• Archives of Pharmacal Research
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• v.24 no.4
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• pp.270-275
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• 2001

Bioisostere approach has been shown to be useful to augment potency or to modify certain physiological properties of a lead compound. Based upon well documented bioisosterism, an isosteric replacement of benzene ring of 4-hydroxy-2-quinolone compound (L-695902) with a thiophene moiety was carried out to prepare the title compounds, 4-hydroxy-6-oxo-6,7-dihydro-thieno[2,3-b] pyrimidines 15. The resulting bioisosteric compounds 15 were evaluated for their antagonistic activity (birding assay) for NMDA receptor glycine site.

• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.849-854
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• 2000

The protonation and divalent cation complexation equilibria of several quinolone antibiotics such as nalidixic acid (NAL),flumequine (FLU), oxolinic acid (OXO), ofloxacin (OFL), norfloxacin (NOR) and enoxacin (ENO) have been examined by potentiome tric titration and spectrophotometric method. The antibacterial activity of these drugs depends upon the pH and the concentration of metal cations such as Mg2+ , Ca2+ in solu-tion. The apparent ionization constants of NAL, FLU, OXO, OFL, NOR and ENO in aqueous solution were found to be 6.33, 6.51, 6.72, 7.18, 7.26, and 7.53, respectively. In aqueous solution, NAL, FLU and OXO were found to be present mainly as two chemical species : molecularand anionic; but OFL, NOR and ENO were present mainly as three chemical species : anionic, neutral zwitterionic and cationic form, in equilibrium. The pKa1 and pKa2are found to be 6.10 and 8.28 for OFL; 6.23 and 8.55 for NOR; 6.32 and8.62 for ENO, respec-tively. The complex formation constants between OFL, NOR or FLU and some divalent cations are measured at pH 7.5. The 1 : 1 complexes are formed mainly by ion-dipole interaction. FLU has somewhat larger Kf values than OFL and NOR because its molecular size is small and the FLU is present asanionic form at pH 7.5.

• YAKHAK HOEJI
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• v.52 no.3
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• pp.219-224
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• 2008

Clinically isolated methicillin-resistant Staphylococcus aureus strains were exposed to subinhibitory concentration of DW286, DW-224a, gemifloxacin, trovafloxacin, sparfloxacin and ciprofloxacin during 26- to 39-days period. Subculturing led to resistance development, and most of the selected mutants were above susceptible breakpoints. Selected mutants had broad cross resistance to other quinolone antibiotics and only one mutant was completely susceptible to all fluoroquinolones. Twenty five among 42 mutants revealed mutations on DNA gyrase and topoisomerase IV by sequencing. Also 16 mutants had fluoroquinolones MICs that were 4-32 times lower in the presence of reserpine. In conclusion, alterations in DNA gyrase or topoisomerase IV and action of efflux pumping out system are the resistance mechanisms of DW-224a.

• YAKHAK HOEJI
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• v.38 no.5
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• pp.586-594
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• 1994

The general pharmacological effects of DWQ-013, a new synthetic quinolone antibacterial agent, were examined on the central nervous system in experimentral animals and the following results were obtained. Drug interaction of DWQ-013 with theophylline, fenbufen and nonsteroidal antiinflammatory drugs was also examined. DWQ-013 decreased touch escape effect on the general behavior and decreased body temperature at a concentration of 1000 mg/kg in mice. But DWQ 013 had no effect on the locomotor activity, rotarod perfomance and traction test in mice. Furthermore, DWQ-013 increased pentobarbital-induced sleeping time and affected the onset time in acetic acid-induced writhing test in mice. DWQ-013 reduced onset time and death time on strychnine-induced convulsions and death time on pentylenetetrazole-induced convulsions at a concentration of 1000 mg/kg in mice. But, the drug had no effect on the electroshock. DWQ-013 did not interact with fenbufen and any other NSAIDs but it did interact with theophylline. From these results, it could be suggested that DWQ-013 had less pharmacological effect than other quinolones on the central nervous system.

• Korean Journal of Veterinary Service
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• v.36 no.4
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• pp.311-320
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• 2013

The purpose of this study was to evaluate detecting methods and the relationship between tissues and blood for enrofloxacin and metabolic ciprofloxacin residues in broiler chickens. Two groups of broiler chickens were administrated via the drinking water with $50{\mu}g/mL$ and $100{\mu}g/mL$ of enrofloxacin for 5 days, respectively. The concentration of enrofloxacin and metabolic ciprofloxacin in tissues (muscle and kidney) and blood were measured during administration period (for 5 days) and withdrawal period (for 12 days) by high performance liquid chromatography (HPLC) method. Also, all samples were conducted for screening of residues by microbial method using E. coli for quinolone detection and immuno-chromatography method using Smart kit. The relationship between tissues (muscle and kidney) and blood for enrofloxacin and metabolic ciprofloxacin residues in broiler chickens was followed : The levels of enrofloxacin and metabolic ciprofloxacin residues in muscle and kidney were higher 2.9~3.2 folds, 3.6~3.8 folds more than the residues levels in blood, respectively. These results support we can predict the residues in muscle and kidney from the residues in blood. In comparison of detecting methods for antibiotic residues, microbial method using E. coli for quinolone detection and immuno-chromatography method using Smart kit could detect positive reaction at similar or lower concentration than violative concentration of enrofloxacin and metabolic ciprofloxacin in chicken tissues. These results support what two screening methods are useful for screening of quinolone detection in chickens.

• YAKHAK HOEJI
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• v.45 no.4
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• pp.334-338
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• 2001

A series of (-)-9-fluoro-2,3-dihydro-3(S)-methyl-10-(4-substituted-1-piperazinyl)-7-oxo-7H-pyrido [1,2,3-de] [1,4]-benzoxazine-6-carboxylic acid (5-8) was synthesized and evaluated for antibacterial activity against gram(+) and gram(-) bacteria. These synthesized compounds showed a lower activity than levofloxacin.

• Bulletin of the Korean Chemical Society
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• v.29 no.11
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• pp.2103-2108
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• 2008

• YAKHAK HOEJI
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• v.43 no.1
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• pp.131-133
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• 1999

The bactericidal activities of DW-116, a new fluoroquinolone was estimated by comparing the minimal bactericidal concentrations (MBCs) of it against some Gram-positive and -negative bacterial strains with the minimal inhibitory concentrations (MICs). The MBCs against the test organisms were equal to or two times higher than MICs. The results support that the antibacterial activity of DW-116 is bactericidal.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.376-379
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• 1990

To find out a correlation between antibacterial activity and physical properties of 7-substituted 1-ethyl-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid, dipole moments, charge distributions, and hydrophobicities were calculated. The atomic charges and the dipole moments to not give any correlations with inhibition of DNA gyrase, but the calculated hydration free energies show some correlations.

• Bulletin of the Korean Chemical Society
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• v.19 no.6
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• pp.667-671
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• 1998

A series of 1-aryl-lH-pyrazolo[4,3-c]quinolines and 2-aryl-2H-pyrazolo[4,3-c]quinolines are prepared by reacting 3-acyl-4-chloroquinolines in ethanol or 3-acyl-4(lH)-quinolone in acetic acid with appropriate hydrazines as possible anti-ulcer agents. A regiospecific synthesis of 1-aryl-lH-pyrazolo[4,3-c]quinolines is also achieved. The central pyridine ring could be easily reduced by catalytic hydrogenation.