BackgroundIn order to obtain biomaterials with controllable physicochemical properties, hybrid biomaterials composed of biocompatible biopolymers and ceramic nanoparticles have attracted interests. In this study, we prepared biopolymer/ceramic hybrids consisting of various natural biopolymers and layered double hydroxide (LDH) ceramic nanoparticles via an electrophoretic method. We studied the structures and controlled-release properties of these materials.Results and discussionX-ray diffraction (XRD) patterns and X-ray absorption spectra (XAS) showed that LDH nanoparticles were formed in a biopolymer hydrogel through electrophoretic reaction. Scanning electron microscopic (SEM) images showed that the ceramic nanoparticles were homogeneously distributed throughout the hydrogel matrix. An antioxidant agent (i.e., ferulic acid) was loaded onto agarose/LDH and gelatin/LDH hybrids, and the time-dependent release of ferulic acid was investigated via high-performance liquid chromatography (HPLC) for kinetic model fitting.ConclusionsBiopolymer/LDH hybrid materials that were prepared by electrophoretic method created a homogeneous composite of two components and possessed controllable drug release properties according to the type of biopolymer.

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We have successfully prepared nanohybrids of biofunctional ferulic acid and layered double hydroxide nanomaterials through reconstruction and exfoliation-reassembly routes. From X-ray diffraction and infrared spectroscopy, both nanohybrids were determined to incorporate ferulic acid molecules in anionic form. Micrsocopic results showed that the nanohybrids had average particle size of 150 nm with plate-like morphology. As the two nanohybridization routes involved crystal disorder and random stacking of layers, the nanohybrids showed slight alteration in z-axis crystallinity and particle size. The zeta potential values of pristine and nanohybrids in deionized water were determined to be positive, while those in cell culture media shifted to negative values. According to the in vitro anticancer activity test on human cervical cancer HeLa cells, it was revealed that nanohybrids showed twice anticancer activity compared with ferulic acid itself. Therefore we could conclude that the nanohybrids of ferulic acid and layered double hydroxide had cellular delivery property of intercalated molecules on cancer cell lines.

The present study was aimed at preparing microemulsion-based hydrogel (MBH) for the skin delivery of itraconazole. Microemulsion prepared with Transcutol as a surfactant, benzyl alcohol as an oil and the mixture of ethanol and phasphatidyl choline (3:2) as a cosurfactant were characterized by solubility, phase diagram, particle size. MBHs were prepared using 0.7 % of xanthan gum (F1-1) or carbopol 940 (F1-2) as gelling agents and characterized by viscosity studies. The in vitro permeation data obtained by using the Franz diffusion cells and hairless mouse skin showed that the optimized microemulsion (F1) consisting of itraconazole (1% w/w), benzyl alcohol (10% w/w), Transcutol (10% w/w) and the mixture of ethanol and phospahtidylcholine (3:2) (10% w/w) and water (49% w/w) showed significant difference in the flux (~1 µg/ cm 2 /h) with their corresponding MBHs (0.25-0.64 µg/cm 2 /h). However, the in vitro skin drug content showed no significant difference between F1 and F1-1, while F1-2 showed significantly low skin drug content. The effect of the amount of drug loading (0.02, 1 and 1.5% w/w) on the optimized MBH (F1-2) showed that the permeation and skin drug content increased with higher drug loading (1.5%). The in vivo study of the optimized MBH (F1-2 with1.5% w/w drug loading) showed that this formulation could be used as a potential topical formulation for itraconazole.

Layered metal hydroxides (LMHs) containing calcium were synthesized by coprecipitation in solution having two different trivalent metal ions, iron and aluminum. Two mixed metal solutions (Ca 2+ /Al3+ and Ca 2+/Fe 3+ = 2/1) were added to sodium hydroxide solution and the final pH was adjusted to ~11.5 and ~13 for CaAl-and CaFe-LMHs. Powder X-ray diffraction (XRD) for the two LMH samples showed well developed (00l) diffractions indicating 2-dimensional crystal structure of the synthesized LMHs. Rietveld refinement of the Xray diffraction pattern, the local structure analysis through X-ray absorption spectroscopy, and thermal analysis also confirmed that the synthesized precipitates show typical structure of LMHs. The chemical formulae, Ca2.04Al1(OH)6(NO3)·5.25H2O and Ca2.01Fe1(OH)6(NO3)·4.75H2O were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Particle morphology and thermal behavior for the synthesized LMHs were examined by field emission scanning electron microscopy and thermogravimetricdifferential scanning calorimetry.