Bioequivalence and Bioavailability Forum • LLOQ “low enough”?

LLOQ “low enough”? [Bioanalytics]

posted by Ohlbe – France, 2013-01-11 20:16 (4919 d 01:55 ago) – Posting: # 9830
Views: 8,901

Dear John,

❝ I think with a 0.25-0.5ng/mL as LLoQ maybe doable.

❝

❝ If 40% of the subjects still show many BLQs with some detectable values not much higher than the LLoQ while the other 1/2 show normal concentration ranges then I don't see how I can justify that the parent compound measurement is deemed reliable for bioequivalence assessment.

In December 2009, CT Viswanathan participated in a meeting of the French Society for Quality Assurance (SoFAQ) in Paris. Somebody asked a question like "but if it is difficult to...". Vish's answer was:

what do you call difficult ? You'll have to show how hard you tried, not just say you did not succeed
if the lab you're using does not have the equipment needed to do the job: go to a better equipped lab
nobody said you had an easy life and an easy job...

Vish has left the FDA, but the spirit is probably still there. I don't know what molecule you're dealing with, maybe it is particularly difficult to ionise in MS/MS. Otherwise there are chances that going down to 0.25 ng/ml or lower will not sound such a challenge to the average FDA reviewer, with the latest LC-MS/MS systems and a proper sample preparation.

Regards
Ohlbe

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Regards
Ohlbe

Complete thread:

FDA definition of non-accurately and reliably jag009 2013-01-09 22:20
- Experiences with EU submissions Helmut 2013-01-10 14:03
  - Experiences with EU submissions jag009 2013-01-10 16:36
    - Experiences with EU submissions Helmut 2013-01-10 16:56
      - Experiences with EU submissions jag009 2013-01-10 20:07
        
        LLOQ “low enough”? Helmut 2013-01-10 20:46
        
        LLOQ “low enough”? jag009 2013-01-11 15:20
        
        LLOQ “low enough”?Ohlbe 2013-01-11 19:16
        
        LLOQ “low enough”? jag009 2013-01-11 20:14