Spectrofluorimetric and cyclodextrin-enhanced spectrofluorimetric methods for the determination of naphazoline in nasal and eye drops

A spectrofluorimetric method has been developed for the determination of naphazoline based on its fluorescence activity. This method allows the determination of 0.1-3.0 mug ml(-1) naphazoline in aqueous solution with excitation and emission wavelengths at 281 and 330 nm respectively. The complexation between naphazoline and beta-cyclodextrin gives a 1:1 complex. A cyclodextrin-enhanced spectrofluorimetric method has also been developed which has better sensitivity and limit of detection (15 ng ml(-1)) as compared to that in the absence of cyclodextrin. Both methods have been applied satisfactorily to the determination of naphazoline in pharmaceutical preparations.