Validation of Method for Mercury Impurities Determination in Protamine Sulfate by Stripping Voltammetry

Abstract

Introduction. The article presents the results of the validation of our developed method – stripping voltammetry (SVA) used for mercury impurities determination in protamine sulfate. Procedure was validated in terms of specificity, accuracy, precision (repetability and intermediate precision), and LLOQ. To confirm the results of the SVA method, we choose as comparative analyzes for mercury content determination in protamine sulfate generally accepted methods: atomic absorption spectroscopy (AAS), X-ray fluorescence spectrometry (XRF), and the pharmacopeia method according to the European Pharmacopoeia.Aim. Validation of method developed for mercury impurities determination in protamine sulphate by stripping voltammetry.Materials and methods. Protamine sulfate solution for injection 10 mg/mL (Novosibhimpharm», Novosibirsk, Russia) was used as a study object. The method of stripping voltammetry was performed at TA-4 semi-automatic analyzer (Tomanalit, Tomsk) with VALabTx software included. At the A. V. Nikolaev Institute of Inorganic Chemistry (Institute of Inorganic Chemistry SB RAS) atomic absorption spectroscopy was perfomed. At the Pacific State University was carried out X-ray fluorescence spectrometry. We carried out the pharmacopeia method in conjunction with «Novosibhimpharm» factory.Results and discussion. We validated the developed method for accuracy and precision. We evaluated the repetability by 10 measurements; the coefficient of variation was 7.8. We tested the intermediate precision for six measurements; the coefficient of variation was 7.9 and 7.4 for analyst № 1 and analyst № 2, respectively. According to our methodology, the mercury impurities content in protamine sulfate is 0.03 ppm. We compared our results with other generally accepted methods for the mercury determination in organic objects. When determining mercury by the AAS method, the result was ≤0.5 ppm, with XRF – 0.1 ppm. Pharmacopeia method results cannot be reliable due to the lack of repeatability.Conclusion. We validated the previously developed method for mercury impurities determination in protamine sulfate by stripping voltammetry. The results of our method are comparable with the results of other methods, such as AAS and XRF. That Therefore stripping voltammetry can be used in quality control of protamine drug products.