Analytical method development for simultaneous estimation of kojic acid, ascorbic acid and niacinamide in cosmetics...

A novel HPLC method was developed and validated for the concurrent measurement of kojic acid, ascorbic acid, and niacinamide in cosmetic formulations. Using methanol and 0.1% acetic acid gradient elution on a C18 column, the method enables efficient separation and quantification of all three active components within 15 min, markedly improving analytical speed and solvent economy compared to previous approaches. Rigorous method validation demonstrated outstanding precision, specificity, linearity (r2 > 0.99), and robustness were developed in accordance with ICH criteria with the system appropriateness factors, like the tailing factor and theoretical plate count, consistently meeting acceptance criteria. The limits of detection were as low as kojic acid (0.06 µg/mL), niacinamide (0.10 µg/mL), and ascorbic acid (0.15 µg/mL), while percent recoveries for all analytes ranged between 98% and 102% at multiple concentration levels, confirming accuracy. Repeatability and intermediate precision (%RSD < 2%) were upheld across replicate assays, underlining the method's reliability for routine quality control. The unique advantage of this method lies in its simultaneous, rapid assessment of multi-functional vitamins and antioxidants common to cosmetics, streamlining regulatory compliance and product development. This robust protocol provides a practical solution for manufacturers and research laboratories seeking fast, precise, and economical analysis of active ingredients in commercial skincare products.