セフィデロコル

Similarly to other cephalosporins, cefiderocol exerts bactericidal activity against a range of bacterial species. Cefiderocol has primarily shown efficacy against aerobic Gram negative bacteria including *Escherichia coli*, *Klebsiella pneumoniae*, and *Pseudomonas aeruginosa*.

Cefiderocol acts by binding to and inhibiting penicillin-binding proteins (PBPs), preventing cell wall synthesis and ultimately causing death of the bacterial cell. Like other β-lactam antibiotics cefiderocol is able to enter bacterial cells via passive diffusion through porins. Unlike other β-lactams, cefiderocol contains a chlorocatechol group which allows it to chelate iron. Once bound to ferric iron cefiderocol is able to undergo active transport into bacterial cells through iron channels in the outer cell membrane such as those encoded by the *cirA* and *fiu* genes in *E. coli* or the *PiuA* gene in *P. aeruginosa*. Once inside the cell, cefiderocol binds to and inhibits PBP3 with high affinity thereby preventing the linking of peptodoglycan layers via the pentapeptide bridge. PBP1a, 1b, 2,and 4 are also bound and inhibited by cefiderocol but with a lesser potency than PBP3 and are therefore expected to contribute less to its antibacterial effect.

Cefiderocol undergoes a small degree of metabolism to a cefiderocol epimer at the 7 position, cefiderocol catechol-3-methoxy and -4-methoxy, and a pyrrolidine chlorobenzamide product (PCBA). PCBA undergoes further metabolism to sulfated, methylated, and glucuronidated metabolites. The enzymes involved in these reactions have yet to be identified and cefiderocol has not been shown to interfere in the metabolism of other agents.

A single intravenous dose of 2 g of cefiderocol in healthy patients produces a Cmax of 89.7 mg/L and an AUC of 386 mg\*h/L. In patients with complicated urinary tract infections and a creatinine clearance of at least 60 mL/min, doses of 2 g cefiderocol every 8 hours produced an AUC of 394.7 mg*h/L and a Cmax of 138 mg/L. However the infusion rate for this chronic dosing was 3 times the recommended rate. Cmax and AUC are known to increase proportionally with dosage.