In every drug manufacturing process, controls are mandatory. Thinking about the patient, the goal should be to implement processes that are 100% error free, but that is practically impossible. For example, it is not feasible to unpack, check, and analyse every tablet from a batch to check that no mistake has been overlooked.

In any quantification method of a drug or its active ingredient, the linearity of the calibration line is a crucial criterion for the correctness of the values. The measured values should, in the best case, be directly proportional to the concentration of the analyte in the sample. Most methods have their limits; therefore, you often narrow the measurable range (linear range).