Correction of prior estimate of the biological activity of an N-trifluoroacetyl analogue of D-threo-chloramphenicol relative to chloramphenicol.

The inhibitory rate constants, k, for the inhibition of the rate of Escherichia coli generation at various concentrations, C, of chloramphenicol nad its N-trifluoroacetyl analogue were determined in vitro in accordance with kapp = k0 - kC where kapp is the apparent first-order generation rate constant at a drug concentration C and k0 is that constant in the absence of drug. The activity of the analogue was one-tenth that of chloramphenicol in contrast to a previously reported value.