Cefpodoxime, as known as R 3763, is a metabolite of cefpodoxime proxetil. It is demonstrated that cefpodoxime, as an oral third generation cephalosporin antibiotic, is active against most Gram-positive and Gram-negative bacteria.

Cefpodoxime suppresses bacterial septum and cell wall synthesis by binding to penicillin-binding proteins (PBPs) located in the bacterial cytoplasmic membrane.

In vitro: Cefpodoxime showed antibacterial activities against obligatory anaerobes and salmonella spp., shigella spp. and Neisseria meningitides. The activity of cefpodoxime was less active than R95867, an active form of CS-834, against Gram-negative bacteria [1]. Cefpodoxime was quite stable to hydrolysis by β-lactamases produced from B. cereus and E. coli HB101/pBR322 [2].

In vivo: Male ddY mice were administered orally in a volume of 0.2 mL of 0.5% carboxymethyl cellulose sodium salt. After 7 days, it was shown that cefpodoxime had good efficacy against streptococcus spp. and K. pneumoniae infection in mice [1].

References:
[1].  Sakagawa, E., Otsuki, M., Oh, T., & Nishino, T. In-vitro and in-vivo antibacterial activities of CS-834, a new oral carbapenem. Journal of Antimicrobial Chemotherapy, 1998; 42: 426-437.
[2].  Fukuoka, T., Ohya, S., Utsui, Y., Domon, H., Takenouchi, T., Koga, T., … Kuwahara, S. In vitro and in vivo antibacterial activities of CS-834, a novel oral carbapenem. Antimicrobial Agents and Chemotherapy, 1997; 41(12): 2652–2663.