Change in Vancomycin Absorption after Intraperitoneal Injection and Correlation between Intraperitoneal Vancomycin Absorption and Peritoneal Equilibration Test Score in Mice with Peritoneal Injuries

Abstract

Peritonitis is a serious complication in peritoneal dialysis patients and requires antibiotic administration. Intraperitoneal vancomycin is an empiric therapy for peritonitis caused by Gram-positive cocci; however, there is no way to predict vancomycin absorption after intraperitoneal administration. Therefore, we aimed to evaluate the changes in vancomycin absorption after intraperitoneal injection into mice with chlorhexidine gluconate (CG) induced peritoneal injuries. Additionally, we examined the correlation between intraperitoneal vancomycin absorption and peritoneal equilibration test (PET) score. PET score was determined using glucose concentration in the peritoneal dialysis fluid at each dwell time (D_t) and D₂ (2 h of dwell time)/D₀ (0 h of dwell time) glucose ratio. Vancomycin was injected into the peritoneal cavity of mice, blood was collected after 1–8 h, and peritoneal fluid was recovered. The residual ratio of intraperitoneal vancomycin was significantly decreased in the CG group at all time points compared to that in the vehicle group. CG group significantly exhibited higher serum vancomycin concentrations than the vehicle group, and the maximum serum concentration increased depending on CG concentration, with 0.05 and 0.1% CG groups showing 3.9- and 6.1-times higher vancomycin concentrations, respectively, than the vehicle group. A significant correlation was observed between the D_t/D₀ glucose ratios and residual vancomycin ratios in the peritoneal fluid 2 or 6 h after intraperitoneal injection. A good correlation was observed between the D₂/D₀ glucose and residual vancomycin ratios 6 h after intraperitoneal vancomycin injection. Thus, PET score can predict residual intraperitoneal vancomycin, aiding in dosing decisions.