Glycocinnamoylspermidines, a new class of antibiotics. V. Antibacterial evaluation of the isopropyl derivative of LL-BM123gamma.

Isopropyl LL-BM123gamma, a novel semisynthetic glycocinnamoylspermidine antibiotic, was active in vitro against both Gram-negative and Gram-positive bacteria with broad spectrum bactericidal activity against clinically important Gram-negative strains. In parallel tests, it was equal to or more potent than reference aminoglycoside antibiotics against Escherichia coli, Proteus, Enterobacter-Klebsiella, Serratia, Salmonella, and Acinetobacter strains. Against clinical isolates of Pseudomonas aeruginosa, isopropyl LL-BM123gamma compared favorably with gentamicin, verdamicin and amikacin but was less potent than tobramycin. Isopropyl LL-BM123gamma was active against many Gram-negative bacteria that were relatively resistant to aminoglycosides. It was rapidly absorbed following subcutaneous administration in mice and showed greater potency than gentamicin on both dosage and plasma concentration bases against several experimental infections.