Challenges and Progress in Related Substance Method Development: A Review of Validation Protocols

Abstract

The detection and quantification of related substances, including impurities and degradation products, are crucial for ensuring the quality and safety of pharmaceutical products. The development of robust analytical methods for related substances has faced numerous challenges, ranging from the complexity of pharmaceutical formulations to stringent regulatory requirements. This review highlights the key hurdles in related substance method development, including issues related to sensitivity, selectivity, and matrix effects, as well as the need for stability-indicating capabilities. It also examines the progress made in the field, particularly through the introduction of advanced chromatographic techniques such as UHPLC and SFC, and the coupling of mass spectrometry for enhanced sensitivity and specificity. The review further explores the role of automated method development and the adoption of standardized validation protocols guided by regulatory frameworks, alongside the application of Quality by Design (QbD) principles to optimize and ensure the robustness of analytical methods. Despite significant advancements, continuous monitoring, revalidation, and adaptation to emerging impurities remain critical for maintaining the reliability of these methods in pharmaceutical quality control.