Kinetic Spectrophotometric Determination of Ranitidine

Two spectrophotometric methods were developed for the determination of ranitidine. The first method wasakineticspectrophotometricmethodbasedonthecatalyticeffectofranitidineonthereactionbetweensodium azide and iodine in an aqueous solution. The calibration graph was linear from 4-24 µg/mL. The drug was determined by measuring the decrease in the absorbance of iodine at 348 nm using a fixed time method. The decrease in the absorbance after 1 minute from the initiation of the reaction was related to the concentration of drug. The detection limit of the procedure was 0.76 g/mL. The proposed procedure was successfully utilized in the determination of the drug in pharmaceutical preparations with mean recovery in the range of 99.83 - 101.16% . The second method is a colorimetric method, which depends on the measurement of absorbances of tris (o-phenanthroline) iron(II) [method 2A] and tris (bipyridyl) iron(II) [method 2B] complexes at 512 nm. The complexes obeyed Beer’s law over the concentration range of 2-16 g/mL and 4-40 g/mL for methods 2A and 2B, respectively. The developed method has been successfully applied for the determination of ranitidine in bulk drugs and pharmaceutical formulations. The common excipients and additives did not interfere in its determination.