USP37 Mannitol monograph, related substance verification, LC

[sisay]

Hi all

USP monograph link: http://www.usp.org/sites/default/files/ ... nnitol.pdf

Currently i found that the content of related substance of Mannitol monograph has been revised per USP37 2nd supplement and I have few questions as follows:

1. Detector temp: It is set to "40C (maintain at a constant temp)". In previous version, it only stated "maintain at a constant temp". In our previous verifcation, it was set to 50C. In this case, should I re-verify our method as I can not find any modification range of RI detector temp regarding USP37 <621>?

2. As this related substance is limit test, which solution listed in the monograph (System A, System B, STD A, STD B and STD C) should be the standard solution to check HPLC system suitability (%RSD, n=6)?

In my opinion, System A and System B is to check resolution and identification, STD A is for Assay purpose, STD B (maximum limit) is compared by Sample, and STD C is as sensitivity solution. So in this case, STD B should be the STD solution to check HPLC system suitability.

Hope you can provide me any valuable information, reference or weblink. thank you in advance.!

sisay

[Consumer Products Guy]

USP <621> allows for column temperature to be +/- 10C of stated monograph temperature to be without any validation required. I would think that you could make a decent case that such temperature variation would have greater affect on the assay (= none) than the same 10 C change in detector temperature.

A QC expert might say to inject the same vials using both temperatures, and document that the results are indistinguishable or equivalent (try defining those terms), and then just make the change to 50 C detector temperature.