The Perfect Poison

My brother and I run the poison operations out of the manor Ravenholdt.$B$BLord Ravenholdt tasked me to track down a new and extremely effective poison compound that can be crafted from the venom sacs of the inhabitants of Zul'Gurub and the Ruins of Ahn'Qiraj.$B$BThere are two particularly venomous beasts residing in those blasted ruins that possess what it is that we might be looking for, $c. Bring me a venom sac from the beasts Kurinnaxx and Venoxis and we would be eternally grateful.