Spectrophotometric techniques to determine tranexamic acid: Kinetic studies using ninhydrin and direct measuring using ferric chloride

Two simple and sensitive spectrophotometric methods in ultraviolet and visible region are described for the determination of tranexamic acid in pure form and pharmaceutical preparations. The first method is based on the reaction of the drug with ninhydrin at boiling temperature and by Measuring the increase in absorbance at 575 nm as a function of time. The initial rate, rate constant and fixed time (120 min) procedures were used for constructing the calibration graphs to determine the concentration of the drug, which showed a linear response over the concentration range 16-37 mu g mL(-1) with correlation coefficient r 0.9997, 0.996, 0.9999, LOQ 6.968, 7.138, 2,462 mu gmL(-1) and LOD 2.090, 2.141 and 0.739 mu gmL(-1). respectively. In second method tranexamic acid was reacted with ferric chloride solution, yellowish orange colored chromogen showed at 375 nm showing linearity in the concentration range of 50800 mu g mL(-1) with correlation coefficient r 0.9997, LOQ 6.227 mu gmL(-1) and LOD 1.868 mu gmL(-1). The variables affecting the development of the color were optimized and the developed methods were validated statistically and through recovery studies. These results were also verified by IR and NMR spectroscopy. The proposed methods have been successfully applied to the determination of tranexamic acid in commercial pharmaceutical formulation. (C) 2008 Elsevier B.V. All rights reserved.