Sensitive sequential injection determination of naproxen based on interaction with beta-cyclodextrin.

A sensitive sequential injection analysis (SIA) methodology for the fluorimetric determination of naproxen is proposed. The developed automatic analytical procedure is based on the complexation of naproxen with beta-cyclodextrin (beta-CD) yielding an enhanced fluorimetric signal (lambda(ex)=280nm, lambda(em)=356nm). Linear calibration plots were obtained for naproxen concentrations up to 1x10(-5)moll(-1). The developed methodology exhibited a good precision, with a R.S.D.<2.1% (n=15). The detection limit of the determination was 1.9x10(-7)moll(-1) with a sampling rate of about 70h(-1). The automatic method was applied to the determination of naproxen in pharmaceutical formulations. The obtained results were compared with those furnished by the reference procedure and the relative deviations were lower than 3.6%. No interference was found from the excipients usually used in solid pharmaceutical formulations.