title: Insights into the role of polymer-surfactant complexes in drug solubilisation/stabilisation during drug release from solid dispersions.
abstract: OBJECTIVE
  To evaluate the role of polymer-surfactant interactions in drug solubilisation/stabilisation during the dissolution of spray-dried solid dispersions and their potential impact on in vivo drug solubilisation and absorption.
  
  
  METHODS
  Dissolution/precipitation tests were performed on spray-dried HPMC-Etravirine solid dispersions to demonstrate the impact of different surfactants on the in vitro performance of the solid dispersions. Interactions between HPMC and bio-relevant and model anionic surfactants (bile salts and SDS respectively) were further characterised using surface tension measurements, fluorescence spectroscopy, DLS and SANS.
  
  
  RESULTS
  Fast and complete dissolution was observed in media containing anionic surfactants with no drug recrystallisation within 4 h. The CMCs of bile salts and SDS were dramatically reduced to lower CACs in the presence of HPMC and Etravirine. The maximum increases of the apparent solubility of Etravirine were with the presence of HPMC and SDS/bile salts. The SANS and DLS results indicated the formation of HPMC-SDS/bile salts complexes which encapsulated/solubilised the drug.
  
  
  CONCLUSIONS
  This study has demonstrated the impact HPMC-anionic surfactant interactions have during the dissolution of non-ionic hydrophilic polymer based solid dispersions and has highlighted the potential relevance of this to a fuller understanding of drug solubilisation/stabilisation in vivo.
authors.affiliation: School of Pharmacy, University of East Anglia, Norwich, Norfolk NR4 7TJ, UK. sheng.qi@uea.ac.uk
authors.forename: Sheng
authors.initials: S
authors.lastname: Qi
authors.forename: Steve
authors.initials: S
authors.lastname: Roser
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Edler
authors.forename: Claudia
authors.initials: C
authors.lastname: Pigliacelli
authors.forename: Madeleine
authors.initials: M
authors.lastname: Rogerson
authors.forename: Ilse
authors.initials: I
authors.lastname: Weuts
authors.forename: Frederic
authors.initials: F
authors.lastname: Van Dycke
authors.forename: Sigrid
authors.initials: S
authors.lastname: Stokbroekx
mesh_terms: D019380:Anti-HIV Agents / Q000008:administration & dosage* / Q000737:chemistry; D001647:Bile Acids and Salts / Q000737:chemistry; D011232:Chemical Precipitation; D004355:Drug Stability; D007785:Lactose / Q000031:analogs & derivatives* / Q000737:chemistry; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D008823:Micelles; D009570:Nitriles; D014677:Pharmaceutical Vehicles / Q000737:chemistry*; D011136:Polysorbates / Q000737:chemistry; D011724:Pyridazines / Q000008:administration & dosage* / Q000737:chemistry; D011743:Pyrimidines; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012995:Solubility; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D019380:Anti-HIV Agents; D001647:Bile Acids and Salts; D008823:Micelles; D009570:Nitriles; D014677:Pharmaceutical Vehicles; D011136:Polysorbates; D011724:Pyridazines; D011743:Pyrimidines; D013501:Surface-Active Agents; C509290:hydroxypropylmethylcellulose-lactose matrix; C451734:etravirine; D012967:Sodium Dodecyl Sulfate; D008747:Methylcellulose; D007785:Lactose