title: Pharmaceutical solids: a strategic approach to regulatory considerations.
abstract: OBJECTIVE
  This review describes a conceptual approach to the characterization of pharmaceutical solids.
  
  
  METHODS
  Four flow charts are presented: (1) polymorphs, (2) hydrates, (3) desolvated solvates, and (4) amorphous forms.
  
  
  RESULTS
  These flow charts (decision trees) are suggested as tools to develop information on pharmaceutical solids for both scientific and regulatory purposes.
  
  
  CONCLUSIONS
  It is hoped that this review will lead to a more direct approach to the characterization of pharmaceutical solids and ultimately to faster approval of regulatory documents containing information on pharmaceutical solids.
mesh_terms: D055598:Chemical Phenomena; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D002627:Chemistry, Physical; D003663:Decision Trees; D004335:Drug and Narcotic Control; D004364:Pharmaceutical Preparations / Q000737:chemistry*
chemical_list: D004364:Pharmaceutical Preparations