title: Determining the critical micelle concentration of a novel lipid-lowering agent, disodium ascorbyl phytostanyl phosphate (FM-VP4), using a fluorescence depolarization procedure.
abstract: The objective of this study was to determine the critical micelle concentration (CMC) of a novel water-soluble plant sterol derivative (FM-VP4) using a fluorescence depolarization method. The CMC was determined by 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence depolarization. Test solutions of various concentrations of sodium dodecylsulphate (SDS) as a positive control or FM-VP4 in water were spiked with 2 microL of 4 mM DPH in tetrahydrofuran (THF) and left overnight to equilibrate in a dark chamber. Fluorescence of each solution was measured at room temperature using a Perseptive Biosystems Cytofluor Series 4000 multi-well plate reader. Fluorescence intensity increases as DPH is incorporated into the hydrophobic core of micelles. Thus, the CMC is the value at which an abrupt increase in intensity is observed. These points were observed at 8 mM and 0.014 mM for SDS and FM-VP4, respectively. Sodium dodecylsulphate was used as a positive control and supports the validity of our results, as the literature values of SDS are reported to be between 8-8.3 mM. The CMC of FM-VP4 is reported to be 0.014 mM.
authors.affiliation: Division of Pharmaceutics and Biopharmaceutics, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada. kwasan@interchange.ubc.ca
authors.forename: Kishor M
authors.initials: KM
authors.lastname: Wasan
authors.forename: Eugene
authors.initials: E
authors.lastname: Choo
authors.forename: Olena
authors.initials: O
authors.lastname: Sivak
authors.forename: Simon
authors.initials: S
authors.lastname: Wallis
authors.forename: Kevin
authors.initials: K
authors.lastname: Letchford
authors.forename: Helen M
authors.initials: HM
authors.lastname: Burt
authors.forename: David J
authors.initials: DJ
authors.lastname: Stewart
authors.forename: Tatjana
authors.initials: T
authors.lastname: Lukic
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D004161:Diphenylhexatriene / Q000737:chemistry*; D005453:Fluorescence; D005663:Furans / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D010840:Phytosterols / Q000737:chemistry*
chemical_list: C445524:FM-VP4 compound; D005663:Furans; D010840:Phytosterols; D004161:Diphenylhexatriene; C018674:tetrahydrofuran