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"
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