in vitro and ex vivo
controlled experiments, reductionist (e.g. cell culturing, RATS)
lab rats
studies on metabolism, more severe effects than what would occur in humans
lab mice
easy to modify DNA, similar to rats
swine
used to study organ grafts
primates
closest to humans, studies on diseases, transplants, drug abuse
non clinical studies
no treatment given
doesnt prove cause and effect of a medication