Extended levodopa release from a subcutaneously implanted polymer matrix in rats.

It is well recognized that plasma fluctuations resulting from oral levodopa therapy may cause an unstable clinical response in parkinsonian patients. We have therefore developed a slow-release polymer matrix system that can deliver levodopa continuously for extended periods of time (at least 225 days) after subcutaneous implantation in rats. Advantages of this approach include (1) the elimination of levodopa plasma fluctuations and (2) the possibility of reducing the required dose due to constant plasma levels and because the gastrointestinal tract is circumvented. The peripheral implantation of polymer systems containing levodopa, dopamine receptor agonists, or other anti-Parkinson agents may constitute a novel technology of drug delivery to improve the care of patients with Parkinson's disease.