Improving powder flow properties of citric acid by crystal hydration.

@article{Sun2009ImprovingPF,
  title={Improving powder flow properties of citric acid by crystal hydration.},
  author={Changquan Calvin Sun},
  journal={Journal of pharmaceutical sciences},
  year={2009},
  volume={98 5},
  pages={1744-9}
}
A batch of poorly flowing citric acid anhydrate was exposed to 69.9% relative humidity to prepare pure monohydrate with nearly identical particle size and morphology but different surface properties. Flow properties of the powders were tested using a ring shear cell. Results show the hydration can significantly improve flow properties of anhydrous citric acid.