Displaying 11 results of Sapropterin Impurities Sapropterin is a synthetic form of a natural compound called tetrahydrobiopterin (BH4) which is used to treat certain genetic disorders. However, during the manufacturing process, impurities may be present in the final product. These impurities can affect the quality, purity, and safety of the drug, which is why it is important to monitor and control their levels. Some of the potential impurities that can be found in sapropterin include related substances, residual solvents, and heavy metals. Regular testing and analysis are necessary to ensure that the drug is safe and effective for patients.