The drug-eluting film on the electrode array was analyzed by environmental scanning electron microscopy (ESEM).  Before and after coating, ESEM studies revealed that the drug-loaded PLGA coating yielded a smooth covering with an average thickness of 1.02 ± 0.05 μm. 
ESEM
Drug release kinetics was evaluated in a quasi-stationary release model, using high performance liquid chromatography every 24 h for 15 days.



high performance liquid chromatography