Design, Synthesis and Antifungal Activity of the Novel Water-Soluble Prodrug of Antifungal Triazole CS-758

Abstract

CS-758 was selected as a candidate for clinical trials, but since its water-solubility was insufficient for an injectable formulation, phosphoryl ester prodrugs were designed. In this study, the synthesis and evaluation of these injectable prodrugs are described. Phosphoryl ester 17h was soluble in water, and was stable in both water and in a solid state. 17h was converted to CS-758 in human liver microsome and was also converted to CS-758 in rats after intravenous (i.v.) administration with good conversion speed and efficiency. 17h (i.v.) reduced the viable cell counts in kidneys in a murine hematogenous Candida albicans infection model and in lungs in a murine pulmonary Aspergillus fumigatus infection model, wherein the effects were comparable to or slightly superior to that of CS-758 (per os).