Since apomorphine actually reveals high efficacy in treatment of Parkinson'
s disease but only has a very short half life, it is of only limited clinic
al significance. To overcome this substantial disadvantage, drug applicatio
n by long term delivery systems could be one possibility. Based on this bac
kground, ethylene vinyl acetate polymeric delivery systems were manufacture
d that differed in size, with either coated or uncoated surfaces, but were
similar in apomorphine loading. Release from uncoated polymeric delivery sy
stems followed first order kinetics, whereas coated polymeric delivery syst
ems showed within the first 40 days a period of first order kinetics releas
e, in which the release rate is approximately half that of the uncoated pol
ymeric delivery systems, followed by a zero order kinetics release for more
than 130 days with a daily release rate of 3.1 +/- 0.2 mg. In vivo release
was investigated by determining plasma apomorphine concentrations after im
planting polymeric delivery systems into the abdominal cavities of rats. An
imals with uncoated polymeric delivery systems exhibited symptoms of an apo
morphin overdosage within 20 days after surgery. Using coated polymeric del
ivery systems, a steady state plasma concentration of 15 ng/ml was observed
, which was maintained over a period of 130 days after an initial period of
high plasma concentrations. Based on our results, it is concluded that pol
ymeric delivery systems might be an appropriate method for applying apomorp
hine for the treatment of Parkinson's disease.