Pharmaceutical quality control: the reference standards labyrinth Kumar Jeetendra | December 4, 2019 Dr. Martina Kotthaus, describing the different types of reference standards used by the pharmaceutical industry. Types of pharmaceutical reference standard (RS) In the pharmaceutical area, there are four major types of reference standards: Primary RS Pharmacopoeial RS (for monograph use) Secondary RS Impurity RS Apart from the pharmacopoeial standards, all of the above come with …