amlodipine and valsartan tablets dissolution USP method

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Hi there. I´m having trouble with this analysis, amlodipine besylate.
I cannot get concordance within standards and the biggest problem, areas whitin days vary. I´ve tried all hplc we have (Promeinence, 1260 and 1100) and always same problem. One day in an hplc you get some area, and the other day, same hplc, same mobile phase (or new), and response changes. Tried another standard from different source but nothing different happened, same problem. Instruments are qualified, is the only product I´m seeing this. But not with Valsartan, only amlodipine, and the system is the same because it´s a gradient, you quantify both peaks.
Anyone has experience with this monography?
Q. F. Ignacio Viera
Hello. May amlodipine be just unstable?
Best regards,
Dmitriy A. Perlow
You need to work systematically here!

1. Areas change: How? larger/smaller? Progressively or randomly?

2. Do you work wth the sandard or the samples?

3. Do you use the same solutions each day or do you dissolve new samples/standards every day and se these area variations.

Best Regards
Learn Innovate and Share

Dancho Dikov
3 posts Page 1 of 1

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