Penetration of ampicillin and sulbactam into human costal cartilage

The question of whether ampicillin and sulbactam are able to penetrate sufficiently into costal cartilage tissue was investigated in 21 children undergoing surgery for funnel chest malformations. The concentrations of both compounds were determined in the core and mantle pieces of samples taken 45 min or 120 min after infusion of ampicillin/sulbactam (33.3/16.7 mg/kg bodyweight) preoperatively for antibiotic prophylaxis. Ampicillin was determined by bioassay and sulbactam was determined by gas-chromatography/mass spectrometry. Mean concentrations of ampicillin were 23.3 mg/kg and 10.4 mg/kg at 45 min and at 27.4 mg/kg and 7.8 mg/kg 120 min in the mantle and core piece, respectively. Mean concentrations of sulbactam were at the same time 21.3 mg/kg and 9.7 mg/kg and 17.5 mg/kg and 11.9 mg/kg, respectively. These values indicate that both compounds achieve high concentrations even in bradytrophic tissue such as cartilage. The concentrations exceed the MIC values of important bacterial pathogens involved in postoperative wound infections. Therefore ampicillin protected by sulbactam appears to be a well-suited agent for perioperative prophylaxis in thoracic surgery.