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Fritz Sörgel - One of the best experts on this subject based on the ideXlab platform.
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urinary bactericidal activity and pharmacokinetics of Enoxacin versus norfloxacin and ciprofloxacin in healthy volunteers after a single oral dose
The Journal of Urology, 1999Co-Authors: Michaela Well, Kurt G. Naber, Martina Kinzigschippers, Fritz SörgelAbstract:In an open, randomised monocentric crossover study in six male and six female healthy volunteers, the urinary antibacterial activity and pharmacokinetics of Enoxacin, norfloxacin and ciprofloxacin were assessed. Urine was collected up to 6 days, and venous blood samples up to 12 h, after a single oral dose of 400 mg Enoxacin, 400 mg norfloxacin and 500 mg ciprofloxacin. Enoxacin (250 mg:l) demonstrated the highest peak concentration (median) in the urine (0‐6 h), followed by ciprofloxacin (237 mg:l) and norfloxacin (157 mg:l) as determined by the HPLC assay. The total amount (mean) excreted by the kidneys as parent drugs were as follows: Enoxacin 54% of dose, ciprofloxacin 33% of dose, and norfloxacin 22% of dose. The mean plasma concentrations decreased from 1 to 4 h after administration for Enoxacin from 1.9 to 1.4 mg:l, for ciprofloxacin from 2.0 to 0.8 mg:l and for norfloxacin from 1.3 to 0.5 mg:l. The antibacterial activity in urine was determined as urinary bactericidal titers (UBT), i.e. the highest 2-fold dilution of urine still bactericidal for the reference organism (E. coli ATCC 25922) and for five uropathogens with minimal inhibitory (MIC) and bactericidal (MBC) concentrations ranging from highly susceptible to resistant cultured from the urine of patients with complicated urinary tract infections (UTI). For the E. coli ATCC 25922, the organism with the lowest MIC, median UBTs of ciprofloxacin were present for 4 days, decreasing from 1:512 to 1:2, that of Enoxacin for 2 days, decreasing from 1:256 to 1:4, and that of norfloxacin for 2 days, decreasing from 1:128 to 1:2. For the five uropathogens (with increasing MICs: K. pneumoniae, P. mirabilis, E. coli (resistant to nalidixic acid), P. aeruginosa and E. faecalis), the UBTs decreased in general, according to MICs, demonstrating the same relations of UBTs for ciprofloxacin (highest) versus Enoxacin (medium) versus norfloxacin (lowest) with one exception (P. mirabilis) for which norfloxacin showed higher UBTs than Enoxacin. The minimal urinary bactericidal concentrations (MUBC), as derived from urinary concentrations, and UBTs showed a fairly wide inter- and intraindividual range and were generally higher than the corresponding MBCs as determined in Mueller Hinton broth. In conclusion, according to antibacterial activity in urine determined as UBTs, a single oral dose of ciprofloxacin (500 mg) generally resulted in the highest and longest-lasting UBTs followed by that of Enoxacin (400 mg) and norfloxacin (400 mg). A dose of 400 mg Enoxacin can be expected to be at least equivalent if not superior to that of 400 mg norfloxacin. Only Enoxacin and ciprofloxacin exhibited urinary bactericidal activity against all test organisms up to 12 h in all individuals. Therefore, clinical comparison of Enoxacin versus ciprofloxacin in the treatment of complicated UTI could be worth testing. © 1998 Elsevier Science B.V.:International Society of Chemotherapy. All rights reserved.
