence, in the stabilization of the ligand-receptor complex, emerged from the QSAR models reported.


Subject(s)
Brain/metabolism , Isoquinolines/metabolism , Receptors, GABA-A/chemistry , Receptors, GABA-A/metabolism , Animals , Binding Sites , Calorimetry , Indicators and Reagents , Isoquinolines/chemical synthesis , Isoquinolines/chemistry , Kinetics , Magnetic Resonance Spectroscopy , Male , Mass Spectrometry , Molecular Conformation , Molecular Structure , Organ Specificity , Radioligand Assay , Rats , Rats, Inbred Strains , Structure-Activity Relationship , Tritium
12.
J Med Chem ; 39(21): 4275-84, 1996 Oct 11.
Article in English | MEDLINE | ID: mdl-8863805

ABSTRACT

Alpidem (1), the anxiolytic imidazopyridine, has nanomolar binding affinity for both the central benzodiazepine receptor (CBR) and the peripheral benzodiazepine receptor (PBR). A novel class of PBR ligands related to alpidem has been designed by comparing the interaction models of alpidem with PBR and CBR. Several compounds in this class have shown high selectivity for PBR vs CBR, and the selectivity has been discussed in terms of interaction models. The binding behavior of the three selected compounds was extensively studied by competition and saturation assays, and the results suggest that they are capable of recognizing two sites labeled by [3H]PK11195. The molecular structure of one of the most active compounds (4e) has been determined by X-ray diffraction and compared with that of alpidem. Molecular modeling studies suggest that the bioactive conformation of 4e is likely to be very similar to the conformation found in the crystal.


Subject(s)
Anti-Anxiety Agents/chemistry , Imidazoles/chemistry , Pyridines/chemistry , Receptors, GABA-A/metabolism , Animals , Anti-Anxiety Agents/metabolism , Binding, Competitive , Cerebral Cortex/metabolism , Drug Design , Flunitrazepam/metabolism , Imidazoles/metabolism , Isoquinolines/metabolism , Models, Molecular , Protein Conformation , Pyridines/metabolism , Rats , Structure-Activity Relationship
13.
Bioorg Med Chem ; 4(8): 1255-69, 1996 Aug.
Article in English | MEDLINE | ID: mdl-8879547

ABSTRACT

The molecular structure and the dynamic behaviour of some potent 5-HT3 antagonists structurally related to quipazine have been investigated by NMR spectroscopy and by computational methods in order to gain insight into the structure-activity relationships at a molecular level. The role of the different dynamic behaviour of these compounds in the binding to 5-HT3 receptors is discussed. A model of ligand-receptor interaction has been developed on the basis of molecular orbital calculations and on the reference ligands quipazine, ondansetron and LY278584. The interaction model proposed herein rationalizes the observed agonist-antagonist shift between quipazine and investigated compounds with the assumption of different but overlapping binding domains for antagonists and agonists at the 5-HT3 receptor.


Subject(s)
Receptors, Serotonin/metabolism , Serotonin Antagonists/chemistry , Affinity Labels/metabolism , Indazoles/metabolism , Lipid Metabolism , Magnetic Resonance Spectroscopy , Models, Molecular , Ondansetron/metabolism , Serotonin Antagonists/metabolism , Software , Structure-Activity Relationship , Temperature , Tropanes/metabolism
14.
J Med Chem ; 39(4): 860-72, 1996 Feb 16.
Article in English | MEDLINE | ID: mdl-8632410

ABSTRACT

The synthesis and biological evaluation of a series of 2-substituted 5-phenyl-1,4-benzodiazepines, structurally related to tifluadom (5), the only benzodiazepine that acts simultaneously as a kappa-opioid agonist and a cholecystokinin-A (CCK-A) antagonist, are reported. The radioligand binding models used in these studies were [(125)I](BH)-CCK-8 in rat pancreas (CCK-A), [(3)H]-(MENLE(28,31))-cck-8 in guinea pig cerebral cortex (CCK-B), and [(3)H]U-69593 (kappa(1)), [(3)H]DAMGO (mu), and [(3)H]DADLE (delta) in guinea pig brain. All the title compounds were devoid of significant affinity for both CCK-A and CCK-B receptors, while some of them bound with nanomolar affinity and high selectivity for kappa-opioid receptors. In particular, the 2-thienyl derivative 7A(X = H) with a K(i) = 0.50 nM represents a clear improvement with respect to tifluadom, showing a comparable potency but higher selectivity. The application of computational simulations and linear regression analysis techniques to the complexes between guinea pig kappa (kappa(1))-receptor and the title compounds allowed the identification of the structural determinants for recognition and quantitative elucidation of the structure-affinity relationships in this class of receptors.


