Definition
Requirements
Guidelines
Pharmacopiea
Types of Reference Standards
SOP for handling of Reference Standards
Qualification of Secondary Standards
Assigning Potency, Storage and Use
Documents & Records
2. Content
Definition
Requirements
◦ Guidelines
◦ Pharmacopiea
Types of Reference Standards
SOP for handling of Reference Standards
Qualification of Secondary Standards
Assigning Potency, Storage and Use
Documents & Records
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3. Definition (ISO-Guides 30-35)
Reference Material (RM):
Material, sufficiently homogeneous and stable with respect to
one or more specified properties, which has been established
to be fit for its intended use in a measurement process
Certified Reference Material (CRM):
Reference material characterised by a metrologically valid
procedure for one or more specified properties, accompanied
by a certificate that provides the value of the specified property,
its associated uncertainty, and a statement of metrological
traceability.
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4. Definition (ISO- Guides 30-35)
Primary Standard:
Standard that is designated or widely acknowledged
as having the highest metrological qualities and
whose value is accepted without reference to other
standards of the same quantity, within a specified
context.
Secondary Standard:
Standard whose value is assigned by comparison
with a primary standard of the same quantity.
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5. Definition (ICH Q7)
Reference Standard, Primary:
A substance that has been shown by an extensive set of
analytical tests to be authentic material that should be of high
purity. This standard can be:
◦ obtained from an officially recognised source, or
◦ prepared by independent synthesis, or
◦ obtained from existing production material of high purity, or
◦ prepared by further purification of existing production material.
Reference Standard, Secondary:
A substance of established quality and purity, as shown by
comparison to a primary reference standard, used as a
reference standard for routine laboratory analysis.
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6. ICH Q7: PRS Requirement
11.17. Primary reference standards (PRS) should be
obtained as appropriate for the manufacture of APIs.
The source of each primary reference standard should be
documented and Records should be maintained.
Storage and use as per supplier’s recommendations. Storage and use as per supplier’s recommendations.
PRS obtained from an officially recognised source are used
without testing if stored as per recommended conditions .
11.18 Where a PRS is not available from an officially
recognized source, an “in-house primary standard” should be
established.
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7. ICH Q7:PRS Requirement
Appropriate testing should be performed to establish fully the
identity and purity. Documentation of this testing should be
maintained.
11.19. Secondary reference standards should be appropriately
prepared, identified, tested, approved, and stored.
The suitability of secondary reference standard should be
determined prior to first use by comparing against a primary
reference standard.
Each batch of secondary reference standard should be
periodically re-qualified in accordance with a written protocol.
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8. EU GMP: Requirement
EUGMP EudraLex Volume-2, Part-1 Chapter-6 QC- 6.20
Reference standards should be established as suitable for their
intended use. Their qualification and certification as such should
be clearly stated and documented.
Whenever compendial reference standards from an
official source exist, these should preferably be used as
primary reference standards unless fully justified (the use of
secondary standards is permitted once their traceability to
primary standards has been demonstrated and is
documented.
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9. European Pharmacopoeia
5.12. REFERENCE STANDARDS (General Chapter):
A Primary standard is characterised by a variety of analytical
techniques chosen to demonstrate its suitability for use .
A Reference standard corresponding to an impurity is
characterised for identity and purity with minimum content ofcharacterised for identity and purity with minimum content of
95.0 %, The content being considered as 100.0% since there
will be no appreciable effect on the determination of impurities.
EP Reference standards are mostly stored in temperature at 5 ±
3 °C, otherwise specified in leaflet.
If the standard is presented in multi-use containers then re-
testing may be more frequent for hygroscopic or oxygen-
sensitive substances. Eg water/LOD content
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10. European Pharmacopoeia
Secondary standard. A standard whose property value is
assigned by comparison with a primary standard of the same
property or quantity.
A secondary standard should exhibit the same properties as
the primary standard, relevant test(s) shall be performed. The
extent of testing may be scientifically justified. Quantitative
purpose required comprehensive test to establish potency.
The secondary standard is established by comparison with the
primary standard to which it is traceable.
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11. Type of EP CRS
Type of Reference Standards available in EDQM
◦ Identification
◦ Assay
◦ Impurities Quantitative
◦ Impurities Qualitative
◦ Mixtures for System Suitability/ Peak Identification.
