Effects of hydroxyapatite size on the drug release characteristics of drug-containing coatings.

To reduce infections caused by orthopedic implant surgeries, coatings consisting of cefazolin, hydroxyapatite (HA), and chitosan with sustained drug release were deposited on a Ti6Al4V surface by electrophoretic deposition. The effects of incorporating micro- and nano-HA into the coatings on drug adsorption, release, and antimicrobial activity were investigated. The results indicated that the addition of HA particles greatly increased drug adsorption and that the nano-HA particles adsorbed more drug than the micro-HA particles. Furthermore, cefazolin/chitosan coatings had higher drug release rates in the initial stage. After 45 days, approximately 80.2 ± 2.0, 75.4 ± 1.9, and 67.9 ± 2.6 % drug released from cefazolin/chitosan, cefazolin/micro-HA/chitosan, and cefazolin/nano-HA/chitosan coatings, respectively. The release rate of the cefazolin/HA/chitosan coatings increased significantly after 3 days. Nano-HA provided a steadily increasing release, whereas micro-HA resulted in a burst release from the coating. All three coatings showed >90 % antibacterial activity and >10 mm inhibition zone against Staphylococcus aureus. [Display omitted] • Laser-treated Ti6Al4V provided good coating adhesion. • Micro-HA resulted in a burst release from the coating. • Nano-HA provided the coating a steadily increasing release. • Drug-containing coatings had good antibacterial activity against S. aureus. [ABSTRACT FROM AUTHOR]