Spectrophotometric determination of fluoxetine and sertraline using chloranil, 2, 3 dichloro-5, 6 dicyano benzoquinone and iodine

Spectrophotometric procedures are presented for the determination of two co mmonly used antidepressant drugs, fluoxetine (I) and sertraline hydrochlori de (II). The methods are based mainly on charge transfer complexation react ion of these drugs with either pi accepters chloranil and 2, 3 dichloro-5, 6-dicyanoquinone (DDQ) or sigma acceptor iodine. The colored products are q uantified spectrophotometrically at 550, 450 and 263 nm for fluoxetine and at 450, 455 and 290 nm for sertraline in chloranil, DDQ and iodine methods, respectively. The molar combining ratio and the optimum assay conditions w ere studied. The methods determine the cited drugs in concentration ranges of 80-640, 16-112 and 7.5-60 mu g/ml with mean percentage recoveries of 99. 83, 99.76 and 100.00% and R.S.D. of 1.24, 0.95 and 1.13% in fluoxetine and ranges of 16-160, 15-105 and 6-48 mu g/ml with mean percentage recoveries o f 100.39, 99.78 and 99.69% and R.S.D. of 1.02, 0.81 and 0.57% in sertraline for chloranil, DDQ and iodine methods, respectively. A more detailed inves tigation of the complex formed was made with respect to its composition, as sociation constant K-c(AD), molar absorptivity xi(A)(AD) and free energy ch ange Delta G. The proposed methods were applied successfully to the determi nation of the cited drugs either in pure or dosage forms with good accuracy and precision. The results were compared statistically with those given by the reported methods. (C) 1999 Elsevier Science B.V. All rights reserved.