Spectrophotometric Determination of Furosemide Using Pyrogallol Reagent in Pharmaceutical Preparations

This research presents a rapid and accurate spectrophotometric method for furosemide determination. This method depended on charge transfer reaction of furosemide with pyrogallol reagent using sodium carbonate. It was observed that a product with a bluish-green color was formed after completing the addition and gave the highest absorption intensity at the wavelength of 610 nm. Following Beer's law, the straight standard curve was obtained in the concentration range of (1-20 µg/mL. The statistical results showed that the method has good accuracy and agreement. The molar absorptivity value was 2.3813×104 l/mol.cm and sensitivity of Sandell's was 0.0138 µg/cm2. The relative standard deviation (RSD%) values ​​ranged from 0.18 to 0.71%, relying on the concentration level. For the furosemide estimation, the suggested method has been successfully applied in its pharmaceutical preparations and pure form.