Uptake and intracellular activity of fluconazole in human polymorphonuclear leukocytes

Abstract

The penetration of fluconazole into human polymorphonuclear leukocytes (PMNs) and tissue culture epithelial cells (McCoy) was evaluated. At different extracellular concentrations (0.5 to 10 mg/liter), fluconazole reached cell-associated concentrations greater than the extracellular ones in either human PMNs (intracellular concentration to extracellular concentration ratio, ≥2.2) or McCoy cells (intracellular concentration to extracellular concentration ratio, ≥1.3). The uptake of fluconazole by PMNs was rapid and reversible but was not energy dependent. The intracellular penetration of fluconazole was not affected by environmental pH or temperature. Ingestion of opsonized zymosan and opsonized Candida albicans did not significantly increase the amount of PMN-associated fluconazole. At therapeutic extracellular concentrations, the intracellular activity of fluconazole against C. albicans in PMNs was significantly lower than that of amphotericin B. It was concluded that fluconazole reaches high intracellular concentrations within PMNs but shows moderate activity against intracellular C. albicans in vitro.