Highly sensitive spectrofluorimetric method for the determination of two antimigraine drugs in their tablets and in biological fluids. Application to content uniformity testing

A highly sensitive and simple spectrofluorimetric method has been developed for the determination of almotriptan malate (ALM) and zolmitriptan (ZOL) in their pharmaceutical preparations. The proposed method is based on the investigation of the fluorescence spectral behavior of the two drugs in aqueous acidic systems. The fluorescence intensity was measured at 360 and 350 nm after excitation at 270 nm for ALM and ZOL, respectively. The fluorescence-concentration plots were rectilinear over the range 0.1-1.2 mu g mL(-1) and 5-40 ng mL(-1), with lower detection limits of 0.03 mu g mL(-1) and 0.70 ng mL(-1) for ALM and ZOL, respectively. The proposed method was successfully applied for the assay of commercial tablets as well as for content uniformity testing. The application of the proposed method was extended to the assay of ZOL in biological fluids. The results were statistically compared to those obtained by comparison methods and were found to be in good agreement.