Spectrophotometric determination of citalopram hydrobromide in pharmaceuticals

Abstract

Simple, rapid and sensitive methods are described for the spectrophotometric determination of citalopram hydrobromide (CIT) in pharmaceuticals. The method A is based on the oxidation of citalopram by a known excess of bromate-bromide mixture in hydrochloric acid medium, reduction of the residual oxidant by a fixed amount of iron(II) and the formation of iron(III)-thiocyanate-complex which is measured at 480 nm. In the method B, 1,10-phenanthroline is used as a complexing agent and the formation of iron(II)-1,10-phenanthroline, which is measured at 510 nm. The system obeys Beer's law in the concentration range of 1.0-7.0 μg mL-1 of CIT for method A and 0.6-6.2 μg mL-1 of CIT for method B. No interference observed from common pharmaceutical adjuvants. Both methods are equally precise as shown by the relative standard deviation values less than 2%. The apparent molar absorptivities and Sandell's sensitivity for method A and B are found to be 2.10 × 104 L mol-1 cm-1, 0.019 μg cm-2, 7.30 × 104 L mol-1 cm-1 and 5.5 × 10-3 μg cm-2, respectively. The methods have been successfully applied to the determination of citalopram hydrobromide in pure and dosage forms. © 2010, Sociedad Química de México.