Hey Kim..

As I understand, you can't purchase the powder from a store, but you can make Gloria's Powder yourself.  It is one part Boric Acid Powder to 6 parts cornstarch. 

I had my pharmacy special order me a bottle of Boric Acid powder to mix with the cornstarch. Other people have said their pharmacy couldn't order it for them. but that you can purchase Boric Acid from home improvement stores like Lowes or Home Depot.  I have never looked there for it though.

Good Luck to you, I hope this helps.

Becky