Fluorescence determination of sulphobutylether-β-cyclodextrin in human plasma by size exclusion chromatography with inclusion complex formation

A selective method for the determination of sulphobutylether-beta-cyclodextrin (SBECD) in human plasma has been developed and validated over the range 4-200 mu g ml(-1). SBECD is extracted from plasma using end-capped cyclohexyl solid phase extraction cartridges. This is followed by high performance size exclusion chromatography with a mobile phase consisting of 1-naphthol (0.1 mM) in methanol-potassium nitrate (0.2 M) (1:9 v/v), 1 mi min(-1). The high aqueous content of the mobile phase quenches the fluorescence of 1-naphthol. However, the naphthol forms an inclusion complex with SBECD. The non-polar 'bucket' environment of the inclusion region restores the fluorescence, which is measured at excitation and emission wavelengths of 290 and 360 nm, respectively, when SBECD elutes from the column. (C) 2000 Elsevier Science B.V. All rights reserved.