title: Improved dissolution behavior of lipophilic drugs by solid dispersions: the production process as starting point for formulation considerations.
abstract: BACKGROUND
  Many new drug substances have low aqueous solubility which can cause poor bioavailability after oral administration. The application of solid dispersions is a useful method to increase the dissolution rate of these drugs and thereby improve their bioavailability. So far, several methods have been developed to prepare solid dispersions. To obtain a product with the desired attributes, both the formulation and production processes should be considered.
  
  
  METHODS
  The most currently used methods to produce solid dispersions, such as the fusion method, hot melt extrusion, spray drying, freeze drying and supercritical fluid precipitation, are reviewed in this paper. In addition, the physicochemical characteristics of the obtained solid dispersions are discussed.
  
  
  CONCLUSIONS
  Solid dispersions can be successfully prepared by simple fusion, hot melt extrusion, spray drying, freeze drying and supercritical fluid precipitation. Hot melt extrusion, spray drying and freeze drying are processes that can be applied for large scale production. The simple fusion method is not very suitable for large scale production, but is particularly suitable for screening formulations. The most recent method to produce sold dispersions is supercritical fluid precipitation. The process conditions of this method need extensive investigation, in particular in relationship with the selection of the type of carrier and/or solvent. Both processes and formulation aspects strongly affect the characteristics of solid dispersion products. Furthermore, application of crystalline solid dispersions is gaining increasing interest because they are thermodynamically more stable than amorphous solid dispersions.
authors: University of Groningen, Department of Pharmaceutical Technology and Biopharmacy, Groningen, The Netherlands. P.srinarong@rug.nl
authors: Parinda
authors: P
authors: Srinarong
authors: Hans
authors: H
authors: de Waard
authors: Henderik W
authors: HW
authors: Frijlink
authors: Wouter L J
authors: WL
authors: Hinrichs
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D055598:Chemical Phenomena; D002626:Chemistry, Pharmaceutical; D003663:Decision Trees; D004337:Drug Carriers / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D004339:Drug Compounding / Q000379:methods*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D004364:Pharmaceutical Preparations / Q000008:administration & dosage* / Q000737:chemistry*; D014677:Pharmaceutical Vehicles / Q000737:chemistry; D010599:Pharmacokinetics; D012995:Solubility; D013535:Suspensions
chemical_list: D004337:Drug Carriers; D004364:Pharmaceutical Preparations; D014677:Pharmaceutical Vehicles; D013535:Suspensions