The combination of adsorption by functionalized halloysite nanotubes and encapsulation by polyelectrolyte coatings for sustained drug delivery

Abstract

A novel organic–inorganic hybrid nanocomposite was established for the sustained release of an analgesic. Adsorption by functionalized halloysite nanotubes (HNTs) and encapsulation by polyelectrolyte coatings (PECs) via the layer-by-layer (LBL) self-assembly of chitosan (CHI) and sodium alginate (ALG) were combined for the proposed drug delivery. In order to increase loading capacity, HNT lumen enlargement and γ-aminopropyltriethoxysilane (APTES) modification were introduced to manufacture nanocontainers denoted as AHNTs. Ibuprofen (C₁₃H₁₈O₂, IBU) is an active analgesic that was selected as a model drug to evaluate the pharmaceutical properties. Fourier transform infrared spectroscopy, transmission electron microscopy, thermal gravimetric analysis, zeta potential, and high-performance liquid chromatography were performed to characterize the structure and properties of ALG/CHI PECs on AHNTs loaded with IBU (IBU-AHNTs@PECs). The release behavior was investigated by changing the PEC and pH conditions. An enhanced capacity for adsorption (32%) and a sustained-release performance (115 h) of IBU-AHNTs@PECs toward IBU were demonstrated, which followed the power law kinetic model. The proposed combination is expected to provide an important strategy to regulate drug delivery and extend pharmaceutical applications.