The Structure and Release Kinetics of Ca–Al Layered Double Hydroxide by Intercalating with Diclofenac Sodium

Abstract

Diclofenac sodium (DS) is an aryl acetic acid nonsteroidal anti-inflammatory drug which is widely used in various types of chronic bone and joint pains, but its terminal plasma half life is short, often accompanied with gastrointestinal side effects. We try to find an inexpensive and effective drug carrier to prolong the administration interval, maintain a stable blood concentration and reduce side effects. In our work, DS had been intercalated into a layered inorganic host, Ca–Al layered double hydroxide (LDH) by co-precipitation under a nitrogen atmosphere to control the release. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscope (TEM) were used to investigate the change of chemical structure and morphological structure when DS was inserted into the interlayer of LDH. X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) were employed to characterize the electron binding energy of calcium and aluminum cations both on the surface and in the bulk of the samples. The results of absorption peaks, morphologies and the basal spacing increased from 8.6[Formula: see text]Å to 29.59[Formula: see text]Å gave the evidences for the intercalation of DS into the interlayer of CaAl-LDH. The results of XPS and XANES spectra revealed the complexation of –OH and [Formula: see text] with Ca[Formula: see text] and Al[Formula: see text] were both were affected by the loading of DS with CaAl-LDH, but no new chemical bonds were formed. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis showed the dissolving process of Ca and Al ions from CaAl-LDH in the solution. In addition, the results of the drug release profile and release kinetic of intercalated LDHs showed that release behavior of DS from intercalated compounds was well controlled.