Thanks for this.

Jain et al. write:

"These studies revealed that the dopamine can be effectively delivered to the brain by incorporating it into liposomes , and its degradation in circulation can also be protected. The results of liposomal formulation were found to be superior compared to plain levodopa as well as Syndopa."

Note my bold.

And in the meantime, not wishing to wait 10 years for it to come to market, I'll go back to investigating bananas, which have a high dopamine content. (See recent thread.)

[1] "Brain drug delivery system bearing dopamine hydrochloride for effective management of parkinsonism."
Jain NK, Rana AC, Jain SK.
Drug Dev Ind Pharm. 1998 Jul;24(7):671-5.
http://www.ncbi.nlm.nih.gov/pubmed/9876513

John