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krishnamurthy ca ☆ 2008-01-18 07:03 (6733 d 23:29 ago) Posting: # 1523 Views: 4,677 |
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Dear Members This is with regard to use of internal standards in LCMSMS bioanalytical techniques. During method validation and subject 1 to 4 plasma sample analysis, Metoprolol succinate was used as IS. Since it got exhaused, we used Metoprolol tartrate as IS from subject 5 to 12, with necessary corrections for molecular weight. is this an acceptable practice ? -- Edit: Category changed. [HS] |
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vpardhasaradhi ☆ 2008-01-25 05:47 (6727 d 00:45 ago) @ krishnamurthy ca Posting: # 1555 Views: 3,632 |
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Dear Mr. Krishnamurthy, It is definitely not acceptable. You should have at least carried out partial validation proving that your new internal standard does not cause interference and also ion suppression/ ion enhancement to your analytes. In addition you may need to conduct few precision and accuracy batches, recovery and post preparative stability tests. Since, you have already proceeded further without these, it is better you complete these procedures at least now and file them with your study documents. With best regards, V.Pardhasaradhi |
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Roshini ☆ 2008-01-25 06:08 (6727 d 00:24 ago) (edited on 2008-01-25 11:19) @ vpardhasaradhi Posting: # 1557 Views: 3,585 |
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Hi Krishnamurthy, Since it is quantification of metaprolol it should be OK provided we apply molecular weight correction. Succinate or tartarate should not make a difference since in the MV parameters mentioned we do not quantify the salt but only the free compound. With best regards, Roshini Singh -- Edit: Full quote removed. Please see this post! [Ohlbe] |
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