Levofloxacin - Pharmacology

Pharmacology

Levofloxacin is the L-isomer of the racemate ofloxacin, a quinolone antimicrobial agent. In chemical terms, levofloxacin, a chiral fluorinated carboxyquinolone, is the pure (-)-(S)-enantiomer of the racemic drug substance ofloxacin. The chemical name is (-)-(S)-9fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido-1,4benzoxazine-6-carboxylic acid hemihydrate. The empirical formula is C₁₈H₂₀FN₃O₄ • ½ H2O, and the molecular weight is 370.38. Levofloxacin is a light-yellowish-white to yellow-white crystal or crystalline powder.

Some of the endogenous compounds that are affected by the levofloxacin include GABA receptors (inhibitor), OCTN2 (inhibitor), blood glucose (alteration) potassium channels (in myocardial cells - inhibitor), pancreatic β-cell potassium channels (inhibitor) and glutathione (depletor). Levofloxacin can be used effectively as a positive control in thorough QT/QTc studies in healthy volunteers and can fulfil the criteria for a positive comparator. The ICH E14 guidelines recommend a threshold of around 5 ms for a positive QT/QTc study. The largest time-matched difference in QTc for levofloxacin suggests the potential for use in more rigorous QT/QTc studies.