ABSTRACT
Telithromycin (HMR 3647, Ketek®, Sanofi-Aventis, Bridgewater, NJ) is a semisynthetic ketolide analogue of the flagship macrolide antibiotic erythromycin A. Similar to macrolides, telithromycin exerts its bacteriostatic effect by binding reversibly to the 50S subunit of the bacterial ribosome and ultimately blocking bacterial protein synthesis. Unlike new generations of macrolides produced from synthetic modifications of existing macrolides, such as clarithromycin and azithromycin, telithromycin retains activity against macrolide-resistant bacterial pathogens due to alterations in its chemical structure (Agouridas et al., 1998). Although telithromycin retains the classic macrocyclic ring structure common to macrolide antibiotics, the L-cladinose moiety at position 3 of the erythronolide ring is replaced by a keto group giving rise to the ketolide name. In addition, an alkyl-aryl extension is added at positions 11 and 12 of the cyclic carbamate ring (Figure 64.1) (Pavlovic et al., 2014). These modifications in structure result in telithromycin’s improved antibacterial activity, increased bioavailability, and decreased incidence of adverse events, namely gastrointestinal intolerance, compared to macrolides (Denis et al., 1999). The molecular formula of telithromycin is C43H65N5O10 and the molecular weight of the drug is 812.00 (Zhanel et al., 2002). Chemical structure of telithromycin. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315152110/08d8042d-9481-4a8d-8c27-9bd589f6de6b/content/fig64_1.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
