Bioequivalence and Bioavailability Forum • Internal Standard Variation

Internal Standard Variation [Bioanalytics]

posted by Ohlbe – France, 2007-09-09 00:32 (6855 d 23:27 ago) – Posting: # 1062
Views: 17,631

Dear Harish,

I agree with HS, the main question will be: is the peak area ratio affected by the IS variation or not ?

Supposing the ratio is not affected, another issue is the case of samples with a very low concentration, close to the LLOQ. If your signal (both for your analyte and your IS) is only e.g. 1/4 of what it should be, you may end up with an analyte peak that cannot be measured correctly (too small, or signal to noise ratio too high). You would then incorrectly report it as < LLOQ.

You can define criteria for repeat analysis due to IS variation either in a general SOP or in the method SOP itself (based on what you observed during method validation).

Regards
Ohlbe

Complete thread:

Internal Standard Variation Dr. Harish L. Rao 2007-09-08 14:16 [Bioanalytics]
- Internal Standard Variation Helmut 2007-09-08 16:43
  - Internal Standard VariationOhlbe 2007-09-08 22:32
    - Internal Standard Variation Helmut 2007-09-09 00:37
      - Internal Standard Variation Charl 2007-09-09 12:25
        
        Internal Standard Variation Jaime_R 2007-09-09 13:13
        
        IS vs ES methods Helmut 2007-09-09 15:05
        Internal Standard Variation Charl 2007-09-10 10:10
        
        Internal Standard Variation Jaime_R 2007-09-10 18:58
      - Internal Standard Variation Ohlbe 2007-09-09 23:20
        
        Internal Standard Variation Helmut 2007-09-10 20:33
- Internal Standard Variation vamshi 2008-08-14 12:33
  - Internal Standard Variation ElMaestro 2008-08-14 14:09
    - Internal Standard Variation Helmut 2008-08-14 20:28
      - Internal Standard Variation ElMaestro 2008-08-15 16:51
        
        Internal Standard Variation Helmut 2008-08-15 17:29