Imp quantification

[Serpico]

Hi all,

Quick question if I may:

What are your views and those of the FDA etc on quantification of imps by RRF?

Specifically - would you quantify imps based on external standard (of the main compound) with an RRF. Or would you just quantify off the main peak in your actual sample and again apply the appropriate RRF?

I would assume the former is the 'most' GMP but is the later just as valid?

Ultimately...for GMP analysis do you run standards or just SST, Blank, LOQ and samples?

Many thanks,

Serp

[Rob Burgess]

We just quantitate against the main peak by % a/a and apply RRF of impurity peaks if we happen to have them.

As far as I am aware this is pretty much standard practice in pharma.

Using this approach you would only need to run external standards if you were also looking to aqcquire assay content data. Prefrably I run a separate fast LC method to acquire content assay data.