Fluorimetric determination of aminoglycoside antibiotics in pharmaceutical preparations and biological fluids

2-Hydroxyl-1-naphthaldehyde has been utilized as a fluorigenic reagent for the determination of four aminoglycoside antibiotics namely: neomycin, tobramycin, amikacin and kanamycin, in pure form, in some pharmaceutical preparations and in biological fluids. The method is based on the reaction of the reagent with aminoglycosides through their amino groups. The method is thus selective for those aminoglycosides which contain primary amino groups(s). The reaction products exhibit a maximum fluorescence intensity at 434 nm after excitation at 366 nm. A linear relationship was found between the fluorescence intensity and concentration over the range, 0.5 to 5 ug/mL for neomycin and tobramycin, and 0.25 to 4 ug/mL for amikacin and kanamycin. Percentage recoveries range from 99.67% to 100.26% with standard deviations ranging from +/- 1.32 to +/- 1.69, and a limit of detection (S/N=2) of 10 ng/mL for all drugs. The optimum reaction conditions were studied and the results obtained compared favorably with a published fluorimetric method using fluorescamine reagent.