Spectrofluorimetric method for quantification of citalopram in pharmaceutical preparations and biological fluids through oxidation with Ce(IV)

A sensitive and simple spectrofluorimetric method for the quantification of citalopram in a pure form, in pharmaceutical preparations, and in human blood plasma and urine has been described. The proposed method was based on the oxidation of citalopram by Ce(IV) in acidic media to produce fluorescent Ce(III), and on the subsequent measurement of its fluorescence intensity at 353 nm after excitation at 252 nm. All variables affecting the oxidation of citalopram such as Ce(IV) concentration, the type and concentration of acid, temperature and heating time were studied and optimized. Under the optimized experimental conditions the linear range of concentration versus fluorescence intensity was found to lie between 0.02 and 1.4 g/ml. Limits of detection and quantification were determined to be 6.9·10−3 g/ml and 2.3·10−2 g/ml respectively. Effects of excipients commonly used in the quantification of citalopram have been studied and no interferences were found. The proposed method was successfully applied to determine citalopram in pure form, in pharmaceutical preparations, and in biological fluids. Good recoveries in the ranges of 95.31–101.67%, 88.50–96.67%, and 90.0–96.67% were obtained for the pharmaceutical preparations (tablets), blood plasma, and human urine respectively.