Green analytical spectrophotometric approach for cephalexin quantification using 2,4-dimethylbenzaldehyde condensation reaction

A simple, rapid, selective, precise, and accurate spectrophotometric method was developed for the determination of cephalexin in dosage form and pharmaceutical formulations. This analytical technique is based on condensation reaction of amino group of cephalexin with 2,4-dimethylbenzaldehyde using sulfuric acid. Yellow Schiff base complex will be formed in this experiment. The highest absorbance was obtained at 397 nm for the Schiff base complex. The Beer–Lambert Law was obeyed at 5–45 µg mL −1 concentrations, with R 2 value being 0.993. Molar absorptivity of the product was estimated to be 3.5 × 10 3 L mol −1 cm −1 . Experimental conditions such as reagents concentration, volume, and temperature, which affect the reaction, have been examined and optimized. Limit of detection and limit of quantitation were found to be 1.026 and 3.42 µg mL −1 , respectively. The proposed method demonstrated satisfactory reproducibility, with relative standard deviation of 7.46% ( n = 5). Potential interference from commonly used excipients present in commercial formulations was evaluated and found to be negligible. The greenness of the proposed method was confirmed using Eco-scale, AGREE, and BAGI metrics, demonstrating its environmental sustainability, and method validation was performed through statistical analysis and recovery studies, and the procedure was successfully applied to the quantification of cephalexin in dosage forms and pharmaceutical preparations. The percentage recoveries ranged from 93.80% to 98.34% for dosage forms and from 97.00% to 106.83% for pharmaceutical formulations.