Electrocoating of stainless steel coronary stents for extended release of paclitaxel

Nonbiodegradable polymer coating based on N-(2-carboxyethyl)pyrrole (PPA) and butyl ester of PPA (BuOPy) were successfully electrodeposited on a stainless steel stent surface using cyclic voltammetry. Chemical composition of the coating was examined by X-ray photoelectron spectroscopy. Polymer stability was examined by immersing the coated stent into 1:1 solution of fetal calf serum:seline solution up to 1 year and implantation subcutaneously in mouse for 1 week. Morphology changes were then recorded by scanning electron microscopy. Paclitaxel loading was carried out by immersion into drug solution and its release was detected by HPLC. The results show that thin (single micrometers), uniform coating with various morphology and hydrophobicity can be created by electrochemical deposition. The polymer did not show significant histopathological or morphological changes in vitro and in vivo. The surface properties allow loading appropriate amounts of paclitaxel and release it slowly up to a month.