Development and validation of a green spectrophotometric method for the determination of antiarrhythmic procainamide in injection solution

This study aims to present the spectrophotometric method for the determination of procainamide hydrochloride in its dosage form. It is based on the reaction of procainamide with 1,2-naphthoquinone-4-sulfonic acid (NQS) in alkaline environments, and its maximum light absorption wavelength is 460 nm. Calibration curves and linear regression equations were constructed and computed under optimal conditions. The linear relationships between absorbances and drug concentrations were excellent, with correlation coefficients (0.998) in the range of 1-50µg/ml. The detection level is 0.3 µg/mL. The measured recovery rate ranges from 98.0 to 102.5%. We investigated the optimal conditions and the effects of pH, reaction time, solvent, and foreign ions on procainamide hydrochloride determination. The precision was satisfactory, with relative standard deviation values not exceeding 1.7 %. The assay's accuracy was ≥98.2%. This approach is quick and straightforward, and it can be used to determine the amount of procainamide in a solution for injection. The results acquired by this method matched with those obtained from the official United States Pharmacopeia.