title: Modeling and monitoring of polymorphic transformations during the drying phase of wet granulation.
abstract: OBJECTIVE
  The purpose of this work was to monitor polymorphic transformations of glycine during the drying phase of a wet granulation and model the polymorphic conversions using a time-based reconciliation model.
  
  
  METHODS
  Near-infrared spectroscopy (NIR) was used for quantitation of polymorphs, and X-ray powder diffraction (XRPD) was used for qualitative analysis of polymorphs.
  
  
  RESULTS
  The data show that the faster the granulation was dried, the more kinetic trapping of the metastable alpha-glycine polymorph, as predicted by reconciliation of the time scales of both the drying rate and the rate of the solution-mediated conversion.
  
  
  CONCLUSIONS
  By knowing basic properties of the drug substance (solubility of the polymorphic forms and the rate of the solution-mediated conversion), processing conditions, such as the drying rate, can be adjusted to anticipate and prevent potential polymorphic transformations.
authors.affiliation: Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana 48908-2091, USA.
authors.forename: Tiffani D
authors.initials: TD
authors.lastname: Davis
authors.forename: Garnet E
authors.initials: GE
authors.lastname: Peck
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Stowell
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Morris
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Byrn
mesh_terms: D002138:Calibration; D002482:Cellulose; D003890:Desiccation; D004339:Drug Compounding / Q000379:methods*; D005079:Excipients; D005998:Glycine / Q000737:chemistry; D008958:Models, Molecular; D015233:Models, Statistical; D008968:Molecular Conformation; D019999:Pharmaceutical Solutions; D011108:Polymers; D011208:Powders; D012995:Solubility
chemical_list: D005079:Excipients; D019999:Pharmaceutical Solutions; D011108:Polymers; D011208:Powders; D002482:Cellulose; C109691:microcrystalline cellulose; D005998:Glycine