Chemotherapeutic Activity of Carfecillin, the α-Phenyl Ester of Carbenicillin, in the Treatment of Experimental Mouse Infections

Summary

Carfecillin, the α-phenyl ester of carbenicillin was well absorbed after oral administration to infected and uninfected mice producing significant blood concentrations of carbenicillin whereas carbenicillin generally failed to produce detectable levels in mice by the oral route. Carfecillin showed activity of the same order as parenteral carbenicillin in the treatment of various intraperitoneal infections in mice including infections caused by certain ampicillin-resistant bacteria. Carfecillin was also effective in the treatment of experimental pyelonephritis in mice and was as active as parenteral carbenicillin in the treatment of renal infections caused by Pseudomonas aeruginosa and Escherichia coli.

Carbenicillin is widely used in the treatment of infections due to Gram-negative bacilli including Pseudomonas aeruginosa and other antibiotic-resistant bacteria (indole-positive Proteus, Serratia marcescens Providencia) but the compound is poorly absorbed by the oral route and must be administered by injection. However, certain a-esters of carbenicillin have been shown to be absorbed after oral administration to animals or man, and to be hydrolysed rapidly in vivo to liberate carbenicillin (English et al, 1972, Clayton et al, 1975). This report describes the activity of one such ester, carfecillin, the α-phenyl ester of carbenicillin, in the treatment of experimental mouse infections.