Be careful as I would never buy these type of things on ebay as there are black market medications and that can be harmful to your dogs. If it is bad the little bit you save may cost you more in a vet bill
I would only get from my vet or drsfosterandsmith.com as I had to buy from there to get clindamyacin tablets and I asked a vet tech whose parents are also vets and she said that she would only by from there and not petmeds.com.
Most major manufacturers only sell to vets