Purpose/Usage:
◦ Batch testing & release
◦ System suitability test
◦ Evaluation of a measurement system
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12. Type of EP CRS
Availability of EP CRS other than API & Impurities
• Reference spectrum
• Elemental impurity: eg,Lead solution CRS (1.00 mg/g)
Instrument calibration / qualification
Caffeine CRS for – Calibration standard for MR, WL accuracy for LC
◦ Sodium Aminosalicylate dihydrate CRS for equipment qualification /
Calibration. – Loss on drying(2.2.32 ) Value: 169.6 (± 2.4) mg/g;
Uncertainty: 0.4 mg/g
Refer Leaflet Contains: Scientific information, purpose, use, potency,
uncertainty of assigned value, Instruction for use, validity, Storage
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13. USP RS: General Chapter <11>
Official applications of USP RS are specified in the
monographs and general chapters.
Pharmacopeial Reference Standards are highly
characterized specimens
Where USP states in the monograph that use USPRS, in Where USP states in the monograph that use USPRS, in
the Assays and/or the Identification tests.; It is legal
requirement.
Secondary standard can be used, but it should be qualified
using the USPRS.
Potency or content of USP RS is assumed as100.0% pure,
unless otherwise directed or stated in the label
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14. USP RS: General Chapter <11>
In case of dispute in the test results, value obtained using the
specified USP RS is conclusive.
If any USP RS is not yet available, that portion of the standard
containing the requirement shall not be official until USP RS is
availableavailable
USP Reference Standards for Assay and Identification for
Qualitative or Quantitative purpose.
Refer for more details:
◦ Technical Data Sheets or Typical Chromatograms.
◦ Weights and Balances 〈41〉 & Volumetric Apparatus 〈31〉
◦ 6.50.20.1 Adjustments to Solutions in the General Notices
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15. Types of Reference Standards
USP Reference Standards for Impurities;
Organic impurities: Starting materials, intermediates, by-products,
reagents, catalysts, and/or degradation products.
Inorganic impurities: Reagents, catalysts, heavy metals, or
inorganic saltsinorganic salts
Residual solvents that may be either inorganic or organic liquids.
Authentic Visual References (AVR) are used for visual images
to compare certain test that they meet compendial requirements.
Performance Verification Test Standards- Instruments
qualification and calibration. Method-specific uses, (e.g.,
performance verification standards, AVR, melting point standards,
and the particle count set)
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16. Information: USP RS
USP RS are provided with Technical Data Sheets or
Typical Chromatograms.
USP RS do not carry an expiration date on the label. It
may be used as long as it is listed as "Current Lot" in the
Catalog or has not reached its Valid Use Date.
Catalogs published USP website (check quarterly for
validity)
Upon depletion, the lot is designated in the catalog as
"Previous Lot" and a "Valid Use Date" is assigned.
Refer for more details@ https://www.usp.org/reference-standards
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17. How to Use USP RS
Use USPRS as per Technical data sheet or as per label
As Is: Use without any prior treatment or correction for volatiles.
(confirm from valid data that the volatiles are constant over time)
Dry Before Use: Use immediately after drying under stated conditions.
Drying should not be performed in the original container. A portion of
the material should be transferred to a separate drying vessel.the material should be transferred to a separate drying vessel.
Determine Water Content Titrimetrically At Time of Use: Use with a
correction for the water content or the loss on drying, determined on a
separate portion of material.
◦ Test Water Determination as per Method I (921).
◦ Instrumental or microanalytical methods are acceptable
◦ When about 50 mg of RS is used for water test, use dilute reagent with 2 to 5 fold
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18. How to Use USP RS
Some of the USP RS provided in single-use containers.
Labeled as reconstituted in its entirety without any
additional weighing, where given in the monographs.
Intended use and that value assignment and uncertainty
information are considered.
USP RS should be stored in the packaging configuration
provided by USP (e.g., vials packaged in hermetically
sealed).
When special storage conditions are specified, label
directions should be followed.
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19. SOP for Handling of RS/CRS
Establish the procedure for handling of Reference standards
to address the following, but not limited to ;.
Purpose & Scope
Responsibility: Assign co-ordinator for handling
reference standards/ working standards
obtained from an officially recognized source like
Pharmacopoeia reference substances / certified RS
Ordering and receipt of RS/CRS
Label with details
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20. SOP for Handling of RS/CRS
Maintain the records such as PO, date of receipt, COA or
leaf let,
Storage: store as per storage condition in secured area
Use appropriate RS for testing, calibration, qualification of
equipment, instruments or other devices
Usage log with purpose and reconciliation
Periodic verification of validity or availability of new
standard
Include the qualification of secondary reference standard
or Prepare separate SOP.