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urinary bactericidal activity and pharmacokinetics of Enoxacin versus norfloxacin and ciprofloxacin in healthy volunteers after a single oral dose
International Journal of Antimicrobial Agents, 1998Co-Authors: Michaela Well, Kurt G. Naber, Martina Kinzigschippers, Fritz SörgelAbstract:In an open, randomised monocentric crossover study in six male and six female healthy volunteers, the urinary antibacterial activity and pharmacokinetics of Enoxacin, norfloxacin and ciprofloxacin were assessed. Urine was collected up to 6 days, and venous blood samples up to 12 h, after a single oral dose of 400 mg Enoxacin, 400 mg norfloxacin and 500 mg ciprofloxacin. Enoxacin (250 mg/l) demonstrated the highest peak concentration (median) in the urine (0-6 h), followed by ciprofloxacin (237 mg/l) and norfloxacin (157 mg/l) as determined by the HPLC assay. The total amount (mean) excreted by the kidneys as parent drugs were as follows: Enoxacin 54% of dose, ciprofloxacin 33% of dose, and norfloxacin 22% of dose. The mean plasma concentrations decreased from 1 to 4 h after administration for Enoxacin from 1.9 to 1.4 mg/l, for ciprofloxacin from 2.0 to 0.8 mg/l and for norfloxacin from 1.3 to 0.5 mg/l. The antibacterial activity in urine was determined as urinary bactericidal titers (UBT), i.e. the highest 2-fold dilution of urine still bactericidal for the reference organism (E. coli ATCC 25,922) and for five uropathogens with minimal inhibitory (MIC) and bactericidal (MBC) concentrations ranging from highly susceptible to resistant cultured from the urine of patients with complicated urinary tract infections (UTI). For the E. coli ATCC 25,922, the organism with the lowest MIC, median UBTs of ciprofloxacin were present for 4 days, decreasing from 1:512 to 1:2, that of Enoxacin for 2 days, decreasing from 1:256 to 1:4, and that of norfloxacin for 2 days, decreasing from 1:128 to 1:2. For the five uropathogens (with increasing MICs: K. pneumoniae, P. mirabilis, E. coli (resistant to nalidixic acid), P. aeruginosa and E. faecalis), the UBTs decreased in general, according to MICs, demonstrating the same relations of UBTs for ciprofloxacin (highest) versus Enoxacin (medium) versus norfloxacin (lowest) with one exception (P. mirabilis) for which norfloxacin showed higher UBTs than Enoxacin. The minimal urinary bactericidal concentrations (MUBC), as derived from urinary concentrations, and UBTs showed a fairly wide inter- and intraindividual range and were generally higher than the corresponding MBCs as determined in Mueller Hinton broth. In conclusion, according to antibacterial activity in urine determined as UBTs, a single oral dose of ciprofloxacin (500 mg) generally resulted in the highest and longest-lasting UBTs followed by that of Enoxacin (400 mg) and norfloxacin (400 mg). A dose of 400 mg Enoxacin can be expected to be at least equivalent if not superior to that of 400 mg norfloxacin. Only Enoxacin and ciprofloxacin exhibited urinary bactericidal activity against all test organisms up to 12 h in all individuals. Therefore, clinical comparison of Enoxacin versus ciprofloxacin in the treatment of complicated UTI could be worth testing.
Katsumi Miyazaki - One of the best experts on this subject based on the ideXlab platform.
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The Stimulative Effect of Diffusion Potential on Enoxacin Uptake across Rat Intestinal Brush-border Membranes
Journal of Pharmacy and Pharmacology, 1994Co-Authors: Takeshi Hirano, Mitsuru Sugawara, Michiya Kobayashi, Ken Iseki, Masahiko Takada, Shozo Miyazaki, Katsumi MiyazakiAbstract:Evidence of a membrane potential dependence for Enoxacin uptake by rat intestinal brush-border membrane vesicles has been found. The transient overshooting uptake of Enoxacin disappeared in the voltage-clamped brush-border membrane vesicles in the presence of an outward H(+)-gradient. Momentary dissipation of the H(+)-gradient itself by carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) did not affect the uptake of Enoxacin. In contrast, Enoxacin uptake was depressed by an interior positive K(+)-diffusion potential induced by valinomycin. Furthermore, not only the outward H(+)-gradient but also an inward Cl(-)-gradient caused a stimulating effect on Enoxacin uptake, and the stimulation by the Cl(-)-gradient was dissipated by using voltage-clamped membrane vesicles. These results indicate that Enoxacin transportation across the brush-border membrane is dependent on the ionic diffusion potential. On the other hand, neither Gly-Gly nor guanidine had any effect on Enoxacin uptake by the membrane vesicles in the presence of an inward (for Gly-Gly) or outward (for guanidine) H(+)-gradient as a driving force for each transport system. Therefore, it seems that Enoxacin transport through the intestinal epithelia does not participate in the carrier-mediated transport systems for Gly-Gly and guanidine.
