Method Development and Validation of Vitamin C Formulations Using Zeroth Order UV-visible Spectrophotometry

Abstract

Vitamin C, also known as ascorbic acid (AA), is an antioxidant and one of the essential nutrients and used as a treatment during the COVID-19 pandemic. In this research, an accurate, precise, reproducible, and cost-effective UV-visible spectrophotometric method has been developed based on the International Conference on Harmonization guidelines to determine the AA content of vitamin C in tablet formulations. The method validation study was conducted by evaluating and optimizing parameters such as linearity, range, limit of detection, limit of quantification, repeatability, inter-day precision, accuracy, and stability. A series of standard stock solutions (6 ppm to 18 ppm) was prepared by using HCl as the co-solvent and measuring the absorbance at 242 nm using a double-beam UV-Vis spectrophotometer. The calibration plot of the standard solutions resulted in a linear graph with a correlation coefficient (R2) of 0.9997 which obeyed the Beer’s Law in the selected range. The stability studies confirmed that the samples were stable for up to 7 days in the refrigerator conditions and 3 days in room temperature conditions. The accuracy was tested with the spike recovery method which showed the mean recoveries occurred from 91.15% to 105.23%. In addition, sample analysis was performed using the developed method.