I don't know the answers to the technical questions you pose. All I know is that I have been on Ropinerole from the beginning (4 years?) and I am still evaluated as "mild" by my neurologist in Denver, Dr. Christopher O'Brien. I got in a study group and then was allowed to continue on Ropinerole by means of a compassionate exemption. As far as I am concerned Ropinerole (SmithKline) is a miracle drug and it is supposed to be on the market soon. I will only add that, in order to qualify for my study group (one of many), you could not have been on Sinemet for more than 30 days. Frankly, I believe (without any scientific basis for that opinion) that the problem may lie wih Sinemet and the extent to which it overworks the substantia nigra and eliminates any natural source for dopamine. As I say, I have no scientific basis for that belief.