Determination of rizatriptan in its tablet dosage forms by UV spectrophotometric and spectrofluorimetric methods

Rizatriptan is a recently-approved selective 5-HT1B/1D agonist which is used in the treatment of migraine headaches. Two spectrophotometric and a spectrofluorimetric methods have been developed for the determination of rizatriptan in its tablet forms. Rizatriptan in its aqueous solutions was determined at the wavelength ranges of 200-350 nm by the spectrophotometric and of 200-450 nm by the spectrofluorimetric methods. Rizatriptan showed an absorption peak at 225 nm, a first-order derivative signal at 232 nm, a fluorescence emission peak at 362 nm (lambda(ex) = 280 nm). Linearity ranges were found as 0.10-15.00 mug mL(-1) for the UV, 0.05-15.00 mug mL(-1) for the first-order derivative UV spectrophotometric and 0.03-10.00 mug mL(-1) for the spectrofluorimetric methods. Limit of quantitation was determined as 0.1 mug mL(-1) for UV spectrophotometric, 17 ng mL(-1) for first-order derivative UV spectrophotometric and 28 ng mL(-1) for spectrofluorimetric methods whereas limit of detection was calculated as 72 ng mL(-1), 5.6 ng mL(-1) and 8.6 ng mL(-1) for the same measurements, respectively. No interference was found from tablet excipients at the selected wavelengths and assay conditions. Developed methods were found to be validated and showed good precision and reproducibility. Proposed methods were successfully applied to the assay of rizatriptan in pure and tablet dosage forms and assessed as to be simple, rapid, sensitive, accurate and relatively inexpensive.