SIMPLE AND RAPID SPECTROPHOTOMETRIC DETERMINATION OF ATENOLOL AND ESMOLOL β-BLOCKERS IN PHARMACEUTICAL FORMULATIONS AND SPIKED WATER SAMPLES

Atenolol and esmolol drugs belonging to a β–blocker group are frequently used for the treatment of cardiovascular diseases. These drugs are also charged as water pollutants. A new simple and rapid spectro-photometric method has been developed for their determination in pharmaceutical formulations and in spiked water samples. The proposed method is based on the derivatization of the amino function present in these drugs to the corresponding yellow copper (I) drug dithiocarbamate derivative through reaction with carbon disulphide, pyridine and copper (I) perchlorate in aqueous acetonitrile. The analysis is accomplished for their determination in pharmaceutical formulations by measuring absorbance at 425 nm for atenolol and 420 nm for esmolol. For the determination of these drugs in spiked water samples, the coloured complex is extracted into chloroform and the absorbance of the chloroform extracts is measured at 415 nm and 410 nm for atenolol and esmolol respectively. Linear correlation is obtained in the range 1.00 – 22.00 and 1.50 – 25.00 µg mL^-1 with detection limits of 0.10 and 0.15µg mL^-1 for atenolol and esmolol respectively. The proposed methods show good recoveries of atenolol and esmolol from pharmaceutical formulations and spiked water samples and are in the ranges from 99.00 -100.40% and 98.20 – 100.80% respectively. The 1:1 stoichiometry of the colour reaction between drug as dithiocarbamate derivative and copper (I) perchlorate has been established by photometric titrations. The latter also provides an alternative method for the determination of above drugs in pharmaceutical formulations.