US 12,270,803 B2
Quantitation of tamoxifen and metabolites thereof by mass spectrometry
Nigel Clarke, Vista, CA (US)
Assigned to Quest Diagnostics Investments LLC, Secaucus, NJ (US)
Filed by Quest Diagnostics Investments LLC, Secaucus, NJ (US)
Filed on Oct. 25, 2023, as Appl. No. 18/494,030.
Application 18/494,030 is a continuation of application No. 17/893,950, filed on Aug. 23, 2022, granted, now 11,835,505.
Application 17/893,950 is a continuation of application No. 17/093,472, filed on Nov. 9, 2020, granted, now 11,428,682, issued on Aug. 30, 2022.
Application 17/093,472 is a continuation of application No. 15/830,812, filed on Dec. 4, 2017, granted, now 10,830,746, issued on Nov. 10, 2020.
Application 15/830,812 is a continuation of application No. 15/284,248, filed on Oct. 3, 2016, granted, now 9,835,606, issued on Dec. 5, 2017.
Application 15/284,248 is a continuation of application No. 14/710,311, filed on May 12, 2015, granted, now 9,459,267, issued on Oct. 4, 2016.
Claims priority of provisional application 61/992,214, filed on May 12, 2014.
Prior Publication US 2024/0060950 A1, Feb. 22, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G01N 33/94 (2006.01); G01N 30/72 (2006.01); G01N 33/15 (2006.01); G01N 33/48 (2006.01); G01N 33/49 (2006.01); H01J 49/00 (2006.01); H01J 49/10 (2006.01)
CPC G01N 33/15 (2013.01) [G01N 30/7233 (2013.01); G01N 33/49 (2013.01); G01N 33/94 (2013.01); H01J 49/0031 (2013.01); H01J 49/004 (2013.01); H01J 49/0045 (2013.01); H01J 49/10 (2013.01); G01N 33/48 (2013.01); H01J 49/00 (2013.01); Y10T 436/17 (2015.01); Y10T 436/24 (2015.01); Y10T 436/25125 (2015.01); Y10T 436/25375 (2015.01)] 9 Claims
 
1. A method for determining an amount of endoxifen and N-desmethyl-4′-hydroxy tamoxifen in a sample by a single mass spectrometry assay, the method comprising:
purifying the sample by liquid chromatography;
ionizing the endoxifen and N-desmethyl-4′-hydroxy tamoxifen in the sample to produce one or more ions detectable by mass spectrometry; and
detecting an amount of the one or more ion(s) by mass spectrometry;
wherein:
the sample is a human sample;
the amount of the one or more ion(s) detected is related to the amount of each of endoxifen and N-desmethyl-4′-hydroxy tamoxifen in the sample; and
the method has a limit of quantitation of less than or equal to 0.4 ng/ml.