Background: Ursodeoxycholic acid, usually used to dissolve cholesterol gallstones in clinic,
is a typical hydrophobic drug with poor oral bioavailability due to dissolution rate-limited performance.
The objective of this study was to increase the dissolution of ursodeoxycholic acid by amorphous
Methods: Nanoprecipitation based on acid-base neutralization was used to prepare the nanosuspensions
with central composite design to optimize the formula. The nanosuspensions were characterized
by particle size, morphology, crystallology and dissolution.
Results: The ursodeoxycholic acid nanosuspensions showed mean particle size around 380 nm with
polydispersion index value about 0.25. Scanning electron microscope observed high coverage of
HPMC-E50 onto the surface of the nanosuspensions. Differential scanning calorimetry and powder
X-ray diffractometry revealed amorphous structure of the ursodeoxycholic acid nanosuspensions. A
significant increase of dissolution in acidic media was achieved by the amorphous nanosuspensions
compared with the physical mixture.
Conclusion: It can be predicted that the amorphous nanosuspensions show great potential in improving
the oral bioavailability of ursodeoxycholic acid.