Subject(s)
Benzodiazepines/chemistry , Benzodiazepines/chemical synthesis , Receptors, Cholecystokinin/metabolism , Receptors, Opioid, kappa/agonists , Receptors, Opioid, kappa/metabolism , Amino Acid Sequence , Analgesics/metabolism , Animals , Benzodiazepines/metabolism , Binding, Competitive , Brain/metabolism , Cerebral Cortex/metabolism , Computer Graphics , Conserved Sequence , Enkephalin, Ala(2)-MePhe(4)-Gly(5)- , Enkephalin, Leucine-2-Alanine/metabolism , Enkephalins/metabolism , Guinea Pigs , Humans , Ligands , Mice , Models, Molecular , Molecular Sequence Data , Molecular Structure , Pancreas/metabolism , Protein Conformation , Radioligand Assay , Rats , Receptors, Cholecystokinin/chemistry , Sequence Homology, Amino Acid , Sincalide/metabolism , Structure-Activity Relationship
15.
J Am Soc Mass Spectrom ; 7(7): 653-63, 1996 Jul.
Article in English | MEDLINE | ID: mdl-24203480

ABSTRACT

Pyrrolo[1,2-a][1,4]benzodiazepin-4-one (1), -6-one (2), and -4,6-dione (3), which are starting materials for the synthesis of pharmacologically interesting compounds that are active as neurotropic agents, have been characterized in the gas phase. The application of different mass spectrometric techniques, such as electron ionization, high-resolution, and tandem mass spectrometry, has allowed the structural characterization and differentiation of their molecular ions and most abundant fragment ions formed in the source. In particular, the two positional isomers 1 and 2 produce quite different mass spectra, and their molecular and the most intense fragment ions yield different metastable mass-analyzed ion kinetic energy spectra. Furthermore, high-resolution mass spectrometry and accurate mass measurements have revealed different elemental compositions and abundances for isobaric fragment ions produced by isomers 1 and 2. From these data and from the comparison with those relevant to compound 3, it has been possible to evaluate the influence of the position of the carbonyl group on the fragmentation pathways.Semiempirical molecular orbital calculations carried out by both the modified neglect of differential overlap and Austin 1 methods have provided useful information on the characterization of the neutrals as well as the molecular ions of compounds 1-3.

16.
J Med Chem ; 38(14): 2692-704, 1995 Jul 07.
Article in English | MEDLINE | ID: mdl-7629808

ABSTRACT

Synthesis and pharmacological evaluation of a series of condensed quinoline derivatives bearing a basic nitrogen on piperazine or [(dimethylamino)ethyl]thio moieties attached at the 2-position of the quinoline nucleus are described. 5-HT receptor binding studies revealed, for most of the compounds studied, nanomolar affinity for the 5-HT3 receptor subtype. The most active compound, benzopyrano[3,4-c]quinoline derivative 5f, displayed a Ki value very similar to that reported for quipazine along with an improved selectivity. Functional and in vivo testing carried out on three selected compounds showed that 5f,j,n are potent 5-HT3 receptor antagonists with potencies in the same range as the best known 5-HT3 receptor antagonists ondansetron, tropisetron, and zacopride. The crystal and molecular structures of compounds 5f,j,n were determined by single-crystal X-ray diffraction and used as starting structures for molecular modeling studies. Comparative molecular field analysis (CoMFA) was applied to binding constants of compounds 5a-p and 6a-h. The cross-validated r2, derived from partial least-squares calculations, indicated a good predictive capacity for affinity values in the series of compounds investigated. Evidence for the prediction capacity is provided in the form of plots of actual vs predicted pKi values. The steric and electrostatic features of the CoMFA-derived model are presented as standard coefficient contour maps of steric and electrostatic fields.


