Normal v/s reverse phase HPLC

[yogesh#14]

Hi All,

The API team at our site has developed a Normal phase method and the formulation -Analytical method is revese phase . The formulation cannot be analyzed on normal phase since it need to be diluted with water prior to analysis (since it is stock solution which needs to be reconstituted with water). Also in normal phase the detection wavelength is 315nm (the abs max for the compound is at 220nm and 315nm) since the mobile phase is mixture of chloroform and methanol. Incase of RP method the the detection is at 220nm.

Is it acceptable from regulatory point of view if the formulation is analyzed by reverse phase and the API method is normal phase?


I request you to kindly post your comments on the same.

Regards,

Yogesh

[Bernd]

Hello yogesh#14,

Your question is still not to understand: the type of analyze is depending on the compounds You have and the matrix or solvent. Let us know a little bit more.

Regards

Bernd

[Bruce Hamilton]

Provided you can convince the auditors that both methods work and have been fully validated for the samples being submitted and results being reported, there should not be any problems.

However, I'd be wanting management to sort out these issues as part of the product design process, and would have expected any equivalency issues to have been sorted out during method validation.

If perople are concerned, one of the groups could validate a method that also performs SPE or liquid-liquid extraction before analysis, so both are using the same type of chromatography - but why bother?.

Bruce Hamilton

[kladage]

Dear Yogesh,

In this case you need to demonstrate that the by both the methods the impurity profile is the same. You said that you cannot analyse the formulation by noram lphase. How about trying the API by reverse phase. If you are able to demonstarte that the API shows X impurities (no. and qty.) and the reverse phase also shows a similar profile, then you can very well retain noramly phase for API and reverse phase for formualtion.

Another point you need to keep in mind is queries will be minimised if you have the same method for API as well as formulation. Also for the formulator it is more ceonvenient if both the methods are same.

As far as wavelength is considered you need to decide this based upon the lambda max and response fac tors of known impurities at both the wavelengths.

[yogesh#14]

Hi All,

Thanks for the valuable comments. It has made the picture for me more clear. Thanks again...

Regards,

Yogesh