Section 8.4 states, “Where physical attributes of the API are critical, APIs intended for use in solid
oral dosage forms or suspensions, the blending operation should be validated to show
homogeneity of the combined batch. Validation should include testing of critical attributes (e.g.,
particle size distribution, bulk density, and tap density) that may be affected by the blending
process”. If it is for a liquid, it’s generally not an issue. But, if you know it’s going for a solid oral
dosage form or a suspension, those physical attributes could be critical to the performance of the
drug product.
