Finding out Sporanox's Antifungal Activity

I am going to conduct a study that uses paper disc diffusion method in validating antifungal activity.
Part of my method is to record the antifungal activity of the drug Sporanox (generic name: Itraconazole). I am planning to get the powder inside the capsule. problem is, I don't know where i can dissolve the powder into. so that i could have an itraconazole solution in which i could soak my paper discs there. the preferable concentration is 8micrograms per milliliter. How do I get this solution, will i just dilute the powder in distilled water and soak the paper discs in? or is there a much more precise and reliable way? help me please. I'm hoping for your answers thanks!