Doxycycline Release of Dental Implants With Nanotube Surface, Coated With Poly Lactic-Co-Glycolic Acid for Extended pH-controlled Drug Delivery
When dental implants become infected, the progression of the disease is rapid. Commercially available dental implant surfaces can be easily contaminated, resulting in rapid progression of peri-mucositis and peri-implantitis. The aim of this study was to evaluate, in vitro, the pattern of doxycycline release from by dental implants with titanium nanotube surface (DINS) at different pHs to examine novel drug loading and chemical coating techniques. Nine DINS were loaded with doxycycline and subsequently coated with polylactic-co-glycolic acid (PLGA). High-performance liquid chromatography (HPLC) was used to measure the amounts of released doxycycline in a 30-day period. Cytotoxicity of the DINS was evaluated by an assay using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT). The results showed that the experimental DINS coated with doxycycline and PLGA showed a mean drug release during the experimental period for the groups: pH 7.4 (8.39 μg/mL), pH 6.4 (8.63 μg/mL). The pH 5.4 (15.18 μl/mL) doxycycline release from DINS was faster at pH 5.4 than those at pHs 6.4 and 7.4 (P = .0031 and .0034, respectively). This new surface treatment of dental implants with titanium nanotubes and subsequent drug loading demonstrated biocompatibility and sustained doxycycline release over a 30-day period. Additional studies are needed in order to adopt a stable drug release at neutral pH environment while warranting a constant drug release in an acidic pH environment.

Scanning electron microscopy of a DINS at ×20 000 magnification.

Figure 2. Calibration curve of the standard solutions used for high-performance liquid chromatography (HPLC) analysis. Integrated areas of HPLC peaks were graphed as a function of doxycycline concentration in standard solutions (x-axis). Figure 3. Effect of doxycycline release over time. Note the statistically significant difference at pH 5.4 compared with pHs 6.4 and 7.4. Figure 4. Thirty-day cumulative average quantity (μg) of doxycycline released under pH 5.4, 6.4, and 7.4.

Figure 5. Scanning electron microscopy of a commercially available implant coated with polylactic-co-glycolic acid coating at ×25 magnification. Figure 6. Scanning electron microscopy of a commercially available implant coated with polylactic-co-glycolic acid coating at ×50 magnification. Figure 7. Scanning electron microscopy of a commercially available implant coated with poly lactic-co-glycolic acid coating at ×500 magnification.
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