Abstract:

BACKGROUND: It’s the stent coatings, most of which are polymers, that play the role of drug carrying and realize the controlled release of the loaded drugs. But clinical trial demonstrates that the late stent thrombosis associated with polymers and the difficulties in drug release control and integrity maintenance are the main challenges currently.
OBJECTIVE: To prepare a novel organic-inorganic hybrid coating with controllable drug release, strong adhesion and excellent flexibility while lowering the use of polymer.
METHODS: 3,4-Dihydroxy-L-phenylalanine (L-DOPA) modified SiO2-PEG hybrid was prepared by sol-gel technique and dip coated onto 316L stainless steel substrate. Aspirin was chosen as sample drug to elucidate the influence of loading method on the releasing dynamics. The surface morphology was investigated by metalloscope and the aspirin release profile was tested by UV/Vis absorption spectra.
RESULTS AND CONCLUSION: The addition of L-DOPA greatly improved the adhesion of SiO2-PEG coating to the substrate. Cracks and warps were effectively avoided. Compared with the burst release, 75% total loading within 1 hour, of aspirin which was loaded by dipping and diffusion, the introducing of aspirin during the sol-gel process can realize a linear and sustained release within 40 hours. A new experimental organic-inorganic coating material with drug controlled-release can successfully fabricated, L-DOPA bonding and self-crosslinking properties are sufficient to solive poor bonding between coating and substrate, easy cracking and poor flexibility of the coating. Aspirin loaded in the sol-gel process can achieve a linear release in the substrate, avoiding burst release phenomenon.