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the ph dependent uptake of Enoxacin by rat intestinal brush border membrane vesicles
Journal of Pharmacy and Pharmacology, 1992Co-Authors: Ken Iseki, Mitsuru Sugawara, Takeshi Hirano, Masahiko Takada, Shozo Miyazaki, Yuko Fukushi, Yukie Kitamura, Hiroshi Saitoh, Katsumi MiyazakiAbstract:The mechanism of the intestinal transport of Enoxacin, an orally active fluoroquinolone antibiotic, has been investigated using brush-border membrane vesicles isolated from rat small intestine. The initial rate and time-course of Enoxacin uptake were considerably dependent upon the medium pH (pH 5.5 greater than pH 7.5) and upon the percent ionization of the carboxyl group (pKa 6.2, anionic charge), namely, the degree of uptake of cationic form was higher than that of the zwitterionic form. There was evidence of transport into the intravesicular space as shown by the effect of extravesicular medium osmolarity on Enoxacin uptake at steady state (30 min). This transport across the brush-border membrane was stimulated by the valinomycin-induced K(+)-diffusion potential (interior negative) and an outward H(+)-diffusion potential. Furthermore, changing the pH of the medium from 5.5 to 7.5 significantly decreased the effect of valinomycin-induced K(+)-diffusion potential on the Enoxacin uptake. These results suggest that the uptake behaviour of the cationic form of Enoxacin plays an important role in the intestinal absorption process of Enoxacin.
Michaela Well - One of the best experts on this subject based on the ideXlab platform.
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urinary bactericidal activity and pharmacokinetics of Enoxacin versus norfloxacin and ciprofloxacin in healthy volunteers after a single oral dose
The Journal of Urology, 1999Co-Authors: Michaela Well, Kurt G. Naber, Martina Kinzigschippers, Fritz SörgelAbstract:In an open, randomised monocentric crossover study in six male and six female healthy volunteers, the urinary antibacterial activity and pharmacokinetics of Enoxacin, norfloxacin and ciprofloxacin were assessed. Urine was collected up to 6 days, and venous blood samples up to 12 h, after a single oral dose of 400 mg Enoxacin, 400 mg norfloxacin and 500 mg ciprofloxacin. Enoxacin (250 mg:l) demonstrated the highest peak concentration (median) in the urine (0‐6 h), followed by ciprofloxacin (237 mg:l) and norfloxacin (157 mg:l) as determined by the HPLC assay. The total amount (mean) excreted by the kidneys as parent drugs were as follows: Enoxacin 54% of dose, ciprofloxacin 33% of dose, and norfloxacin 22% of dose. The mean plasma concentrations decreased from 1 to 4 h after administration for Enoxacin from 1.9 to 1.4 mg:l, for ciprofloxacin from 2.0 to 0.8 mg:l and for norfloxacin from 1.3 to 0.5 mg:l. The antibacterial activity in urine was determined as urinary bactericidal titers (UBT), i.e. the highest 2-fold dilution of urine still bactericidal for the reference organism (E. coli ATCC 25922) and for five uropathogens with minimal inhibitory (MIC) and bactericidal (MBC) concentrations ranging from highly susceptible to resistant cultured from the urine of patients with complicated urinary tract infections (UTI). For the E. coli ATCC 25922, the organism with the lowest MIC, median UBTs of ciprofloxacin were present for 4 days, decreasing from 1:512 to 1:2, that of Enoxacin for 2 days, decreasing from 1:256 to 1:4, and that of norfloxacin for 2 days, decreasing from 1:128 to 1:2. For the five uropathogens (with increasing MICs: K. pneumoniae, P. mirabilis, E. coli (resistant to nalidixic acid), P. aeruginosa and E. faecalis), the UBTs decreased in general, according to MICs, demonstrating the same relations of UBTs for ciprofloxacin (highest) versus Enoxacin (medium) versus norfloxacin (lowest) with one exception (P. mirabilis) for which norfloxacin showed higher UBTs than Enoxacin. The minimal urinary bactericidal concentrations (MUBC), as derived from urinary concentrations, and UBTs showed a fairly wide inter- and intraindividual range and were generally higher than the corresponding MBCs as determined in Mueller Hinton broth. In conclusion, according to antibacterial activity in urine determined as UBTs, a single oral dose of ciprofloxacin (500 mg) generally resulted in the highest and longest-lasting UBTs followed by that of Enoxacin (400 mg) and norfloxacin (400 mg). A dose of 400 mg Enoxacin can be expected to be at least equivalent if not superior to that of 400 mg norfloxacin. Only Enoxacin and ciprofloxacin exhibited urinary bactericidal activity against all test organisms up to 12 h in all individuals. Therefore, clinical comparison of Enoxacin versus ciprofloxacin in the treatment of complicated UTI could be worth testing. © 1998 Elsevier Science B.V.:International Society of Chemotherapy. All rights reserved.
