I just did a search. You might want to call these people.
You WILL need to know how many doses are in that bottle...there has to be a number of either doses...or the total amount of ml.
Veterinary Compounding - Pharmacy Compounding Specialties
I also found this.....might give you some good info about online pharmacies:
The Scoop about Online Veterinary Compounding Pharmacies | Blogs about Dogs, Cats and Pets | Petside.com