In this article, we’ll learn about multiple requirements/guidelines prescribed by sections 11.17, 11.18, and 11.19 of ICH Q7 to handle primary and secondary reference standards

Learn how to handle other standards including laboratory reagents and standard solutions

Requirements to handle primary reference standards

Section 11.17 of ICHQ7 prescribes primary reference standards that should be obtained as appropriate for the manufacture of APIs. The source of each primary standard must be recorded. Records of each primary reference standards storage and usage should be maintained by the supplier’s recommendations. It is necessary to have primary standards in the QC laboratory for testing and release of materials during manufacturing. The source of such standards has to be documented fully.

The sources generally are from USP or EP. They supply the primary standards as current reference standards (CRS). These primary standards are identified with a specific lot number. For this purpose, you have to visit the respective official website and download the COA. Document this information along with the certificate of analysis. The primary standard gets replaced with fresh slots. There should be a detailed procedure in your sop on handling primary standards. The procedure should describe how frequently the respective website is checked to find out if there is a change in the lot number.

It is necessary to replace the old standard with a new one whenever a new lot is available. Read the usage instructions carefully before using the primary standards. Appropriate storage conditions have to be followed as recommended by the supplier. Some standards may have to be stored at 2 to 8 degrees Celsius or 25 degrees Celsius or in different temperature conditions. Certain standards are hygroscopic and need to be protected from accidental ingress of traces of water unless such standards are stored well protected in a desiccator with active desiccant they can lose their potency. So, it is very important to adhere to the storage conditions as recommended. 

Primary reference standards from an officially acknowledged source are normally used without testing if stored under conditions consistent with the supplier’s recommendations. The official standards are already qualified at the source hence it is not required to test once again. They are well elucidated for chemical structure impurities and purity established fully at the source. However, those sources may not provide us with such data for our records. It will be archived at the source site also the standards will not give complete analytical data on the standard. It gives only information on potency or levels of impurities etc. It's also important that they are stored as recommended to avoid any deterioration.


Section 11.18 prescribes when a primary reference standard is not available from a recognized resource, then an in-house standard should be developed. Appropriate testing should be performed to establish the identity and purity of the primary reference standard. Furthermore, appropriate documentation of this testing should be maintained. This section is important when there is no primary standard available from any of the official sites it is necessary to have an in-house primary standard prepared. 

Let us understand what is a primary standard it is a fully characterized and qualified substance the characterization of a chemical compound is established for its chemical structure. How the functional groups are arranged is molecular weight information on elements like carbon, nitrogen, hydrogen, etc. With this step, the identity of the compound is established.

What is the qualification? The qualification of a compound is established for its purity levels of impurities all these testing details to establish the identity and purity of the compound have to be documented completely. 

Requirements to handle secondary reference standards

Section 11.19 prescribes secondary standards should be appropriately prepared identified tested approved and stored. The suitability must be determined for every batch of secondary standards before use by comparing it with the primary standard. Furthermore, every batch of secondary reference standards must be re-qualified by a written protocol periodically.

A secondary reference standard is an alternative standard to a primary standard there should be a detailed procedure for preparation of the secondary standard, if necessary, the available material may be reprocessed to make it qualify as a standard. The secondary standard prepared should be evaluated against the primary standard this secondary standard may be used for routine analysis. 

The secondary standard has to be re-qualified using the CRS with a frequency that may be once a year. The detailed protocol should be made with the identification of the source material any reprocessing for purifying to meet the standard quality etc. How to be part of the protocol.


Being a certified supplier of analytical reference standards, we have a wide range of primary and secondary reference standards for both API and impurity. This exclusive variety of reference material can be used in several industries including pharmaceutical, beverage, dairy, pulp & paper, wine, and many more. If you are looking for analytical reference standards, contact us to share your requirements for authentic and custom solutions.