International Journal of Chemical Studies
Vol. 3, Issue 2 (2015)
Spectrophotometric determination of metoprolol in pharmaceutical formulation by charge transfer complexation
Author(s): Nabil AF Alhemiary, Eman M Shediwa
Abstract: Two simple and selective spectrophotometric methods are described for the determination of metoprolol tartar at as base form metoprolol (MTP) in bulk drug, and in tablets and capsules. The methods are based on the molecular charge transfer complexation of metoprolol base MTP with Bromothymol blue (BTB) or 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The yellow and orange colored radical anions formed on dissociation, are quantitated at 413 nm (BPB method) or 457 nm (DDQ method). The assay conditions were optimized. Beer's law is obeyed in the concentration ranges 2.0-40.0 μg mL-1 in BPB method and 5.0-25.0 μg.mL-1in DDQ method, with respective molar absorptivity values of 5.78 × 103 and 4.05 × 103 L mol-1 cm-1. The reaction stoichiometry in both methods was evaluated by Job’s method of continuous variations and was found to be 1:1 MPT-BPB, MPT-DDQ. The developed methods were successfully applied to the determination of MTP in pure form and commercial tablets with good accuracy and precision. Statistical comparison of the results was performed using Student's t-test and F-ratio at 95% confidence level and the results showed no significant difference between the reference and proposed methods with regard to accuracy and precision. Further, the accuracy and reliability of the methods were confirmed by recovery studies via standard addition technique.
Pages: 24-29 | 1070 Views 12 Downloads
How to cite this article:
Nabil AF Alhemiary, Eman M Shediwa. Spectrophotometric determination of metoprolol in pharmaceutical formulation by charge transfer complexation. Int J Chem Stud 2015;3(2):24-29.