Assay (anhydrous substance) HPLC calculation- Ph.Eur. interp

[juju]

Hello,
In some Ph.Eur monographs there is a request for the HPLC assay for example: Content: X% toX% (anhydrous substace).
I am interested if somebody takes into account for calculation of the assay content of the substance [b]both the water and the residual solvents? [/b]

In EDQM FAQ -Helpdesk List there is the question and the answer about this:
21. The definition of substance X gives the content on dried or anhydrous basis. What about the solvents, are they to be taken into account when determining the assay?
In accordance with the general monograph Substances for pharmaceutical use (2034), the content of residual solvents is taken into account for calculation of the assay content of the substance, the specific optical rotation and the specific absorbance. This information is therefore not indicated in the specific monographs concerned.

Thank you and Best regards
Ana

[juju]

Hello,
nobody is answering. Please...

ana

[aceto_81]

I think you answered your question by yourself, if you read carefully:

"In accordance with the general monograph Substances for pharmaceutical use (2034), the content of residual solvents is taken into account for calculation of the assay content of the substance"

So the residual solvents are taken into account.
And when you say anhydrous substance, I'm pretty sure the water content is taken into account.

Therefore: Yes, both the water and residual solvents are taken into account for the calculation.

Ace

[juju]

Thank's a lot. I know that, but I asked becouse some people don't want to understand like this.

ana

[chetan_mehwala]

But when loss on drying is given that time only LOD should be consider
not LOD + Residual solvnet
am i right?
Regards,
CKM

[juju]

Yes
Ana