Enhanced liposome-mediated antibacterial activity of piperacillin and gentamicin against gram-negative bacilli in vitro.

This study showed that encapsulation of piperacillin (PIP) and gentamicin (GE) by liposomes prepared with phosphatidylcholine and cholesterol (1:1) enhanced the antibiotic activity against gram negative bacilli. This was demonstrated by growth inhibition of Escherichia coli and Pseudomonas aeruginosa in the presence of the liposomal preparations containing either PIP or GE at 50 per cent MIC. Mixtures of liposomes containing buffer and either PIP or GE also exhibited an enhanced activity of the drug against the micro-organisms.