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urinary bactericidal activity and pharmacokinetics of Enoxacin versus norfloxacin and ciprofloxacin in healthy volunteers after a single oral dose
International Journal of Antimicrobial Agents, 1998Co-Authors: Michaela Well, Kurt G. Naber, Martina Kinzigschippers, Fritz SörgelAbstract:In an open, randomised monocentric crossover study in six male and six female healthy volunteers, the urinary antibacterial activity and pharmacokinetics of Enoxacin, norfloxacin and ciprofloxacin were assessed. Urine was collected up to 6 days, and venous blood samples up to 12 h, after a single oral dose of 400 mg Enoxacin, 400 mg norfloxacin and 500 mg ciprofloxacin. Enoxacin (250 mg/l) demonstrated the highest peak concentration (median) in the urine (0-6 h), followed by ciprofloxacin (237 mg/l) and norfloxacin (157 mg/l) as determined by the HPLC assay. The total amount (mean) excreted by the kidneys as parent drugs were as follows: Enoxacin 54% of dose, ciprofloxacin 33% of dose, and norfloxacin 22% of dose. The mean plasma concentrations decreased from 1 to 4 h after administration for Enoxacin from 1.9 to 1.4 mg/l, for ciprofloxacin from 2.0 to 0.8 mg/l and for norfloxacin from 1.3 to 0.5 mg/l. The antibacterial activity in urine was determined as urinary bactericidal titers (UBT), i.e. the highest 2-fold dilution of urine still bactericidal for the reference organism (E. coli ATCC 25,922) and for five uropathogens with minimal inhibitory (MIC) and bactericidal (MBC) concentrations ranging from highly susceptible to resistant cultured from the urine of patients with complicated urinary tract infections (UTI). For the E. coli ATCC 25,922, the organism with the lowest MIC, median UBTs of ciprofloxacin were present for 4 days, decreasing from 1:512 to 1:2, that of Enoxacin for 2 days, decreasing from 1:256 to 1:4, and that of norfloxacin for 2 days, decreasing from 1:128 to 1:2. For the five uropathogens (with increasing MICs: K. pneumoniae, P. mirabilis, E. coli (resistant to nalidixic acid), P. aeruginosa and E. faecalis), the UBTs decreased in general, according to MICs, demonstrating the same relations of UBTs for ciprofloxacin (highest) versus Enoxacin (medium) versus norfloxacin (lowest) with one exception (P. mirabilis) for which norfloxacin showed higher UBTs than Enoxacin. The minimal urinary bactericidal concentrations (MUBC), as derived from urinary concentrations, and UBTs showed a fairly wide inter- and intraindividual range and were generally higher than the corresponding MBCs as determined in Mueller Hinton broth. In conclusion, according to antibacterial activity in urine determined as UBTs, a single oral dose of ciprofloxacin (500 mg) generally resulted in the highest and longest-lasting UBTs followed by that of Enoxacin (400 mg) and norfloxacin (400 mg). A dose of 400 mg Enoxacin can be expected to be at least equivalent if not superior to that of 400 mg norfloxacin. Only Enoxacin and ciprofloxacin exhibited urinary bactericidal activity against all test organisms up to 12 h in all individuals. Therefore, clinical comparison of Enoxacin versus ciprofloxacin in the treatment of complicated UTI could be worth testing.
Takeshi Hirano - One of the best experts on this subject based on the ideXlab platform.
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The Stimulative Effect of Diffusion Potential on Enoxacin Uptake across Rat Intestinal Brush-border Membranes
Journal of Pharmacy and Pharmacology, 1994Co-Authors: Takeshi Hirano, Mitsuru Sugawara, Michiya Kobayashi, Ken Iseki, Masahiko Takada, Shozo Miyazaki, Katsumi MiyazakiAbstract:Evidence of a membrane potential dependence for Enoxacin uptake by rat intestinal brush-border membrane vesicles has been found. The transient overshooting uptake of Enoxacin disappeared in the voltage-clamped brush-border membrane vesicles in the presence of an outward H(+)-gradient. Momentary dissipation of the H(+)-gradient itself by carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) did not affect the uptake of Enoxacin. In contrast, Enoxacin uptake was depressed by an interior positive K(+)-diffusion potential induced by valinomycin. Furthermore, not only the outward H(+)-gradient but also an inward Cl(-)-gradient caused a stimulating effect on Enoxacin uptake, and the stimulation by the Cl(-)-gradient was dissipated by using voltage-clamped membrane vesicles. These results indicate that Enoxacin transportation across the brush-border membrane is dependent on the ionic diffusion potential. On the other hand, neither Gly-Gly nor guanidine had any effect on Enoxacin uptake by the membrane vesicles in the presence of an inward (for Gly-Gly) or outward (for guanidine) H(+)-gradient as a driving force for each transport system. Therefore, it seems that Enoxacin transport through the intestinal epithelia does not participate in the carrier-mediated transport systems for Gly-Gly and guanidine.
