In the absence of high-quality, cost-effective reference materials for impurities, using RRFs - defined as the ratio of the response of an impurity to that of an API - becomes a pragmatic alternative for quantifying impurities in pharmaceuticals. Our new whitepaper draws on expert opinions and regulatory guidance to offer best practice recommendations for using RRFs in impurity quantitation, addressing key pitfalls to avoid, such as inaccurate RRF assignments due to variability in instrument responses.
