Chloramphenicol diacetate

Based on the observation that chloramphenicol (CAP)-imprinted polymer possessed a modest affinity for chloramphenicol-methyl red (CAP-MR), Levi et al. [65] designed an intriguing MIP sensor to monitor the change of CAP in patients blood (Fig. 6). The presence of CAP in blood leads to a competitive displacement of CAP-MR from the imprinted cavities. The displaced composite is subsequently monitored at 460 nm. After optimizing the flow rate and concentration of CAP-MR in acetonitrile mobile phase, the response of this system to CAP, thiamphenicol (TAM), and chloramphenicol diacetate (CAP-DA) was determined (Fig. 7). As observed for CAP, there was a linear correlation over the range 1-1000 pg/mL. However, for CAP-DA almost no appreciable response was achieved, even if it was injected to 1000 pg/mL. As also observed, the value for CAP was about 40% higher than that for TAM at the same concentration. This revealed that CAP could compete more efficiently with the bound CAP-MR than TAM did. Further information showed that this method was adequate for detection below and above the recommended therapeutic range (10-20 pg/mL serum, potentially toxic above 25 pg/mL). 

Resistance to chloramphenicol is mediated by the synthesis of the 1-acetate and 1,3-diacetate while the corresponding resistance to streptomycin involves phosphorylation. 

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