Structure--activity relationship of quinolones.

The understanding of some structure-activity relationships of quinolones allowed the development of the new fluorinated quinolones, compounds with a major clinical potential. The basic structure of these drugs consists of a substituted pyridine ring and a carboxylic acid ring. The substitution at the first position is vital for antibacterial activity, while the presence of a fluorine atom and a piperazine ring is responsible for a broader spectrum of activity and higher intrinsic potency. Further modifications at side-chains or on the ring structure provide compounds with different pharmacokinetic or/and antibacterial activity. A better understanding of these relationships and correlations with clinical results is essential for the design of new improved derivatives with therapeutic potential.