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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 8.6Å to 29.59Å 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 ${\mathrm{\text{NO}}}_3^{-}$ with Ca${}^{2+}$ and Al${}^{3+}$ 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.

Recently, it has been reported that α-tricalcium phosphate (α-TCP) dental cements containing antibiotics can make good results when used over carious dentine. However, the release behavior of antibiotics and Ca from the cement is not clarified. Therefore, the aim of this study is to examine the in vitro release profile of the antibiotic-containing α-TCP cements. Three kinds of antibiotics (Metronidazole, Cefaclor and Ciprofloxacin) were added to two commercially available α-TCP cements. The set cements were immersed in water at 37°C and the released antibiotics and Ca were determined at regular intervals until three months. The release profile of the antibiotic-containing α-TCP cements was depended on the antibiotics added. The release rate of Ciprofloxacin was not so high in the early stage but it tended to elute continuously for three months, though the release of Metronidazole and Cefaclor reached plateaus within one month. The release rates of Ca from the antibiotic-containing α-TCP cements were higher than that from the control. The amounts of Ca released from Type II were higher than that from Type I. These differences in the release profile between Type I and II cements seemed to reflect the setting reaction of these cements.