Presumably, each analytical method begins with a measured mass of drug product being extracted for analysis. Impurities results are then mass impurity per mass drug product. Similarly, content assay results would be mass API per mass drug product. The two results can be compared because they are both relative to drug product unit mass, i.e., for each unit mass of drug product, there is x mass of API plus x mass of impurity A, B, C, etc. If the unaccounted amount is significant, i's possible that not all degradation products are being quantified or that the degradation products do not respond with the same detection intensity, e.g., UV spectral maximum or MS selective ion. I hope this helps.
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Marla Emery
Saint Paul MN
United States
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Original Message:
Sent: 23-Apr-2022 07:10
From: Urvish Kumar Shah
Subject: Analytical Method
Hi All,
In the development of one of the generic drug product, Assay method is by HPLC and Organic Impurities is by GC-MS. Is it possible to calculate, Mass Balance in the forced degradation of Organic Impurities method? If possible, can any one suggest the method?
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Urvish Shah
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