You may be able to dissolve it in dimethylsulfoxide (DMSO) as a concentrated stock solution. The solution would then be diluted with sterile growth medium and exposed to the organism. The sensitivity of the organism to DMSO should be tested to see what percentage by volume can be tolerated.

for the preparation of antibiotic stock solution

put the value in following formula 1000/P*V*C where.

P= Potency of antibiotics

V= Volume in ml

C= concentration in (ug/ml)

you can prepare the stock antifungal solution as in the attached table