Topic overview

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Compatibility means avoiding detrimental physical or chemical interactions between an excipient, the API, and other excipients over the product’s shelf life. Key degradation pathways include hydrolysis, oxidation, Maillard reactions, acid–base interactions, and changes in crystal or solvate form. Potential risks include peroxides in some excipients, reducing sugars with amine-containing drugs, and interactions involving trace metals. Screening tools such as DSC, FTIR, and HPLC can help identify possible incompatibilities; confirmatory stability studies assess whether concerns matter under defined storage conditions. Risk reduction may involve controlling moisture and pH, selecting suitable excipient grades, using antioxidants or chelators where appropriate, and checking interactions with packaging. Excipient shelf life, impurity specifications, storage, and quality considerations are also part of a sound compatibility assessment.