Because of all the research I've been doing for my sick little Igby, I did run across this product mentioned in a "care" article:

"The Calcium Sandoz is administered in drop form onto the frog's back at the rate of .08 ml per 10 grams of bodyweight (so you'll also need to be able to weigh the animal on a digital scale)." This is administered once a week, but must be prescribed by a vet.

May I ask why you want to supplement other than dusting/spraying?