Delivery of poorly soluble drugs has been problematic due to its low absorption profile and bioavailability. In this work, ursodeoxycholic acid (UDCA), a poorly-soluble drug, was intercalated into inorganic nanovehicle, layered double hydroxides (LDHs), with a molecular level to enhance its solubility in biological fluid. The UDCA-loaded nanovehicle (i.e., UDCA-LDHs) was also coated with an anionic polymer, Eudragit(®) S100, to increase the dissolution rate of UDCA. According to the powder X-ray diffraction (PXRD) patterns of UDCA-LDHs, the gallery height of LDHs was expanded from 3.6Å to 28.3Å, indicating that the UDCA molecules were successfully intercalated into the interlayer space of LDHs. Fourier transform infrared (FT-IR) spectra also revealed that the UDCA molecules were well stabilized in the LDHs through electrostatic interaction. The in vitro dissolution test in a simulated biological fluid (pH=6.8) showed that the total dissolved fraction of UDCA for the first 2h was about 60.2% for the Eudragit(®) S100 coated UDCA-LDHs, which was a dramatic increase as compared with 19.0% dissolution from intact UDCA. It is, therefore, concluded that LDHs nanovehicle coated with an anionic polymer is a promising delivery system for improving aqueous solubility of poorly soluble drugs.
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