The use of Zn-Ti layered double hydroxide interlayer spacing property for low-loading drug and low-dose therapy. Synthesis, characterization and release kinetics study

Abstract

Zn-Ti layered double hydroxide (LDH) with the shortest interlayer d-spacing (6.6–6.8 Å) was used for the first time for controlled release of the standard model drug ibuprofen. We show that the latter could be loaded up to ∼26% (w/w) and report its kinetic release, while indicating possible uses to avoid drug overdose effects and its adaptability for low-dose drug therapy. Nanohybrid Ibup-Zn-Ti-LDH was characterized by PXRD, 13C NMR, TGA, SEM and drug release was controlled in simulated intestinal medium (pH 6.8 phosphate buffer solution (PBS) at 37 °C). The release kinetics showed that ∼2/3 of the loaded drug amount was rapidly released in the first phase, followed by slow long-term release (up to 24 h) which was probably inherent to the short interlayer distance of LDH or could be attributed to the strong interaction between the drug anions and the Zn-Ti host layers due to the high charge density on the layers. The modeling kinetics for the release data indicated that the ibuprofen release process from Ibup-Zn-Ti-LDH was closely in line with the modified second-order and parabolic diffusion models. These results suggest that the Ibup-Zn-Ti-LDH delivery system is controlled by the diffusion of ibuprofen ions into aqueous solutions via an exchange mechanism with phosphate anions. By comparison to LDH with higher d-spacing, the study revealed a clear effect of the short d-spacing of Zn-Ti-LDH nano-composite material.