One of the fundamental principles of the BCS is that this suite of in vitro tests are able to detect any in vivo-relevant change in dissolution (e.g. due to a change in manufacturing process type, API particle size etc.), as they encompass the range of pH conditions that can be found in the human GI tract that the dosage form may need to dissolve in (note however that the potential wetting and solubilising effects of bile salts in the small intestine are not evaluated by the BCSdissolution tests).