Design and In Vitro Evaluation of Simvastatin-Hydroxyapatite Coatings by an Electrochemical Process on Titanium Surfaces

The aim of this study was to deposit simvastatin-hydroxyapatite (sim-HA) coatings on titanium surfaces by an electrochemical process and evaluate osteoprogenitor cell responses to sim-HA-coated surfaces. Simvastatin was prepared onto titanium surfaces with varying concentration (10(-7), 10(-6), 10(-5) and 10(-4) mol/L). Surface characteristics were performed by FSEM, XRD and FTIR. LC-MS/MS method was used for simvastatin quantification in Sim-HA-coated surfaces. Murine calvaria-derived pre-osteoblastic cell (MC3T3-E1) proliferation, alkaline phosphatase activity (ALP) and osteocalcin release were used to measure osteoblastic activities. FSEM observation showed rod-like HA crystals covered on all surfaces. As drug concentration increased, the crystal diameter decreased. XRD and FTIR observations showed all coatings consisted of HA. LC-MS/MS test showed the simvastatin concentration in 10(-6) mol/L group was 2.77x10(-7) mol/L/cm(2), while in 10(-7) mol/L group was 1.89x10(-7) mol/L/cm(2). MC3T3-E1 cells grown on 10(-7) mol/L and 10(-6) mol/L Sim-HA surfaces showed increased ALP activity as compared to HA-coated surfaces on day 7 (P < 0.05) while at 10 day, all Sim-HA groups were significantly increased than HA group (P < 0.05). Two Sim-HA groups showed significant increases in osteocalcin production on 7 10 and 14 day (P < 0.05). It showed that incubation with 10(-7) mol/L simvastatin enhanced the cell proliferation to a statistically significant extent (P < 0.05) compared with the HA group at day 7. It was concluded that simvastatin was successfully deposited into HA coatings using the electrochemical process and the sim-HA coatings enhanced differentiation of osteoprogenitor cells.