Catecholamine-Containing Biodegradable Microsphere Implants: An Overview of Experimental Studies in Dopamine-Lesioned Rats

The main neurochemical characteristic of Parkinson’s disease (PD) is a marked lesion of the nigro-striatal dopamine pathway. In attempts to provide dopamine replacement therapy to Parkinson’s patients, the current medication is L-DOPA (Birkmayer and Hornykiewicz, 1961). Dopamine (DA) itself cannot be taken orally because it will not reach the brain. Unfortunately, L-DOPA can cause serious adverse reactions and its effectiveness decreases with time. For these reasons, there has been an increasing demand for and interest in novel techniques for site-directed delivery of substances into the central nervous system (CNS) (Stahl, 1984).