a simple spectrophotometric method for the determination of famotidine via reaction with alizarin red s

a simple, quick, and sensitive spectrophotometric method was proposed to determine famotidine (famt) in its pure form and pharmaceutical preparation (tablet). the method involves the reaction of famt with alizarin red s to produce a stable, water-soluble red complex with the maximum absorption signal at 528 nm, beer’s law is followed for standard famt solutions in the range of 6.0-80 µg/ml with a negative deviation at concentrations higher than 80 µg/ml. the method is sensitive. the molar absorptivity and sandell᾽s sensitivity index values are 3.3 × 10 4 l/mol.cm and 0.0109 µg /cm2 respectively. two approaches were applied to determine the amount of famt in its pharmaceutical formulation (famosam tablets), the one depending on a regression equation and the second on the standard addition method. the results were obtained with sufficient precision and accuracy, with negligible effects from excipient interference.