Subject(s)
Piperazines/chemistry , Serotonin Antagonists/chemical synthesis , Animals , Crystallography, X-Ray , Guinea Pigs , In Vitro Techniques , Magnetic Resonance Spectroscopy , Male , Rats , Rats, Sprague-Dawley , Serotonin Antagonists/chemistry , Serotonin Antagonists/pharmacology , Structure-Activity Relationship , Tumor Cells, Cultured
17.
Farmaco ; 48(7): 897-905, 1993 Jul.
Article in English | MEDLINE | ID: mdl-8104405

ABSTRACT

The synthesis of 7-chloro-2,3-dihydro-2-(2-methoxyethyl)-1-methyl-5-phenyl- 1H-1,4-benzodiazepine (2) is described. While the metaclazepam-like compound 2 showed an affinity for benzodiazepine receptor central type (CBZRs) comparable to that of metaclazepam (1a), its intermediates bearing the exocyclic double bond resulted more active.


Subject(s)
Anti-Anxiety Agents/chemical synthesis , Benzodiazepines/chemical synthesis , Benzodiazepines/pharmacology , Receptors, GABA-A/metabolism , Animals , Anti-Anxiety Agents/metabolism , Anti-Anxiety Agents/pharmacology , Benzodiazepines/metabolism , Brain Chemistry/drug effects , In Vitro Techniques , Rats , Receptors, GABA-A/drug effects , Structure-Activity Relationship
18.
Farmaco ; 47(2): 191-202, 1992 Feb.
Article in English | MEDLINE | ID: mdl-1324688

ABSTRACT

A series of 2,3-dihydro-9-phenyl-1H-pyrrolo[3,4-b]quinolin-1-one derivatives and related compounds were tested for their ability to bind benzodiazepine receptors (BZRs). Most of the synthesized compounds showed micromolar affinity for BZR peripheral type, but not for the central one, with the exception of compound 4m which displayed an IC50 = 0.407 microM, only 2 fold higher than IC50 for chlordiazepoxide.


Subject(s)
Pyrroles/chemical synthesis , Quinolones/chemical synthesis , Receptors, GABA-A/drug effects , Animals , Brain Chemistry/drug effects , In Vitro Techniques , Mice , Mice, Inbred Strains , Pyrroles/pharmacology , Quinolones/pharmacology , Rats
19.
Ital J Orthop Traumatol ; 18(3): 287-95, 1992.
Article in English | MEDLINE | ID: mdl-1308873

ABSTRACT

The Porous Coated total hip Arthroplasty (PCA), used by the authors since August 1984, represents a considerable advancement in the field of prosthetic replacement. Its original design and biological fixation give it long-lasting stability not only in young patients, but also patients with initial osteoporosis. Its use in cases of advanced osteoporosis, however, is more controversial. The 8-year results are quite satisfactory from both a clinical and radiographic standpoint, confirming, as other authors have reported, that the medium and long-term results of cementless total hip replacement tend to stabilize because there is a lack of late reactions, which are more common in cemented implants.


Subject(s)
Hip Prosthesis , Adult , Aged , Aged, 80 and over , Cementation , Female , Follow-Up Studies , Hip Joint/diagnostic imaging , Hip Prosthesis/adverse effects , Humans , Male , Middle Aged , Prosthesis Design , Radiography
20.
Farmaco ; 46(12): 1435-47, 1991 Dec.
Article in English | MEDLINE | ID: mdl-1668253

ABSTRACT

The syntheses of some 3-substituted-2-(4-methyl-1-piperazinyl)-4-phenylquinolines are reported. The title compounds were tested for their potential activities on 5-HT receptor subtypes and 5-HT uptake site; compounds 4b-d showed micromolar affinity for 5-HT3 and 5-HT uptake site.


Subject(s)
Piperazines/chemical synthesis , Quinolones/chemical synthesis , Quipazine/analogs & derivatives , Serotonin Antagonists , Serotonin/metabolism , Animals , Binding, Competitive/drug effects , In Vitro Techniques , Ligands , Male , Paroxetine , Piperazines/pharmacology , Piperidines/metabolism , Quinolones/pharmacology , Quipazine/chemical synthesis , Quipazine/pharmacology , Rats , Rats, Inbred Strains
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