title: Solubilization of flurbiprofen within non-ionic Tween 20 surfactant micelles: a 19F and 1H NMR study.
abstract: The solubilization of the poorly water soluble anti-inflammatory drug flurbiprofen in non-ionic Tween 20 surfactant micellar solutions was studied by both (19)F and (1)H NMR spectroscopy in an acidic environment. These non-destructive techniques allowed us to investigate the effect of temperature cycling in situ. Using (19)F NMR, an increased solubilisation capacity was observed as the temperature increased. This effect became more pronounced above the cloud point, which was reduced by more than 30 degrees C in the presence of an excess of flurbiprofen. Upon clouding, peak splitting was observed in the (19)F spectrum, which indicates that two pools of solubilised flurbiprofen exist that are in slow exchange on the NMR frequency timescale. The clouding and solubilization processes were found to be reversible, albeit with slow kinetics. Based on chemical shift differences of both Tween 20 and flurbiprofen, as well as NOESY experiments, the flurbiprofen was found to be accumulated within the palisade layer of the Tween 20 micelles.
authors: Particle and Interfacial Technology Group, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Gent, Belgium. Pieter.Saveyn@UGent.be
authors: Pieter
authors: P
authors: Saveyn
authors: Ellen
authors: E
authors: Cocquyt
authors: Wuxin
authors: W
authors: Zhu
authors: Davy
authors: D
authors: Sinnaeve
authors: Katrien
authors: K
authors: Haustraete
authors: José C
authors: JC
authors: Martins
authors: Paul
authors: P
authors: Van der Meeren
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry; D005461:Fluorine / Q000737:chemistry; D005480:Flurbiprofen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D015394:Molecular Structure; D011136:Polysorbates / Q000737:chemistry*; D012995:Solubility; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D008823:Micelles; D011136:Polysorbates; D013501:Surface-Active Agents; D005461:Fluorine; D005480:Flurbiprofen