Fluorescence determination of sulphobutylether-beta-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 microg 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 ml 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.