 So this is an explanation to the question of what is a pro-drug. So a pro-drug like Aldova is something that is administered to the patient in the non-active form. So this actually is going to be converted inside the body to the active form, which of course in this case is dopamine. So this Aldova of course is a treatment for Parkinson's patients. And why would you administer, we can think of it though actually if we want to think of it like this, this gets de-carboxylated, so carbon dioxide is removed by dopamine de-carboxylase. So it's also written, of course this is not the preferred way to write it. But of course the two structures are the same and this is dopamine. So why wouldn't you administer just dopamine to these Parkinson's patients? Because dopamine does not cross the blood-brain barrier. So you've got to administer something that will cross the blood-brain barrier and in this case it's Aldova. And once it gets into the brain, carboxylase moves that carbon dioxide, forming dopamine, giving the patients the active form of the drug, thereby allowing them to relieve their symptoms. So that's a pro-drug, something that's administered to the patient that's not the active form of the drug. Okay, are there any questions on that? Pretty straightforward. Okay, thanks a lot guys.