An innovative UV spectrophotometric method for the simultaneous determination of meclizine and pyridoxine in tablets

A straightforward, precise, and rapid UV spectrophotometric method has been developed for the simultaneous determination of meclizine (MEC) and pyridoxine (PYR) in binary mixtures. The approach involved two calibration curves: the first was constructed to quantify PYR directly at 290 nm, while the second was used to calculate the concentration ratio (CR) of the mixture at 230 nm. This second curve was generated by plotting the absorbance ratio (AR) against the concentration ratio (CR = [MEC]/[PYR]). Using the experimentally determined concentration ratio (CRₑₓₚ) and the known PYR concentration, the MEC content was calculated as [MEC] = CRₑₓₚ × [PYR]. The method was validated in accordance with ICH Q2 guidelines and demonstrated reliable and consistent performance. When applied to a pharmaceutical formulation, the results expressed as a percentage of the labeled claim were 100.34% ± 0.47 for MEC and 100.04% ± 0.182 for PYR. Furthermore, statistical comparison with a previously published chromatographic method confirmed the equivalence of the two approaches. These results suggest that the developed method is suitable for routine quality control analysis of pharmaceutical preparations containing MEC and PYR. The linearity ranges were 4-20 µg/mL for meclizine and 6-30 µg/mL for pyridoxine and close to 1.00 for both analytes. Excellent precision was demonstrated, with percent Relative Standard Deviations (RSD%) well below 2%. The method also exhibited high accuracy, with analyte recoveries from tablets formulation 99.62 ± 0.34 and 98.92 ± 0.62 for MEC and PYR, respectively.