To lay down a standard procedure for preparation, maintenance and storage of the working standards used for analysis of Raw material, semi finished products and finished products.

2.0    SCOPE:

This SOP is applicable to preparation, maintenance and storage of working standards in Quality Control department at ( Company Name)


Officers / Executive – Quality Control shall be responsible for complies of this SOP


Manager- Quality Control and Head QA shall be accountable for compliance of this SOP.

5.0    Attachments:

           Working standard vial label                                               Attachment-I

Test data for working standard qualification                            Attachment-II

Certificate of analysis for working standard                              Attachment-III

Working standard preparation, issuance                                   Attachment-IV

and destruction record

List of working standard                                                               Attachment-V

Consumption record of working standard                                 Attachment-VI


  • Development, Qualification and storage of working standards:

6.1.1  Working standards shall be prepared and standardized with the Reference standards (USPRS/CDRL RS/ BPCRS/ IPRS certified RS) for the routine use. In case if reference standard of the material is not available, procure the working standard from the approved manufacturer.

6.1.2 For development of WS, select one approved raw material, tested as per respective pharmacopoeia or in-house specifications.

6.1.3 Selected raw material shall have maximum purity and minimum impurity level and whose expiry period shall be beyond 12 months.

6.1.4 Requisition shall be given to stores for the selected raw material. Sample to be drawn by QC chemist as per the sampling procedure.

6.1.5 If the approved raw material is being used for preparation of working standard within 6 months of its approval, then related substances/ impurity shall be referred from approved raw material test report.

6.1.6 Perform following tests for assigning potency to the working standard:-



Water Content / Loss on drying.

Related Substances


6.1.7 Above tests should be carried out as per the standard testing procedure mentioned in respective specification by three Analysts.

6.1.8 Record the analysis in the working standard Qualification Test data sheet as per attachment-II

6.1.9 Inject five replicate injections of reference standard solution for system suitability.

6.1.10The Relative Standard Deviation of area of replicate injections for system suitability should comply as per the respective standard testing procedure.

6.1.11For material specified in pharmacopoeia system suitability should be performed, as per respective pharmacopoeia.

6.1.12Calculate the assay values with respect to average area of reference standard solution. The RSD of   these assay values should not be more than 0.5%. Take the average of assay values as working standard   potency.

6.1.13If RSD is more than 0.5%, perform the standardization by using freshly   prepared reference standard and working standard solutions.

6.1.14Allot the working standard number as WS/YY/ZZZ; Where WS stands for working standard YY for  year and ZZZ serial number assign for working standard.

6.1.15Prepare certificate of analysis for the test performed for the qualification of WS. The format of COA should be as per the attachment – III

6.1.16Record all the details in the “Working Standard Preparation, Issuance and Destruction Record” refer attachment – IV.

6.1.17Use clean and previously dried vials to store the prepared working standard. These vials are closed with rubber bungs and sealed with aluminum seals. Prepare suitable No. of vials of each working standard and number the vials as 1/X to X/X (where X = No. of vials prepared).

6.1.18Prepare at least 13 vials for each working standard. Each vial shall be used within 1 month after opening and one vial shall be kept as reference.

6.1.19Revalidation of the working standards shall be done after six months from the date of preparation of the working standard as per the testing procedure of preparation of working standard .Label each vial as per attachment – I.

6.1.20Unless otherwise specified, all the vials of each working standard shall be kept in a appropriate container in the refrigerator at 2 – 80C properly labeled. Prepare a list of working standard refer attachment – I.

