Ghorpade and coworkers from AstraZeneca® (AstraZeneca R&D, Bangalore, India) have discovered a quinolone derivative as a promising antituberculosis agent. The authors have assessed several properties of the lead compound (21) (Figure 8), including mechanism of action studies, in vitro/in vivo pharmacokinetics and drug metabolism. This quinoline derivative presented MIC90 values ranging from 0.2 to 3.12 μM against several single drug-resistant strains. The authors showed that the target of compound (21) is the mycobacterial DprE1 enzyme. In addition, in vivo pharmacokinetics studies pointed out compound (21) with Cmax of 4.9 μM, plasma clearance of 34.4 mL/min/kg and T1/2 of 0.5 h . A series of quinazolinone derivatives have been reported, showing potent antitubercular activity . Compound (22) (Figure 8) exhibited MIC90 of 6.6 μM against several MDR and XDR-TB clinical isolates. In addition, the authors suggested that the Mtb acetohydroxy-acid synthase (AHAS) is the target of these quinazolinone derivatives . AHAS is an enzyme that plays an important role in the branched-chain amino acids (BCAAs) biosynthetic pathway and its inhibition seems to be a potential target for anti-TB drugs .