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Welcome to the frequently asked questions page for BP reference standards.

Did you know... BPCRS are considered to be Primary Standards. They are established by absolute methods and the declared content figures are determined without reliance on comparison to another substance.

Frequently asked questions:

 Q.  How can I place an order for a BPCRS?

A.  Please see the “How to order BPCRS” and “Information” pages of the website. Full terms of trade are available on the information page.

Q.  How do I pay for my BPCRS?

A.  You can pay by credit card, bank transfer or cheque (made payable to MHRA).

Q.  I would like to order a controlled drug. What documentation do I need?

A.  It is your responsibility to obtain any licences or other relevant documentation to comply with the laws of the importing country.

Schedule 1 to 5 Controlled Drugs (narcotics):

Category 1 Substances (precursor chemicals):

For all applications, the name and address of the Exporter must be as follows:
British Pharmacopoeia Commission Laboratory, Queens Road, Teddington, Middlesex TW11 0LY

Q.  Who should I make my cheque payable to?

A.  All cheques MUST be made payable to MHRA.
We regret that we cannot accept cheques payable to any other name and these will be returned to you.

Q.  There is a reference standard mentioned in a BP monograph but I can't find it in the BPCRS catalogue. Where can I buy this standard?

A.  If the reference standard is followed by the letters CRS, then it is a European Pharmacopoeia standard and should be ordered from the European Pharmacopoeia (website; email

There are very few other standards that are referenced in BP monographs that may be obtained from other sources. Please refer to Appendix I E of the BP for further information.

Only those standards which are followed by the letters BPCRS are available from the BP Laboratory.

Q.  What is the "current lot" system?

A.  In order to minimise the number of changes in batch number, the "Current Lot" system is used. When a substance is released for use as a BPCRS this substance is retested regularly to confirm it's continued suitability for use. No expiry date is given and the substance is replaced only when exhausted (or in rare cases when it is no longer suitable for use). This system reduces the number batches replaced due to expiry and helps to reduce the costs of producing BPCRS.

Q.  What is the expiry date of my BPCRS?

A.  BPCRS are supplied with a shelf life of three months from the date of despatch. The current lot is always valid for use when supplied and Customers are advised to order only as required. The assignment of the three months expiry period after despatch is to allow customers some time to use vials after purchase, particularly when a lot has been replaced and is no longer the "valid lot". Once the vial leaves our storage facility we no longer have control and therefore cannot guarantee the material. After this point it is up to the purchaser to make a decision whether or not to use the vial based on sound reasoning and their own knowledge of how the material has been stored.

BPCRS are monitored for stability and the valid lot is shown on our website. Your vial will remain current for use, as long as the lot is shown on the website and it is stored in its original unopened container at the appropriate conditions. As you state that you have stored it appropriately then it still valid.

Since we have no way of verifying how customers have stored the vials, we can only give a limited "guarantee" of the BPCRS for a short time. After this, it must be the responsibility of the user to ensure correct storage and use.

Q.  How should I store my BPCRS before use?

A.  BPCRS should be kept under the conditions stated in the appropriate monograph of the BP or BP (Vet). All BPCRS should be stored in well-closed containers and it is recommended that they are stored below 25°C. A BPCRS used for assay purposes should be stored between 2°C and 8°C.

We advise that BPCRS should not be kept for longer than 3 months from the date of despatch, as after this time the quality of the BPCRS is not guaranteed.

Q.  Can I store my BPCRS after opening and use it again at a later date?

A.  This is not advised. BPCRS are supplied in single use packs containing sufficient quantities to perform the tests prescribed in the monograph.
If the BPCRS is used for quantitative analysis, then it should be discarded after use. If the BPCRS is not for quantitative use (for example a resolution test mixture) then it may be possible to store the BPCRS as a solid or in solution and use again at a later date. In this situation, the analyst should satisfy himself or herself that the BPCRS is still suitable for use after storage.

Q.  How can I find out the declared content of my BPCRS?

Q.  What is the potency of my BPCRS?

Q.  What is the purity of my BPCRS?

A.  Not all BPCRS are supplied with a declared content figure.  This is dependent on the use of the substance and you will receive a leaflet with the BPCRS stating the current lot and the declared content ("purity") figure, if one is given.  The current lot and declared content are also stated in the website catalogue.

Q.  What information will I receive with my BPCRS?

A.  Leaflets, which accompany the BPCRS, contain important information regarding analytical data, storage conditions and advice on safe handling where necessary. Certificates of analysis (C of A's) are not supplied. Declared content figures are supplied where required.

Q.  Will I receive a certificate of analysis?

A.  No. All BPCRS are supplied with sufficient information to perform the intended test(s). Certificates of analysis are not supplied. Declared content figures are supplied where required.

Q.  What is the customs tariff code for BPCRS?

A.  All BPCRS are covered by the customs tariff code 3822.00.00.00 "Reference Material for Laboratory Use".

Q.  Can I use the BPCRS for a method that is not the same as the monograph method?

A.  BPCRS are intended only for use in the tests and assays of the BP or BP (Vet) in which they are required and may not be suitable for any other use. The declared content figures are calculated using the prescribed methods. If the BPCRS is to be used for a method other that the one prescribed in the BP, then it is the responsibility of the analyst to ensure that the BPCRS is suitable for this other use.

Q.  If no declared content figure is provided, can I assume that the content is 100%?

A.  No.  Declared content figures are only given if the standard is used for assay purposes in the monograph. Where no declared content figure is provided, this does not mean that the substance is 100% pure.  If you want to use a BPCRS without a content figure for quantitative analysis other than as prescribed in the monograph, then you need to determine an "in-house" content figure for your own particular use and assure yourself that this figure is robust.  The BP Commission cannot be held responsible for the accuracy of such figures.

Q.  If we are testing to a BP monograph for a pharmaceutical dosage form, can we use a different reference standard and treat as equivalent to the BPCRS?

A.  To evaluate any product against a BP monograph, the reference standard specified in the monograph should be used. If the monograph specifies BPCRS, the BPCRS should be used. If the monograph specifies EPCRS, the EPCRS should be used.

It is only acceptable to use a different reference material from the one specified in the monograph if the alternative has been validated against the prescribed standard. Substituting without supporting data is not acceptable.

Q.  How are BPCRS standards qualified?

A.   All BPCRS are thoroughly tested prior to release to establish their suitability for use. The amount of testing applied is dependant on the intended use and is controlled by our internal procedures. We assign declared content values using the determined values of water, impurities, solvents etc. We also determine assay using absolute method(s) and compare our results with at least one other Laboratory.

The identity of all BPCRS is confirmed by absolute methods again the details are covered by our internal SOP.

For BPCRS that are mixtures, the homogeneity of the mixture is established.

All new and replacement batches are approved for release by the BP Commission. 

Q.  What is the impact of the European REACH directive on supply of BPCRS reference standards?

The European directive EC 1907/2007 on the Registration, Evaluation, Authorisation and Restriction of chemical substances (REACH) is now in force. Following a review of the European Chemicals Agency (ECHA) website and consultation with the European Commission Institute for Reference Materials and Measurements (IRMM) it appears that the impact for BPCRS reference materials is as follows:


Since the quantities of BPCRS produced are very small, a maximum of 250 g per substance in any one year, no registration is necessary.


Work is currently ongoing to continue updating all Material Safety Data Sheets in line with the directive and these will be made available on the website as they are completed.


No BPCRS are currently on the list of Substances of Very High Concern (SVHC).