Determination of zinc content in insulin products by inductively coupled plasma mass spectrometry

Abstract

Scientific relevance. Zinc content is a quality attribute of insulin products. The State Pharmacopoeia of the Russian Federation requires that it should be determined by flame atomic absorption spectrometry (FAAS). However, many pharmaceutical manufacturers currently prefer inductively coupled plasma mass spectrometry (ICP-MS), which is considered the most promising method for pharmaceutical and biomedical elemental analysis.Aim. The study aimed to develop and validate an ICP-MS-based analytical procedure for zinc content determination in insulin products.Materials and methods. The study focused on human insulin, insulin lispro, insulin aspart, and insulin glargine in the form of active substances, suspensions for subcutaneous injection, and solutions for injection from different manufacturers. Zinc content was determined on an Agilent 7900 ICP-MS; the analysis included 66Zn signal intensity registration.Results. The study compared the results of zinc content determination in test samples with either hydrochloric or nitric acid used as the solvent for sample preparation. The authors selected the experimental conditions to achieve relative standard deviations (RSDs) of not more than 2.5% for the measurements. The ICP-MSbased analytical procedure was validated for its specificity, linearity, accuracy, and precision in the range of 0.4–1.6 mg/L. The authors compared the measurements of zinc content made using FAAS and ICP-MS.Conclusions. The ICP-MS-based analytical procedure for zinc content determination in insulin products meets the validation criteria. This analytical procedure, as developed and validated, may be used in the quality control of medicinal products in the Russian healthcare system and at the batch release stage of pharmaceutical manufacturing.