Determination of creatine in the creatine supplements available

Abstract

Introduction: Creatine is a popular supplement with significant benefits for both athletic performance and human health. It may improve brain function, improve exercise performance and speed up muscle growth. Creatine is the number one supplement for enhancing exercise performance in the gym. Objective: The development of fast, accurate, precise, and low-cost analytical methods is important for assessing the purity of oral supplements in health assessment purposes. Materials and Methods: This paper demonstrates on the development and validation of a simple HPLC assay to determine creatine in Over-the-counter products (OTC). An isocratic, reversed-phase HPLC assay, using deionized water (pH 3) as a mobile phase, was validated in deionized water. The lower limit of quantification (LOQ) for the assay was 1.5 mg/L. The inter- and intra-day RSDs as well as accuracy were below 5%. Over-the-counter creatine monohydrate products practiced in this study labeling as 100% creatine monohydrate. Proposed methodology was found to be suitable for the fast assessment of creatine products available in Iranian market. Results: After plotting the calibration curve by the creatine standard at sequential concentrations, the amount of creatine in the unknown samples is measured and expressed as a (% Recovery). Conclusion: Sport supplements are prime targets for adulteration. There is no official regulation for confirmation the label amount of food supplements. Proposed HPLC method was developed simply for creatine assay with no use of ion-pairing agents or gradient performance. Validation criteria including precision, accuracy stability and robustness are in accordance with FDA demands. The results of validation are comparable with others without concerns of ion-pair equilibrium, organic solvents or specific column. Detection of content and label mismatch in some creatine supplements included in this study is worrisome and highlights an urgent need to strengthen the control system in Iran