- HELICOBACTER PYLORI ERADICATING AGENT HAVING INHIBITORY ACTIVITY ON GASTRIC ACID SECRETION
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Disclosed are: a compound which is stable in an acid, has an antibacterial effect against a bacterium Helicobacter pylori, can exert a satisfactory level of an antibacterial effect when used singly, does not affect an enteric bacterium, has an antibacterial effect against a bacterium resistant to an antibacterial agent, and has an inhibitory effect on gastric acid secretion; and a pharmaceutical composition comprising the compound. Specifically disclosed are: a compound represented by the general formula (I) or a salt thereof; and a pharmaceutical composition comprising the compound or the salt thereof: wherein R represents a linear alkyl group having 4 to 8 carbon atoms, preferably 5 to 7 carbon atoms.
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Page/Page column 10
(2009/10/01)
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- Identification and synthesis of potential impurities of rabeprazole sodium
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Rabeprazole sodium (1, Achiphex) is a gastric proton pump inhibitor. It causes dose-dependent inhibition of acid secretion and is useful as an anti-ulcer agent. In the process for the preparation of 1, two potential unknown impurities were identified in HPLC at levels ranging from 0.05-0.8%. Based on mass spectral data vide LC-MS, the two impurities were characterized as 2-{[(4-chloro-3-methyl-2-pyridinyl) methyl] sulfinyl}-1H-bezimidazole (2, chloro analogue of rabeprazole) and 2-[{(4-methoxy-3-methyl-2-pyridinyl)methyl} sulfinyl]-1H-benzimidazole (3, methoxy analogue of rabeprazole). The structures were unambiguously established by independently synthesizing them and co-injecting in HPLC. To our knowledge, the compounds 2 and 3 have not been reported as process impurities elsewhere.
- Pingili, R. Reddy,Jambula, M. Reddy,Ganta, M. Reddy,Ghanta, M. Reddy,Sajja,Sundaram,Boluggdu, V. Bhaskar
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p. 814 - 818
(2007/10/03)
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- Structure-activity relationship of 2-[[(2-Pyridyl)methyl]thio]-1H- benzimidazoles as anti Helicobacter pylori agents in vitro and evaluation of their in vivo efficacy
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A relationship between the structure of 21 2-[[(2-pyridyl)methyl]thio]- 1H-benzimidazoles (6) and their anti Helicobacter pylori activity expressed as minimum bactericidal concentration (MBC) values is described. Observed MBCs ranged from 256 to 1 μg/mL. The structure - activity relationship (SAR) showed that larger and more lipophilic compounds, especially compounds with such substituents in the 4-position of the pyridyl moiety, generally had lower MBC values. Four new compounds 'that were predicted to be potent by the established SAR model were synthesized and tested. One such compound, i.e., 2-[[(4-[(cyclopropylmethyl)oxy]3-methyl-2-pyridyl)methyl]thio]-1H- benzimidazole (18), was tested for in vivo efficacy in a mouse Helicobacter felis model (125 μmol/kg bid given orally for 4 days, n = 4). Unfortunately, antibacterial activity could not be clearly demonstrated in this model. Instead a potent acid secretion inhibition was observed. This finding was attributed to the methylthio compound being oxidized to the corresponding methyl sulfinyl derivative, i.e., a proton pump inhibitor, in vivo. Although the antibacterial activity had the potential of decreasing H. felis cell counts in vivo the proton pump inhibitory effect became dominant and actually promoted H. felis cell growth. Hence, we conclude that the antibacterial utility of the 2-[[(2-pyridyl)methyl]thio]1H-benzimidazoles (6) as a compound class is compromised by their propensity to become proton pump inhibitors upon metabolic oxidation in vivo.
- Kühler, Thomas C.,Swanson, Marianne,Shcherbuchin, Vladimir,Larsson, H?kan,Mellg?rd, Bj?rn,Sj?str?m, Jan-Eric
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p. 1777 - 1788
(2007/10/03)
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- Structure-activity relationship of omeprazole and analogues as Helicobacter pylori urease inhibitors
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Helicobacter pylori urease belongs to a family of highly conserved urea- hydrolyzing enzymes. A common feature of these enzymes is the presence of two Lewis acid nickel ions and a reactive cysteine residue in the active site. The H+/K+-ATPase inhibitor omeprazole is a prodrug of a sulfenamide which covalently modifies cysteine residues on the luminal side of the H+/K+- ATPase of gastric parietal cells. Omeprazole and eight analogues were selected based on their chemical, electronic, and kinetic properties, and each was incubated with viable H. pylori in phosphate-buffered saline at pH 7.4 for 30 min, after which 100 mM urea was added and the amount of ammonia formed analyzed after a further 10 min. Inhibition between 0% and 100% at a 0.1 mM concentration was observed for the different analogues and could be expressed as a function of the pK(a)-value of the pyridine, the pK(a)-value of the benzimidazole, the overall lipophilicity, and, most importantly, the rate of sulfenamide formation, in a quantitative structure-activity relationship. The inhibition was potentiated by a lower pH (favoring the formation of the sulfenamide) but abolished in the presence of β- mercaptoethanol (a scavenger of the sulfenamide). Structural analogues incapable of yielding the sulfenamide did not inhibit ammonia production. Treatment of Helicobacter felis-infected mice with 230 μmol/kg flurofamide b.i.d. for 4 weeks, known to potently inhibit urease activity in vivo, as a means of eradicating the infection, was tested and compared with the effect of 125 μmol/kg omeprazole b.i.d. for 4 weeks. Neither treatment proved efficacious.
