2/11/2004
FARM 2147 Fluoroquinolones
28
Is there a SAR for emergence of resistance ?
The "Mutant Prevention Concentration" *

"When Mycobacterium bovis BCG and Staphylococcus aureus were plated on agar containing increasing concentrations of fluoroquinolone, colony numbers exhibited a sharp drop, followed by a plateau and a second sharp drop.
  The plateau region correlated,vith the presence of first-step resistant mutants. Mutants were not recovered at concentrations above those required for the second sharp drop, thereby defining a mutant prevention concentration (MPC).
A C8-methoxy group lowered the MPC for an N-1-cyclopropyl fluoroquinolone"