Zusammenfassung
Die Aktivität von zehn verschiedenen antibakteriellen Substanzen der 4-Chinolon-Gruppe gegenEscherichia coli KL 16 wurde bei pH-Werten zwischen 5,6 und 8,3, dem pH-Bereich von Urin, geprüft. Der pH beeinflußte die minimalen Hemmkonzentrationen aller Substanzen, doch bestimmte der Substituent in Position C7 bei jedem der 4-Chinolone, in welcher Weise seine Aktivität durch die Wasserstoffionenkonzentration verändert wurde. Wenn ein 4-Chinolon in Position C7 eine Piperazin-Gruppe hatte, nahm seine Aktivität mit absinkendem pH immer mehr ab. Hingegen zeigten alle Medikamente, bei denen in C7 kein Piperazin-Substituent vorlag, unabhängig von der Art ihre Substituenten mit sinkendem pH eine zunehmend ansteigende Aktivität. Außerdem stellte sich heraus, daß Magnesium im Urin mit Ausnahme von Cinoxacin alle geprüften 4-Chinolone bei allen untersuchten pH-Werten antagonistisch beeinflußte.
Summary
The activity of ten different 4-quinolone antibacterial agents againstEscherichia coli KL16 was investigated at four pH values between 5.6 and 8.3, which is the pH range of urine. It was found that pH affected the minimum inhibitory concentrations of all the drugs, but the nature of the substituent at the C7 position of each 4-quinolone governed how its activity was altered by the hydrogen ion concentration. When a 4-quinolone possessed a piperazine group at its C7 position its activity became progressively less as the pH fell. However, all drugs that lacked a C7 piperazine, irrespective of the nature of their substituent at this position, exhibited a progressive increase in activity as the pH was reduced. In addition it was found that, excepting cinoxacin, a urinary concentration of magnesium generally caused a further antagonism of the activity of the nine other 4-quinolone antibacterials at all pH values tested.
Literatur
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Smith, J.T., Ratcliffe, N.T. Einfluß von pH-Wert und Magnesium auf die antibakterielle Aktivität von Chinolonpräparaten. Infection 14 (Suppl 1), S31–S35 (1986). https://doi.org/10.1007/BF01645195
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DOI: https://doi.org/10.1007/BF01645195