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?