title: Sustained release of aspirin and vitamin C from titanium nanotubes: An experimental and stimulation study.
abstract: Anodization is a promising method to change the topography and wettability of titanium (Ti) implant. The formed TiO2 nanotubes (TiNTs) arrays could enhance the biological properties of Ti implants. In this study, to investigate the possibility of TiNTs arrays on a Ti implant surface as nano-reservoirs for small molecular drugs when using in orthopedic and dental prosthesis, TiNTs on a Ti implant surface were prepared. Then, aspirin and/or vitamin C were loaded into TiNTs as model drugs. Meanwhile, low molecular weight polylactic acid (PLA, Mw=3000) was synthesized and loaded alternately along with aspirin or vitamin C. The release rates of aspirin and vitamin C with/or without PLA loading were investigated by using a UV-Vis spectrometer. The results showed that when loading without PLA, drugs released quickly with presence of burst release. However, when loading with PLA, the cumulative release duration of aspirin and vitamin C was prolonged to over 240h. Molecular dynamics (MD) simulation and dissipative particle dynamics (DPD) simulation results proved that when loading with PLA, PLA molecules aggregated gradually and formed clusters or micelles in these nanotubes. Meanwhile, drug molecules were captured and distributed inside the PLA matrix, which retarding the release of drugs. Only when PLA micelles degrade gradually in body fluid, drugs could be released slowly from nanotubes. These knowledge laid ground basis for the following biological experiments.
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China. Electronic address: yangweihu@cqu.edu.cn.
authors.forename: Weihu
authors.initials: W
authors.lastname: Yang
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China.
authors.forename: Conghui
authors.initials: C
authors.lastname: Deng
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Luo
authors.affiliation: Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China. Electronic address: kaiyong_cai@cqu.edu.cn.
authors.forename: Kaiyong
authors.initials: K
authors.lastname: Cai
mesh_terms: D001205:Ascorbic Acid / Q000737:chemistry / Q000493:pharmacokinetics; D001241:Aspirin / Q000737:chemistry / Q000493:pharmacokinetics; D003692:Delayed-Action Preparations / Q000737:chemistry / Q000493:pharmacokinetics; D056004:Molecular Dynamics Simulation; D043942:Nanotubes / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D003692:Delayed-Action Preparations; D014025:Titanium; D001205:Ascorbic Acid; D001241:Aspirin
keywords: Drug release; Molecular dynamics simulation; Polylactic acid; Small molecule drugs; Titanium nanotubes