The methotrexatum (MTX) was intercalated into the layered double hydroxides (LDHs) to form the MTX/LDH compounds, by the coprecipitation method in the alcohol-water mixed solvent (alcohol-water co-precipitation for short) and NaOH as precipitator. The influence of alcohol-water solvent on the structure of MTX/LDH compounds was systematically investigated by X-ray diffraction (XRD), transmission electron micrograph (TEM), fourier transform infrared spectroscopy (FTIR) and differential thermal analysis (DTA) techniques. The studies indicated that compared with the conventional coprecipitation method in water solvent, the morphology of the particles prepared by the alcohol-water coprecipitation was spherical shape with smaller size and had a good dispersion. MTX anions were intercalated into the LDH sheets as a delined monolayer and the declined angles changed with the variation of the volume ratio of ethanol to water. Our results showed that when the volume ratio of alcohol to water was 1∶3, the particles are the smallest and uniform without agglomeration. At last, the drug release rates with different particles size were studied in phosphate buffer and it showed that the smaller MTX/LDH nanoparticles have the longer release time than those of the larger ones.

Key words: layered double hydroxides, alcohol-aqueous coprecipitation method, methotrexatum, nanocompounds, in vitro release