Impurities can affect the dynamic stability of APIs in solution and suspension by affecting nucleation and growth rates. Therefore, the screening for polymorphs using earlier batches of APIs, which may still contain many impurities, could yield different results compared to screening with later, purer batches. In unfortunate cases, significant forms may not be identified during the initial screening. Therefore, it is recommended to repeat the polymorph screening several times for a batch of APIs that reflect the impurity characteristics of the final product manufactured under GMP procedures before market release.