This will be an open label study in two parts. In the first part, F901318 (dose 2 mg/kg IV over 4 hours, Day 1) will be followed by F901318 (2 mg/kg IV over 4 hours) given on Day 8, after dosing with fluconazole 800 mg daily for 1 day (Day 4) and 400 mg daily orally for 4 days (Days 5 to 8). Up to twenty subjects will be included in two cohorts which will undergo the same dosing schedules of fluconazole and F901318 and undergo the same procedures. The first cohort will consist of 12 subjects studied in two groups of six subjects each. If there is clearly a difference in F901318 kinetics detectable before and after dosing with fluconazole in this first cohort, the second cohort will not be studied. If there is no clear difference, the second cohort will also be studied to give a final result. In this cohort, based on the pharmacokinetic findings in cohort 1, the dose of F901318 may be increased to up to 4 mg/kg to establish a dose suitable for phase 2 evaluation. PK sampling for plasma F901318 will continue from before the first dose up to and including 72 hours after dosing. PK sampling for fluconazole will continue from before the first dose and up to 72 hours after the fifth dose. A follow up visit will be conducted 7 +/- 2 days after discharge from the clinical unit following completion of blood sampling following the second dose of F901318 and the fifth dose of fluconazole.