Phosphorimetric determination of Carvedilol and Telmisartan in pharmaceutical tablet forms

Room temperature phosphorescence methods were developed for the determination of carvedilol and telmisartan in pharmaceutical tablets. This methodology is based on the direct measurements of RTP emission of analytes from their aqueous solutions. Potassium iodide and sodium sulphite were used as heavy atom perturber and oxygen scavenger respectively. The excitation and emission maximum wavelengths were 323 nm and 440 nm for carvedilol and 306 nm and 500 nm for telmisartan. The linear relation was obtained between the relative phosphorescence intensity and concentration of carvedilol and telmisartan in the range of 0.05-2.0 mg/L for both drugs. The limit of detection and the limit of quantitation for carvedilol and telmisartan were found as 0.013 and 0.044 mg/l and 0.0019 and 0.0064 mg/l, respectively. The relative standard deviations of carvedilol and telmisartan are in the range of 1.0-3.5 %. The suggested methods have been successfully applied to the determination of carvedilol and telmisartan in pharmaceutical tablet forms. The results were compared to those obtained with HPLC-UV method.Keywords : Carvedilol, Telmisartan, Phosphorescence, Heavy Atom, HPLC.