title: Simultaneous formation and micronization of pharmaceutical cocrystals by rapid expansion of supercritical solutions (RESS).
abstract: OBJECTIVE
  We investigated the RESS process as a means of simultaneous micronization and cocrystallization of a model drug with poor aqueous solubility.
  
  
  METHODS
  1:1 cocrystals of ibuprofen (IBU) and nicotinamide (NA) were produced with a pilot scale unit for RESS processing.IBU and NA were dissolved in scCO2 at 30 MPa and 50°C. After 24 h, the supercritical solution was expanded at a medium CO2 flow rate of 3.8 kg/h during 60 min into an expansion vessel kept at ambient conditions. Cocrystals were identified with DSC, XRD and confocal Raman microscopy (CRM) and further characterized by SEM, specific surface area, wetting ability, solubility and dissolution testing.
  
  
  RESULTS
  Judging by DSC, XRD and CRM, cocrystals with high purity could be produced with the RESS technique. Micronization via RESS was successful, since the specific surface area of RESS cocrystals was increased almost tenfold in comparison to cocrystals produced by slow solvent evaporation. Due to the additional micronization, the mean dissolution time of IBU from RESS cocrystals was decreased.
  
  
  CONCLUSIONS
  RESS cocrystallization offers the advantage of combining micronization and cocrystallization in a single production step. For drugs with dissolution-limited bioavailability, RESS cocrystallization may therefore be a superior approach in comparison to established cocrystallization techniques.
authors.affiliation: Institut für Pharmazeutische Technologie und Biopharmazie, Pharmazeutisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany.
authors.forename: Katrin C
authors.initials: KC
authors.lastname: Müllers
authors.forename: Maria
authors.initials: M
authors.lastname: Paisana
authors.forename: Martin A
authors.initials: MA
authors.lastname: Wahl
mesh_terms: D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D003460:Crystallization / Q000379:methods; D007052:Ibuprofen / Q000138:chemical synthesis*; D009536:Niacinamide / Q000138:chemical synthesis*; D019999:Pharmaceutical Solutions / Q000138:chemical synthesis*; D012995:Solubility; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D019999:Pharmaceutical Solutions; D009536:Niacinamide; D007052:Ibuprofen