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the ph dependent uptake of Enoxacin by rat intestinal brush border membrane vesicles
Journal of Pharmacy and Pharmacology, 1992Co-Authors: Ken Iseki, Mitsuru Sugawara, Takeshi Hirano, Masahiko Takada, Shozo Miyazaki, Yuko Fukushi, Yukie Kitamura, Hiroshi Saitoh, Katsumi MiyazakiAbstract:The mechanism of the intestinal transport of Enoxacin, an orally active fluoroquinolone antibiotic, has been investigated using brush-border membrane vesicles isolated from rat small intestine. The initial rate and time-course of Enoxacin uptake were considerably dependent upon the medium pH (pH 5.5 greater than pH 7.5) and upon the percent ionization of the carboxyl group (pKa 6.2, anionic charge), namely, the degree of uptake of cationic form was higher than that of the zwitterionic form. There was evidence of transport into the intravesicular space as shown by the effect of extravesicular medium osmolarity on Enoxacin uptake at steady state (30 min). This transport across the brush-border membrane was stimulated by the valinomycin-induced K(+)-diffusion potential (interior negative) and an outward H(+)-diffusion potential. Furthermore, changing the pH of the medium from 5.5 to 7.5 significantly decreased the effect of valinomycin-induced K(+)-diffusion potential on the Enoxacin uptake. These results suggest that the uptake behaviour of the cationic form of Enoxacin plays an important role in the intestinal absorption process of Enoxacin.
Ken Iseki - One of the best experts on this subject based on the ideXlab platform.
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The Stimulative Effect of Diffusion Potential on Enoxacin Uptake across Rat Intestinal Brush-border Membranes
Journal of Pharmacy and Pharmacology, 1994Co-Authors: Takeshi Hirano, Mitsuru Sugawara, Michiya Kobayashi, Ken Iseki, Masahiko Takada, Shozo Miyazaki, Katsumi MiyazakiAbstract:Evidence of a membrane potential dependence for Enoxacin uptake by rat intestinal brush-border membrane vesicles has been found. The transient overshooting uptake of Enoxacin disappeared in the voltage-clamped brush-border membrane vesicles in the presence of an outward H(+)-gradient. Momentary dissipation of the H(+)-gradient itself by carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) did not affect the uptake of Enoxacin. In contrast, Enoxacin uptake was depressed by an interior positive K(+)-diffusion potential induced by valinomycin. Furthermore, not only the outward H(+)-gradient but also an inward Cl(-)-gradient caused a stimulating effect on Enoxacin uptake, and the stimulation by the Cl(-)-gradient was dissipated by using voltage-clamped membrane vesicles. These results indicate that Enoxacin transportation across the brush-border membrane is dependent on the ionic diffusion potential. On the other hand, neither Gly-Gly nor guanidine had any effect on Enoxacin uptake by the membrane vesicles in the presence of an inward (for Gly-Gly) or outward (for guanidine) H(+)-gradient as a driving force for each transport system. Therefore, it seems that Enoxacin transport through the intestinal epithelia does not participate in the carrier-mediated transport systems for Gly-Gly and guanidine.
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the ph dependent uptake of Enoxacin by rat intestinal brush border membrane vesicles
Journal of Pharmacy and Pharmacology, 1992Co-Authors: Ken Iseki, Mitsuru Sugawara, Takeshi Hirano, Masahiko Takada, Shozo Miyazaki, Yuko Fukushi, Yukie Kitamura, Hiroshi Saitoh, Katsumi MiyazakiAbstract:The mechanism of the intestinal transport of Enoxacin, an orally active fluoroquinolone antibiotic, has been investigated using brush-border membrane vesicles isolated from rat small intestine. The initial rate and time-course of Enoxacin uptake were considerably dependent upon the medium pH (pH 5.5 greater than pH 7.5) and upon the percent ionization of the carboxyl group (pKa 6.2, anionic charge), namely, the degree of uptake of cationic form was higher than that of the zwitterionic form. There was evidence of transport into the intravesicular space as shown by the effect of extravesicular medium osmolarity on Enoxacin uptake at steady state (30 min). This transport across the brush-border membrane was stimulated by the valinomycin-induced K(+)-diffusion potential (interior negative) and an outward H(+)-diffusion potential. Furthermore, changing the pH of the medium from 5.5 to 7.5 significantly decreased the effect of valinomycin-induced K(+)-diffusion potential on the Enoxacin uptake. These results suggest that the uptake behaviour of the cationic form of Enoxacin plays an important role in the intestinal absorption process of Enoxacin.