The Effect of Si-Doping on the Release of Antibiotic from Hydroxyapatite Coatings

Herein, we show that incorporation of ions during biomimetic coating deposition may be utilized to tailor the drug loading capacity of hydroxyapatite (HA) coatings. Pure biomimetic HA (HA-B) and Si-doped equivalents (SiHA-B) where deposited by a biomimetic process onto titanium dioxide covered titanium substrates. The antibiotic Cephalothin was incorporated into the coatings by adsorptive loading and the release was studied in-vitro. SiHA-B coatings exhibited superior drug incorporation capacity compared to pure HA-B coatings, resulting in a drug release profile dominated by an initial 10 min burst effect while a more prolonged 10 hour release was observed from HA-B coatings. The results emphasize the possibility to impact the drug release kinetics from implant coatings by selective doping elements and the use of thin, biomimetic HA-coatings as drug delivery vehicles. Functionalizing metal implants with SiHA-B coatings presents an interesting strategy towards creating synergetic effects through ionand antibiotic release and, hence, contributing both towards preventing post-surgical infections and at the same time enhancing the bone-bonding ability.