SOP of Reference Standard Management

The purpose of this SOP is to lay down a procedure for entry and exit in laboratory in Quality control department.


  Reference standards :

Receive the Reference substances check current lot, material safety data sheet and certificate (If available). Allot a reference number to it as illustrated below. USPRS/A1/1.

In this, ‘USPRS’ stands for the pharmacopoeial body from which the RS is received. ‘A1’ stands for the unique number for a particular product in the alphabetical series and ‘1’ stands for the version number.

Make sign and date on original container of reference substance/ standard.
Maintain a reference substance register (Annexure I) and enter the details like item, RS number, Lot/Batch number, date of receipt, quantity received, direction for storage and use.

Maintain an index of all reference substances/standards and attach it to the register.  
      Place the reference substance container in a self-sealing polythene bag, along with a silica gel pouch, which is kept in a small stainless steel container with the label (Annexure II) indicating item, RS number, lot/batch number, date of receipt and direction for storage and usage.

Replace the silica gel pouch of the container every six months and record the same.  Refer Annexure III.

Prepare a usage log for each reference substance indicating its usage and maintain a record  of the same.

Check the validity of lot No./Batch No. of reference substances/ standard from official catalogue of pharmacopoeial bodies every two months or whenever a new catalogue is received whichever is earlier.
  Reference substance should be up to the lot/Batch No. is valid Whenever a new lot is received or a new container of same lot is received, replace old lots/batches of reference substances with the new lots.

Retain the same reference number  but revise a version number e.g. USPRS/A1/2 and so on.

Assume the potency to be 100% if the same is not specified on the original reference substance container or catalogue of respective pharmacopoeial bodies.

Where drying of reference substance is specified, dry only the minimum required quantity of the reference substance.

Do not dry the original container under any circumstances.

Do not transfer the dried/ weighed substance back to the container.

In case the instructions for use mention determination of moisture content by Karl Fischer apparatus, use the bare minimum quantity by diluting the Karl Fischer reagent three to four times with methanol or using diluted Karl Fischer reagent (water equivalence factor 1 to 2 mg/ml) or determine moisture content using coulometer.

After withdrawing reference substance vial from refrigerator, allow it to attain ambient temperature before proceeding with testing.

Make relevant entries in the usage log every   time the reference standard is used.

Unless otherwise mentioned, store all the reference substances at temperature between 2 to 8°C.

Allow it to attain ambient temperature before use. Destroy the old reference standard and mention the details of destruction in usage log.  

Reference substance solutions :   Prepare the RS solution only whenever it is required.

Allot a reference number to it as illustrated below:  RSSoln/A1/1.

In this, ‘RSSoln’ stands for Reference Substance Solution,  ‘A1’ stands for the unique number for a particular solution in the alphabetical series and ‘1’ stands for the version number of reference solution.

Store reference substance solutions in tightly closed bottles with proper labeling) and protect them from light Maintain a register and enter the details like item, solution number, source number of material used, test name, validity (6 months) .
Maintain an index and attach it to the register. Prepare a “Solution Preparation and Usage Log” indicating name of solution, date of preparation, RS No. For which RS solution prepared, dilution, direction for use.

Unless otherwise mentioned, store all the reference solutions at a temperature between 2 to 8°C.

Allow it to attain ambient temperature before use.

Check the solution for colour, clarity and foreign particles, before use. 

Carry out the periodic checks for colour, clarity and foreign particles once in every 3 months and record the observations.

If change is observed, discard the RS solution.

Prepare fresh solution, Retain the same solution number but revise version number. e.g. Solution/A1/2 and so on.

If the Lot No. / B.No. of the reference substance (used for the preparation of reference solution) is changed, discard the reference solution and replace with fresh solution.

After initial analysis, maintain the records of data related to the solution used e.g. copy of HPLC/GC chromatograms or in case of TLC, observation of TLC pattern (i.e. number of spots observed) and attach with the usage log..

After every analysis, compare the data obtained related to RS solutions used with the data of initial analysis.

If any significant change is observed (like major degradation peaks observed in case of chromatographic tests) discard the solution and prepare the fresh solution.

Record the observations and comparison in preparation and usage log.

As per SOP of Employee Training


As per SOP on SOP


Annexure I     :  Reference standard vial Register

Annexure II   :  Label of Reference standard Container / bag

Annexure III :  Reference standard consumption Record

Annexure IV :  List of Reference standard.

Annexure V :  Silica gel Change record

Annexure VI :  Reference solution Label

Annexure VII:  Reference solution index

Annexure VIII : Reference solution Preparation and usage log



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