  • Issuance, usage and destruction of Working Standard:
    • Vial shall be issued by the HOD or authorized person to the analyst for its regular analysis and usage. Issuance activities shall be recorded in Format- attachment – IV.
    • After use of working standard, immediately Stopper and seal the vial properly and wrap with paraffin -film for hygroscopic material. Keep the vial back in the Desiccators (Filled with silica gel) kept in the refrigerator marked as “WORKING STANDARDS IN USE”.
    • Activate the silica gel at 105°C for 1 hour, twice a month or after its color change.
    • Shelf life of the working standard shall not be more than the shelf life of the raw material.
    • Remaining quantity (if any) of issued vial at the end of one month or after the end of shelf life shall be destroyed by dissolving in suitable solvent & there after discarding the solution.
    • Destroy all remaining amount of WS as per the procedure mentioned in at the end of the validity period and after development of the new WS.
  • Working/Reference Standards of Impurities:
    • In case of availability of AR grade material as impurity standard, it can be used as such.
    • AR grade material for impurity analysis shall be kept separately.
    • Impurities which are not available in reagent catalogue shall be procured from Pharmacopoeia agencies or vendors.
    • Stock solutions shall be prepared for the impurities obtained from the Pharmacopoeia agencies.
    • Stock solutions shall be stored in refrigerator in well labeled volumetric flask or other vial.
    • Stock solution shall be used till it meets the system suitability requirements.
    • If there is any secondary peak or change in response significantly, then fresh stock solution for impurities shall be prepared.



RSD: Relative Standard Deviation

HOD: Head of Department

USPRS: United States Pharmacopoeia Reference Standard

CDRLRS: Central Drug Research Laboratory Reference Standard

BPCRS: British Pharmacopoeia Chemical Reference Substance

LOD: Loss on Drying

WS: Working Standard

SOP: Standard Operating Procedure

QA: Quality Assurance

QC: Quality Control


        Quality Assurance Department

Quality Control Department

Version No. Date of Revision Reason for Revision
   Name of Raw material
Working Stanadard No.  
Batch No:
Preparation Date:
Valid up to:
Prepared By:      Checked By:

Attachment -II

Material Name  
Batch No.   Working Standard No.  
Mfg. Date   Exp. Date  
S T P  No.   A. R. Number  
Manufacturer   Reference  


  • Description: _______________________________________________________________________________________________
  • Identification:



  • % Moisture (If applicable):                                                                                             Balance  ID………………………

Instrument ID…………………..

Sr. No. Sample Weight % Moisture Analysed By Checked By



  • % Loss on Drying (If applicable):                                                                            Balance ID………………………

Oven ID…………………………..

Sr. No. Details Determinations
1. 2. 3.
A Wt. of empty LOD bottle (gms)
B Wt. of LOD bottle + Sample (gms)
C Wt. of sample (gms)
D Wt. of LOD bottle + Sample (after drying) (gms)
E % LOD = (B – D)/ C *100

Analysed By: 1st                              2nd                                3rd                                                       Checked By:

Sign/Date…                                                                                                                            Sign/Date…

  • Assay:
    • By UV/ HPLC / Titrimetric (Attach chromatograms / printout with this report)

           Calculation Formula:

 Analyst: 1st                                                                                                          Balance ID……………………..

                                                                                                               Instrument ID………………….





Analysed By:                                                                                                                                    Checked By:

Sign/Date:                                                                                                                                         Sign/Date:





Analyst: 2nd                                                                                                    Balance ID……………………..

                                                                                                                             Instrument ID………………….











Analysed By:                                                                                                                     Checked By:

Sign/Date…                                                                                                                       Sign/Date…


Analyst: 3rd                                                                                    Balance ID……………………

Instrument ID…………………











Analyzed By:                                                                                                                           Checked By:

Sign/Date…                                                                                                                             Sign/Date…


  • For microbiological assay (Reference report No.: __________________) Sign/Date:


% Assay 1. 2. 3.
% RSD  




Conclusion:          The above sample is Qualified / Not Qualified against _________ reference standard no. ___________ for use as a working standard.











  Analysed by:                                      Checked by. :                                                           Approved by. :

  Sign/Date:                                            Sign/Date:                                                              Sign/Date:




Attachment -III



Product Name: Report NO.:
Batch No : Qty Taken :     
Manufactured By : Supplied By :
Mfg. Date : Exp. Date :
Effective Date : Valid upto :
Reference : Working Standard No :


S. No. Tests Specifications Observations
1. Description
2. Solubility
3. pH
4. Related substances
5. Heavy metals
6. Sulphated Ash
7. Loss on Drying
8. Assay


Conclusion: On the basis of above test report as per I.P./ B.P./ U.S.P./I.H.S. the material  can be used as Working Standard.

Prepared by: Checked by: Approved by:
Date: Date: Date: