title: Controlled Electrostatic Self-Assembly of Ibuprofen-Cationic Dextran Nanoconjugates Prepared by low Energy Green Process - a Novel Delivery Tool for Poorly Soluble Drugs.
abstract: OBJECTIVE
  The direct effect of electrostatic interaction between ibuprofen and cationic dextran on the system-specific physicochemical parameters and intrinsic dissolution characteristics of ibuprofen was evaluated in order to develop drug-polymer nanoconjugate as a delivery strategy for poorly soluble drugs.
  
  
  METHODS
  Amorphous ibuprofen-DEAE dextran (Ddex) nanoconjugate was prepared using a low energy, controlled amphiphile-polyelectrolyte electrostatic self-assembly technique optimized by ibuprofen critical solubility and Ddex charge screening. Physicochemical characteristics of the nanoconjugates were evaluated using FTIR, DSC, TGA, NMR and SEM relative to pure ibuprofen. The in vitro release profiles and mechanism of ibuprofen release were determined using mathematical models including zero and first order kinetics; Higuchi; Hixson-Crowell and Korsmeyer-Peppas.
  
  
  RESULTS
  Electrostatic interaction between ibuprofen and Ddex was confirmed with FT-IR, (1)H NMR and (13)C NMR spectroscopy. The broad and diffused DSC peaks of the nanoconjugate as well as the disappearance of ibuprofen melting peak provided evidence for their highly amorphous state. Low concentrations of Ddex up to 1.0 × 10(-6) g/dm(3) enhanced dissolution of ibuprofen to a maximum of 81.32% beyond which retardation occurred steadily. Multiple release mechanisms including diffusion; discrete drug dissolution; anomalous transport and super case II transport were noted.
  
  
  CONCLUSIONS
  Controlled assembly of ibuprofen and Ddex produced a novel formulation with potential extended drug release dictated by Ddex concentration.
authors.affiliation: Leicester School of Pharmacy, De Montfort University, The Gateway, Leicester, LE1 9BH, UK, aabioye@dmu.ac.uk.
authors.forename: Amos Olusegun
authors.initials: AO
authors.lastname: Abioye
authors.forename: Adeola
authors.initials: A
authors.lastname: Kola-Mustapha
mesh_terms: D002152:Calorimetry, Differential Scanning; D002412:Cations; D002626:Chemistry, Pharmaceutical; D003637:DEAE-Dextran / Q000737:chemistry*; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D055772:Green Chemistry Technology; D007052:Ibuprofen / Q000737:chemistry*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles; D036103:Nanotechnology; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D013678:Technology, Pharmaceutical / Q000379:methods*; D013818:Thermogravimetry
chemical_list: D002412:Cations; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D003637:DEAE-Dextran; D007052:Ibuprofen