Functionalization of halloysite nanotubes by enlargement and hydrophobicity for sustained release of analgesic

A novel hydrophobic organic–inorganic hybrid nanocomposite was prepared for sustained release of analgesic. Using enlarged halloysite nanotubes (EHNTs) as nanocontainer and organosilane (OS) as the hydrophobic layer, nanocomposite denote as EHNTs@OS was readily prepared with a mild reaction. Then the EHNTs@OS was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, energy dispersive X-ray analysis, and high-performance liquid chromatography. The hydrophobic layer composed of tetraethoxysilane and octyltriethoxysilane made a difference on the wettability of the EHNTs@OS. It was proved that the nanocomposite exhibited excellent hydrophobicity with a water contact angle of 132°. Moreover, an enhanced capacity for adsorption (25%) and the sustained-release performance (100   h) of the EHNTs@OS toward IBU were demonstrated and it followed the power law kinetic model. In conclusion, the drug-release platform explored in this work is suitable for other drugs and shows further comprehensive application prospect.