[View of development of fluoroquinolones]

The global resurgence of tuberculosis and the emergence of multidrug-resistant tuberculosis have emphasized an urgent need for new, effective antimycobacterial drugs. A new antimycobacterial drugs should have a different mechanism of action to the standard drugs and should not show cross-resistance with them. Favorable pharmacokinetic properties, low incidence of side effects and low cost are the characteristics that would make antimycobacterial drugs suitable for extensive use. The fluoroquinolones would appear to fulfill most of the criteria for an ideal class of antimycobacterial drugs. The fluoroquinolones have been proposed for the treatment of Mycobacterium tuberculosis (M. tuberculosis) infections, with the results of in vitro, animal model and clinical studies suggesting that ofloxacin, ciprofloxacin, sparfloxacin and levofloxacin are the most promising of these drugs. However, these fluoroquinolones should not be used as first-line drugs, but rather, they should be reserved for treatment of tuberculosis that is resistant to rifampicin and isoniazid. Recently, a new investigational fluoroquinolone derivative, AM-1155, DU-6859a and CS-940, have excellent in vitro activity against M. tuberculosis, further studies are required to assess its clinical activity. We discussed the future of view of development of fluoroquinolones for mycobacterial diseases on the basis of structure-activity and structure-side-effect relationship studies. The comparative analysis enabled us to elucidate the structural requirements for the antimycobacterial activity and side-effects of fluoroquinolones. In addition, we summarized the newer methods for high-throughput screening of compounds against M. tuberculosis and discussed the problem of development of fluoroquinolones for mycobacterial diseases.