- Kuhler,Fryklund,Bergman,Weilitz,Lee,Larsson
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p. 4906 - 4916
(2007/10/03)
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- 2--1H-thienoimidazoles. A Novel Class of Gastric H+/K+-ATPase Inhibitors
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2-thienoimidazoles were synthesized and investigated as potential inhibitors of gastric H+/K+-ATPase.The isomers of the two possible thienoimidazole series were found to be potent inhibitors of gastric acid secretion in vitro and in vivo.Structure-activity relationships indicate that especially lipophilic alkoxy, benzyloxy, and phenoxy substituents with additional electron-demanding properties in the 4-position of the pyridine moiety combined with an unsubstituted thienoimidazole lead to highly active compounds with a favorable chemical stability.Various substitution patterns in the thienoimidazole moiety result in lower biological activity.The heptafluorobutyloxy derivative saviprazole (HOE 731, 5d) was selected for further development and is currently undergoing clinical evaluation.Comprehensive pharmacological studies indicate a pharmacodynamic profile different to omeprazole, the first H+/K+-ATPase blocker introduced on the market.
- Weidmann, Klaus,Herling, Andreas W.,Lang, Hans-Jochen,Scheunemann, Karl-Heinz,Rippel, Robert,et al.
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p. 438 - 450
(2007/10/02)
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- (H+,K+)-ATPase inhibiting 2-[(2-pyridylmethyl)sulfinyl]benzimidazoles. 4. A novel series of dimethoxypyridyl-substituted inhibitors with enhanced selectivity. The selection of pantoprazole as a clinical candidate
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[(Pyridylmethyl)sulfinyl]benzimidazoles 1 (PSBs) are a class of highly potent antisecretory (H+,K+)-ATPase inhibitors which need to be activated by acid to form their active principle, the cyclic sulfenamide 4. Selective inhibitors of the (H+,K+)-ATPase in vivo give rise to the nonselective thiophile 4 solely at low pH, thus avoiding interaction with other thiol groups in the body. The propensity to undergo the acid-catalyzed transformation is dependent on the nucleophilic/electrophilic properties of the functional groups involved in the formation of 2 since this step is both rate-determining and pH-dependent. The aim of this study was to identify compounds with high (H+,K+)-ATPase inhibitory activity in stimulated gastric glands possessing acidic pH, but low reactivity (high chemical stability) at neutral pH as reflected by in vitro (Na+,K+)-ATPase inhibitory activity. The critical influence of substituents flanking the pyridine 4-methoxy substituent present in all derivatives was carefully studied. The introduction of a 3-methoxy group gave inhibitors possessing a combination of high potency, similar to omeprazole and lansoprazole, but increased stability. As a result of these studies, compound 1a (INN pantoprazole) was selected as a candidate drug and is currently undergoing phase III clinical studies.
- Kohl,Sturm,Senn-Bilfinger,Simon,Kruger,Schaefer,Rainer,Figala,Klemm
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p. 1049 - 1057
(2007/10/02)
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- Fluoroalkoxy substituted benzimidazoles useful as gastric acid secretion inhibitors
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Fluoroalkoxy compounds of the general formula I STR1 wherein R1 represents a 1-3C-alkyl radical which is completely or predominantly substituted by fluorine, or a chlorodifluoromethyl radical, R1' represents hydrogen, halogen, trifluoromethyl, a 1-3C-alkyl radical, or a 1-3C-alkoxy radical which is optionally completely or predominantly substituted by fluorine, R2 represents hydrogen or a 1-3C-alkyl radical, R3 represents hydrogen or a 1-3C-alkyl or 1-3C-alkoxy radical, R4 represents hydrogen or a 1-3C-alkyl radical and n represents the number 0 or 1, and their salts are new compounds with a marked protective effect on the stomach.
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