A Comprehensive Review on Drug Impurities: Types, Risks, and Analytical Methods

Drug impurities are unwanted substances that may be present in pharmaceutical products, arising from raw materials, manufacturing processes, or degradation over time. These impurities can affect the safety, efficacy, and quality of drugs, posing potential risks to patient health. This review explores the various types of drug impurities, including process-related impurities, degradation products, residual solvents, excipient impurities, and microbiological contaminants. The impact of these impurities on drug toxicity, efficacy, stability, and regulatory compliance is also discussed. Furthermore, the review highlights the regulatory frameworks provided by organizations such as the International Council for Harmonisation (ICH), the United States Pharmacopeia (USP), and the European Medicines Agency (EMA) for controlling and managing impurities in drug products. Advances in analytical techniques such as high-performance liquid chromatography (HPLC), mass spectrometry (MS), and nuclear magnetic resonance (NMR) spectroscopy are examined for impurity detection. Finally, the review emphasizes the importance of quality by design (QbD) and risk-based approaches in minimizing impurity levels and ensuring drug safety. Understanding and managing drug impurities remain crucial in pharmaceutical development to meet regulatory standards and ensure patient safety.