Nan,

Your interpretation is correct. But, I wouldn't read too much into it. Temporal variations in plasma concentrations are much smaller than for, say, immediate release levodopa. This is partly because the underlying drug has a longer half-life; partly because of the continuous delivery.

The data in my previous post refers to a one-off application. Normally, you would be in (almost) steady-state where the drug left over from the previous day help to smooth out differences.

Chen et al. [1, Figure 3] show a graph of the steady state concentration against time. Roughly speaking, this shows minimum concentrations 2 hours after a new patch is put on and maximum concentrations, double the minimum levels, platauxing between 16 and 20 hours after the patch was put on. (The same graph also shows differences due to the patch site.)

Regarding the timing of the dose, they write [1]:

"As food does not affect the absorption of transdermal rotigotine, the rotigotine patch can be applied without regard to the timing of meals. On patch application, the mean ± SD total systemically absorbed dose over 24 hours is 46.1 ± 10.6% of the total rotigotine patch content.... Most of the nonsystemically absorbed drug remains in the patch (as opposed to residing in epidermal strata)."

What appears to be the official web site of Neupro states [2]:

"Patients can choose the most convenient time of day or night to apply Neupro® but should be advised to apply the patch at approximately the same time each day. If a patient forgets to change a patch, a new patch should be applied as soon as possible and replaced at the usual time the following day."

References

[1] "Transdermal Rotigotine: A Clinically Innovative Dopamine-receptor Agonist for the Management of Parkinson's Disease"
Jack J. Chen, Pharm.D., FCCP, David M. Swope, M.D., Khashayar Dashtipour, M.D., Ph.D., Kelly E. Lyons, Ph.D.
Pharmacotherapy. 2009;29(12):1452-1467.
http://www.medscape.com/viewarticle/714562_3

[2] http://www.neupro.com/parkinsons-dis...cp/dosing.html

John