Enhanced Effectiveness of Intraperitoneal Antibiotics Administered via Liposomal Carrier

Abstract
• The local application of antibiotics to treat intraperitoneal contamination has been used with variable results. Liposomes are not rapidly absorbed from the peritoneal cavity, offering a potential delivery system for intraperitoneal antibiotics. The effects of liposome-incorporated antibiotic administration in a fecal peritonitis model were compared with the effects of conventional intraperitoneal and intramuscular antibiotics. Rats were divided into four groups: untreated, intramuscular cefoxitin, intraperitoneal cefoxitin, and intraperitoneal liposome-incorporated cefoxitin. Quantitative blood cultures were drawn at 4 and 24 hours. Liposome delivery of cefoxitin significantly reduced mortality and bacteremia at 4 and 24 hours compared with control subjects and conventional antibiotic groups. Peritoneal abscess formation tended to decrease in the liposome antibiotic group (mean ± SEM, 6.86 ± 0.79) compared with the group receiving free intraperitoneal administration of antibiotics (10.33± 1.63). We conclude that liposomal delivery significantly enhances the effectiveness of cefoxitin in this model of peritonitis. (Arch Surg. 1989;124:1411-1415)