Reference Standards

[syx]

Related to locked topic: Reference Standards.

Dear all,
Could we perform qualification of working standards against valid working standards?
How do we assign expired date for secondary (working) standard?
Thanks in advance.

Best regards,
Siswanto Tanuatmojo

[Sunjay]

Dear Syx,

Ideally it should not be. Whereve possible the pharmocoepeial standards should be used for the qualification of working standards.

However, as a drug product R & D, we find it difficult to procure the Standards from API mfg. (in case of non pharmacopeial product), so in case of in case of non pharmacopeial products, we are initially qualifying them against std given by API mfg and then against the present lot of working standard.

What other s do?

Regards

[syx]

Based on ICH Guidance: Bioanalytical Method Validation, there are 3 types of reference standards: 1) pharmacopoeial (compendial) standards; 2) commercially supplied reference standards obtained from a reputable commercial source; and/or 3) other materials of documented purity custom-synthesized by an analytical laboratory or other noncommercial establishment. If one wants to develop non-compendial new drug products, he/she may use the second or third type.
Secondary standards (working standards) should be characterized against a primary standards. I asked the first question in the emergency case, when the primary standards are not available yet (may due to on delivery status) and our working standards are not enough for analytical run.

[Sunjay]

Dear Syx,

In my opinion the best way is to capture this in ur SOP.

We are keeping a separate vial under control conditions to be used for the standarization of next working standard (in case of non-pharmacopeial products only) and also we are using the materials supplied by reputed mfg like Sigma/Merck/Acros etc. as primary standards.

But yes, this is mentioned in our SOP.

Regards

[syx]

Ensure that USP Reference Standards are stored in their original stoppered containers away from heat and humidity and protected from light. Follow any special label directions. (Use and Storage of USP Reference Standards)

could we store the reference standards (unopened or previously opened) in refrigerator though the label direction said it should be stored in room temperature? is lower storage temperature always ensure the stability of the reference standards?

[Sunjay]

I agree with Syx that lower temp may not always ensures the better stability, but what is the alternative to store at room temperature?

[H.Thomas]

I do not agree. Lower temperature means lower reaction rate, thus longer stability.

Below is a quote from the EU-document "QUALITY CONTROL PROCEDURES FOR PESTICIDE RESIDUES ANALYSIS", Document N° SANCO/10232/2006

[quote]Pesticide standards, calibration solutions, etc.

Identity, purity, and storage of standards

15. “Pureâ€

[agen]

I Agree with H. Thomas. According to WHO "General Guidelines for the establishment, mantainance and distribution of chemical reference substances", storage at about 5ºC, with precautions to prevent humidity absortion, is satisfactory for most chemical reference substances. The recomendation however is not to open the vials before they reach room temperature to prevent ingress of moisture by condensation. I hope it helps.
Regards,

[Bruce Hamilton]

Lower temperature does not guarantee improved storage conditions.

If a standard changes properties ( eg a liquid becomes a solid, some solids precipitate from solution, some headspace gas dissolves in a solution, etc etc ), then the storage conditions may have adversely affected the integrity of the sample. Also, the container may not have been validated for freezer use. I would expect such standards to be labelled as " Do not freeze/refrigerate/etc" but....

For most APIs, freezer temperatures should be acceptable, but you still have to ensure that the supplier has validated the container for those conditions.

My understanding is that you should follow the guidelines for the standard, and if you want to store materials at different conditions, you would be required to show that the changes do not affect the integrity of both the sample and the packaging..

Bruce Hamilton

[syx]

I asked the same question to USP and they do not recommend store the reference standard in a refrigerator if it's labeled store in room temperature... I do not know the reason, but maybe as Mr. Bruce said.
However, I still in doubt where I should store the reference standard that is labeled store in room temperature.