Having covered qualitative characterization, the panel turns to a different challenge: what changes when the goal shifts to quantifying a main component or impurity rather than simply identifying it. Piotr Alvarez opens by stressing a two-sided requirement—analysts must ensure they are neither inadvertently generating an impurity during sample manipulation, nor inadvertently degrading one away and undercounting it. He distinguishes between analyzing a drug substance, which typically involves a straightforward active pharmaceutical ingredient (API) dilution, and a drug product, which introduces far more variables: injectable formulations, solid forms, and different delivery vehicles all require different approaches, and excipients can meaningfully affect both separation and recovery. Sustained-release formulations, in which the GLP-1 peptide is embedded in polymeric particles, add another layer of complexity to sample preparation and recovery optimization.
