COMPARATIVE QUALITY EVALUATION OF COMMERCIAL VITAMIN C SUPPLEMENTS USING UV–VISIBLE SPECTROPHOTOMETRY

Abstract

Vitamin C (ascorbic acid) is an essential water-soluble vitamin widely used as a nutritional supplement due to its antioxidant properties and its role in collagen synthesis and immune function. Since numerous vitamin C formulations are available in the pharmaceutical market, evaluation of their quality is important to ensure safety and therapeutic effectiveness. The present study aimed to compare the quality of different commercially available vitamin C tablets using UV–Visible spectrophotometric analysis and standard pharmaceutical quality control tests. Five brands of vitamin C tablets containing 250 mg of ascorbic acid were evaluated for weight variation, hardness, friability, and assay determination. Quantitative estimation of ascorbic acid was performed using UV–Visible spectrophotometry at 295 nm. The calibration curve showed a linear relationship between concentration and absorbance with an R² value close to 0.999. The assay results indicated that the vitamin C content ranged from 95.89% to 99.51% of the labeled amount. Most brands complied with pharmacopeial limits for weight variation and friability, although minor variations were observed in hardness and mechanical properties. The results suggest that the tested vitamin C supplements generally meet acceptable quality standards. Continuous post-market evaluation is necessary to ensure consistency, safety, and efficacy of pharmaceutical supplements.