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21. Qualification of Secondary Standard
Qualification of Secondary /Working standard:
Standard for Quantitative Use :
Extensive physico-chemical testing is required for the standards
used for quantitative purpose.
The level of characterization depends on the intended use The level of characterization depends on the intended use
Choose the tests & method to confirm the mass balance.
The secondary /working standard can be procured external
source or synthesis or select from commercial batch.
Assay: Select one of the batches which have minimum 99.0% of
assay /purity and confirm the homogeneity
Purify the material further if purity is less.
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22. Qualification of Secondary Standard
Qualify against official Reference Standard (USPRS / EPCRS)
Test the assay / chromatographic purity at least in triplicate
Test other parameters, which are related to potency like Loss
on drying and / or water by TGA or Karl Fischer, Residual
solvents, Residue on Ignition etc.
Perform Inter-laboratory study to assign a content (if required) Perform Inter-laboratory study to assign a content (if required)
Calculate the uncertainty of measurement
Recommended to assign the content on an “as is” basis.
Assign the potency / content based on mass balance
considering LOD / water content, Residual solvent or ash
content etc
Potency = (100 – LOD/water/solvents/inorganics) x chromatographic
purity(%)/100.
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23. Qualification of Secondary Standard
Assigned value has to be checked by Orthogonal techniques
like non-aqueous titration or other suitable techniques, such as
CHN-analysis.
Perform characterization against official reference standard –
Mass, FTIR, NMR, UV spectroscopy DSC, XRD polymorph asMass, FTIR, NMR, UV spectroscopy DSC, XRD polymorph as
required.
In case of impurity standard; select the assay/purity of min 95%
Record all the details like source batch, tests, primary reference
used, and potency and keep the COA
Maintain the test record with raw data, ref standard used.
Pack and Label the vials with potency, use, validity and storage .
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24. Qualification of Secondary Standard
Standard for Quantitative Use : (RT Identification or system suitability)
Procure or synthesis or select from in-house, ensure that content is at
least 95% If t is less justify scientifically for its suitability.
Test against reference standard (if available); otherwise perform
complete test for characterization.
Test the following physico-chemical properties to elucidate the structure.
Chromatographic purity, FTIR- UV spectrum, mass, NMR and CHN-
analysis and prepare the COA with traceability
Maintain the test record with raw data, spectrum, chromatograms.
Pack and Label the vials with potency, validity, storage and pre-defined
date for use and numbering the vials
Retest and confirm to extend the validity / usage period.
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25. Instruction for Usage
Take a reference standard vial from storage area and allow to
controlled room temperature prior to weighing
Open the reference standard vial carefully and keep the inner cap and
outer cap in the inverted position on a clean butter paper.
Use a clean stainless steel spatula or paper for one time use for Use a clean stainless steel spatula or paper for one time use for
transfer of RS.
Don’t return unused standard to the vial.
After the weighing / transfer close the vial immediately
Don’t expose the reference standard for too long to avoid pick up of
moisture.
Return the closed vial to their respective places, securely.
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26. Label: Reference Standards
Reference standards labelled with information
including
◦ In-house ref. No
◦ Name
◦ Batch, lot NoBatch, lot No
◦ Date of opening
◦ Shelf-life (if applicable)
◦ Potency
◦ Storage conditions
◦ Usage condition
◦ Vial No.
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27. Records for Reference standards
Record for reference standard
Ref No /identification No. of the material
Description of the material
Source & date of receipt
batch designation or other identification code
Potency , LOD any other details as appropriate
Intended use of the material (e.g. as an infrared
reference material, as an impurity reference material
for thin-layer chromatography, etc.)
Location of storage in the laboratory, and any special
storage conditions
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28. Packing and Use:
Pack the working standard in 2ml/5ml/10ml vials or as appropriate.
Pack required number of vials based on the requirement and frequency
of use, eg. one vial for each month / three months
Assign the validity / expiry based on the shelf-life
Pack required number of vials and assign validity of each vial. Record
the details in the working standard usage login register
If molecule is stable assign 2 years and the extent validity period after
retest. Specify clearly in the SOP extend the validity period for 6
months.
Label the vials and store at recommended storage condition.
Record the opening date use until the valid date of vial
Dispose the excess sample as per validity/ expiry date.
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