biuret impurity has been formed at a level of 2% by HPLC in one of the API molecules. is there any specific purification methods to reduce biuret impurity below detection limit by HPLC??
Yes, reducing biuret impurity from 2% to below the HPLC detection limit in an API is possible—but it requires carefully chosen purification strategies, tailored to the physicochemical properties of both the API and biuret impurity. Here's a detailed response with specific, practical methods:
🎯 Goal: Reduce Biuret Impurity (
Recrystallization serves as the primary technique. Employ a solvent/anti-solvent system (for instance, Ethanol/Water) in which the active pharmaceutical ingredient (API) crystallizes while the polar biuret remains dissolved. It may be necessary to perform multiple recrystallizations.
Chromatography, whether Flash Column or Prep-HPLC, proves to be highly efficient for separation at the laboratory scale; however, it presents challenges when attempting to scale up.
To eliminate surface impurities, wash the final API crystals with a cold, polar solvent such as cold water or methanol as a concluding polishing step.
Examine the underlying cause (for example, elevated reaction temperature) to avert its occurrence in subsequent batches.
Commence with recrystallization, as it represents the most scalable and practical approach for industrial purification.
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