Bioequivalence and Bioavailability Forum

Dear all,

I have a big problem :(:(:(

I'm developing olanzapine method by UPLC-MS/MS with olanzapine-d3 as internal standard. I have a few runs with very good results but a lot of runs with bad results just for QC1 levels, because of big interferences.

Although interference areas are too high, they do not effect QC2 levels and 9 out of 10 different blank sources have no interference. Matrix effect analyses were performed twice with different concentrations and %CV values are 15 and 16.

In one of matrix effect analysis one set of blank sample has both olanzapine and olanzapine-d3 peaks each of 6 injections with different amounts (we expect to observe only olanzapine-d3, because internal standard stock solution was spiked in to tubes).

Also, same results were observed with different analysts and different days.

What do you suggest to us?

Thank you all,
Hale