http://www.ablackhorse.com/store/pc/Petrodex-Enzymatic-Dog-Toothpaste-6-2-Oz-1389p19120.htm

Good deal!   Note this is the 6.2 oz,  not the 2.5 oz,  I prefer to buy direct from the company, instead going through Amazon. 

  For some reason it's hard to find the large size of this product lately.

BTW: MSPCA has an online gift shop  http://www.zazzle.com/mspcaangell/gifts

I recommend the t-shirts!