Synthesis and characterization of Zn/Al-LDH@SiO 2 nanohybrid: Intercalation and release behavior of vitamin C.

Layered double hydroxide (LDH) nanoparticles (NPs) have potential applications for the loading and controlled release of drugs. This study investigated the synthesis of Zn/Al-LDH using the co-precipitation and ion-exchange methods, coating with SiO ₂ NPs and precise control of the release of vitamin C (VC). The results showed that more VC could be loaded by ion exchange. The surface of the VC-loaded LDH NPs was coated with SiO ₂ using the sol-gel and physical mixing methods. The structure, surface morphology, drug loading and thermostability were characterized and the drug release profile and release kinetics of the intercalated LDHs were studied. It was found that the SiO ₂ NPs more uniformly coated the LDH surfaces using the sol-gel process than the physical mixing method. The release behavior of VC from the intercalated nanohybrid is well described by the Avrami-Erofe'ev and Elovich models in the slow and fast stages. The sol-gel coated LDH@SiO ₂ nanohybrid system showed sustained drug delivery compared to the physical mixing method. The overall VC release from LDH increased more than 3-fold after coating with SiO ₂ NPs. Taken together, the Zn/Al-LDH@SiO ₂ coated by sol-gel should be considered as a potential sustained-release drug delivery system for VC.
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