title: Physicochemical principles of controlled release solid dispersion containing a poorly water-soluble drug.
abstract: BACKGROUND
  The aim of this study was to investigate the physicochemical properties of polyethylene oxide (PEO)-based controlled release solid dispersions (CR-SDs) containing aceclofenac, Gelucire 44/14, poloxamer 407 and pH modifier (Na2CO3).
  
  
  RESULTS
  The immediate release solid dispersions containing the pH modifier greatly enhanced the drug dissolution rate to approximately 100%, while the CR-SDs with PEO showed controlled release. A bigger droplet size and a higher surface charge for the CR-SDs were observed compared with the immediate release solid dispersions. The pH modifier played an important role in modulating the release rate of the drug through changes in the drug crystallinity and the hydrogen-bonding interaction, as well as the microenvironmental pH. Near-infrared images revealed a modulation of the PEO concentration to preserve the pH modifier within the system for controlled release of the drug.
  
  
  CONCLUSIONS
  The dissolution process of PEO-based solid dispersions containing a water-insoluble drug was governed by the changing net effect of the microenvironmental pH, the surface charge, the particle size and the release rate of the pH modifier, as well as the function of PEO in controlling drug release.
authors: Bioavailability Control Laboratory, College of Pharmacy, Kangwon National University, Chuncheon 200-701, South Korea.
authors: Thao Truong-Dinh
authors: TT
authors: Tran
authors: Phuong Ha-Lien
authors: PH
authors: Tran
authors: Jisung
authors: J
authors: Lim
authors: Jun Bom
authors: JB
authors: Park
authors: Soon-Kuk
authors: SK
authors: Choi
authors: Beom-Jin
authors: BJ
authors: Lee
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004008:Diclofenac / Q000031:analogs & derivatives* / Q000737:chemistry; D004337:Drug Carriers; D004339:Drug Compounding; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010316:Particle Size; D020442:Poloxamer / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D017693:Sodium Bicarbonate / Q000737:chemistry; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D013499:Surface Properties; D013678:Technology, Pharmaceutical / Q000379:methods; D014867:Water / Q000737:chemistry*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D012997:Solvents; D014867:Water; D020442:Poloxamer; C104509:gelucire 44-14; D004008:Diclofenac; D011092:Polyethylene Glycols; D017693:Sodium Bicarbonate; C056498:aceclofenac