Pharmacokinetics of fluconazole and fosfluconazole after intraperitoneal administration to peritoneal dialysis rats.

Fluconazole (FLCZ) is an antifungal agent that is efficacious in the treatment of fungal peritonitis. Fosfluconazole (F-FLCZ) is the phosphate prodrug of FLCZ, which is highly soluble compared with FLCZ. F-FLCZ is useful against fungal peritonitis in continuous ambulatory peritoneal dialysis (CAPD) patients because it has a high water solubility. The aims of the present study were to characterize the peritoneal permeability of FLCZ and the pharmacokinetics of FLCZ and F-FLCZ after intraperitoneal (i.p.) administration to peritoneal dialysis rats. FLCZ or F-FLCZ was administered intravenously and intraperitoneally. After the i.p. administration of F-FLCZ, FLCZ was detected in circulating blood and the dialyzing fluid in peritoneal dialysis rats. The concentration of plasma FLCZ after the i.p. F-FLCZ administration was lower than that after the intravenous (i.v.) F-FLCZ administration. It is considered that the dose should be increased appropriately when F-FLCZ is administered intraperitoneally. The profiles of plasma FLCZ after i.v. and i.p. administrations were analyzed using a two-compartment model in which the distribution volume of the peripheral compartment was fixed at a volume of the dialyzing fluid (peritoneal dialysis PK model). The peritoneal dialysis PK model could describe the profiles of plasma and dialyzing fluid FLCZ. These results suggest that FLCZ and F-FLCZ could be administered intraperitoneally for the treatment of fungal peritonitis in CAPD patients.