title: Improving powder flow properties of citric acid by crystal hydration.
abstract: 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.
authors.affiliation: Amgen Inc., Materials Science Laboratory, Small Molecule Pharmaceutics, Thousand Oaks, California 91320, USA. sunx0053@umn.edu
authors.forename: Changquan
authors.initials: C
authors.lastname: Sun
mesh_terms: D002626:Chemistry, Pharmaceutical; D019343:Citric Acid / Q000737:chemistry*; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D011208:Powders; D011312:Pressure
chemical_list: D011208:Powders; D019343:Citric Acid