What's your opinion on Replacing animals being tested with life sentenced inmates?

So I read something about the death penalty, and all stuff on rapeist and murderers. I believe some are wrongfully accused and I do believe a person has a right to defend one’s self.
My question is, for those who weren’t wrongfully accused, and those who are in life for murder or something similar or just as bad, putting them in place of our innocent animals? I never understood why people never thought of this. Those who are in for life they can be a huge help to testing stuff. I know animals are tested with cosmetics and hair stuff. I’m talking about simple easy testing such as soap, rashes, allergies. We can test better on people anyways. It might even bring the crime down. I think putting those poor animals through that harsh treatment is just awful. Animals cant speak to you. People can.
So what is your two cents? What do you think? Ever thought of this for punishment?
Replace the animals and the animal research with people. Of course it wouldn’t be stuff that could kill (like I did readers back in High School about research about cancer with rats) stuff like that wouldn’t be right. But like soap and what not. Stuff we can cure.