Electrospinning coating of nanoporous anodic alumina for controlling the drug release: Drug release study and modeling

Local drug delivery system is a promising alternative to conventional methods. Recently, new implants with ordered nanoporous structure have been recommended to improve the local drug delivery performance, one of the favorites is the nanoporous anodic alumina (NAA). For controlling the drug release from NAA, we introduced a novel method by covering the NAA top surface with electrospinning nanofibers including PVDF/PEG. The film thickness and hydrophobicity properties of nanofibers are exploited to control drug release from NAA. The NAA implants were loaded with indole-3-acetic acid (IAA) as a drug model. Comparison of release characteristics of NAA samples with and without electrospinning coating revealed notable alteration in the IAA release profile. Electrospinning coating method can significantly decrease the burst release and prolong the duration of release from nanoporous structures. The behavior of IAA release from electrospinning coated NAA was described by a two-stage mechanism. The release in the first stage was modeled with the zero-order kinetics model, while in the second stage the release was modeled with the first-order kinetics model. The experimental data were fitted to the new model and an excellent agreement between the experimental data and this model was achieved.