Abstract

Novel, simple, and accurate spectrophotometric techniques, i.e., the Q-ratio method and absorptivity factor method were developed to simultaneously estimate Diltiazem and Naringin in a synthetic mixture. In the Q-ratio method, the analytical wavelengths used for the estimation of two drugs were 257 and 275 nm. The method was based on the measurement of absorbance at two different wavelengths, one of which is taken as the λmax of naringin and the other from the isoabsorptive point discovered by overlapping the spectra of two drugs. Whereas for the absorptivity factor method, the analytical wavelengths used were the absorptivity factor points, i.e., 229 and 247 nm obtained after overlapping the spectra of Diltiazem and Naringin at different concentrations. For both methods, methanol was used as a solvent. In these two developed and validated methods, the correlation coefficient observed for linearity was near 1, and the % RSD for precision was less than 2%. All other validation parameters conducted passed the criteria set forth in the International Conference on Harmonization guidelines. Therefore, these techniques can be successfully used for routine quality control tests.

Key words: Diltiazem, Naringin, Q-ratio method, Absorptivity factor method.