A simple and selective colorimetric method was developed for the quantification of aminocaproic acid (ACA) in bulk and pharmaceutical formulations. The method was based on the coupling of ACA with ascorbic acid to give a colored product having analytically useful maxima at 390 and 530 nm. The factors; which are mainly concentration of ascorbic acid and heating time; affecting the color development were optimized and incorporated in the procedure. Regression analysis of Beer's plot showed good correlation (r=0.999) in a concentration range of 4-20 μg/mL. The molar absorptivity of the reaction product was 2492.6 L mole cm-1. The limit of detection was 0.86 μg/mL and 0.29 μg/mL at 390 nm and 530 nm respectively. The average recovery for the commercial preparation (Aminocaproic acid injections, 250 mg/ 20 mL) was 108.23±1.45% (n=3) which reflected no interference by the injection excipients. Based on the molar ratio, the reaction stoichiometry was found to be 1:1.
Colorimetric method, Aminocaproic acid, Ascorbic acid