Claims for Patent: 10,241,119

Summary for Patent: 10,241,119

Title:	High sensitivity measurement of parathyroid hormone-related peptide using LC-MS/MS and associated methods
Abstract:	Methods for measuring and analyzing parathyroid hormone-related peptide (PTHrP) using LC-MS/MS, including applications of the methods thereof, are disclosed and discussed. Such methods can include, along with the use of an isotope-labeled internal standard, purifying PTHrP from a biological sample, proteolytically digesting the PTHrP, and measuring specific digestion products using the using LC-MS/MS.
Inventor(s):	Kushnir; Mark M. (Salt Lake City, UT), Rockwood; Alan L. (Riverton, UT), Meikle; A. Wayne (Salt Lake City, UT)
Assignee:	University of Utah Research Foundation (Salt Lake City, UT)
Application Number:	15/150,416
Patent Claims:	1. A method of measuring parathyroid hormone-related peptide (PTHrP) in a biological sample, comprising: preparing the biological sample, wherein preparing further comprises: extracting PTHrP peptides from the biological sample; mixing a PTHrP sequence-derived isotope-labeled internal standard (IS) with the PTHrP peptides; proteolytically digesting the PTHrP peptides and the IS to produce a digestion product; and chromatographically separating the digestion product; and selecting and subjecting a chromatographic peak of the separated digestion product to tandem mass spectrometry to determine the amount of a target peptide, wherein the sequence of the target peptide is YLTQETNK (SEQ ID NO: 002) and the sequence of the IS is YLTQETNK (SEQ ID NO: 002). 2. The method of claim 1, wherein the IS is isotope-labeled in at least one amino acid with at least one .sup.15N. 3. The method of claim 2, wherein the IS is isotope-labeled in all amino acids with .sup.15N at all N atoms. 4. The method of claim 3, wherein mass transitions characteristic of the IS are about m/z 504.fwdarw.729 and about m/z 505.fwdarw.730. 5. The method of claim 3, wherein mass transitions characteristic of the IS are m/z 504.25.fwdarw.729.35 and m/z 504.75.fwdarw.730.25. 6. The method of claim 1, wherein mass transitions characteristic of the target peptide are about m/z 499.fwdarw.720 and about m/z 499.fwdarw.721. 7. The method of claim 1, wherein mass transitions characteristic of the target peptide are m/z 498.75.fwdarw.720.35 and m/z 499.25.fwdarw.721.35. 8. The method of claim 1, wherein the amount of the target peptide is detectable to a sensitivity of at least 0.5 pmol/L. 9. The method of claim 1, wherein preparing the biological sample is performed in 2 hours or less in order to minimize PTHrP degradation. 10. The method of claim 1, performed without a reduction reaction and without an alkylation reaction. 11. The method of claim 1, wherein extracting PTHrP peptides from the biological sample further comprises an affinity extraction selective for PTHrP. 12. The method of claim 11, wherein the affinity extraction is antibody affinity extraction. 13. The method of claim 12, wherein the antibody is coupled to magnetic beads. 14. The method of claim 11, wherein the affinity extraction is aptamer affinity extraction. 15. The method of claim 1, wherein proteolytically digesting is by trypsin digestion. 16. The method of claim 1, wherein the IS comprises at least one amino acid having at least three incorporated isotopic atoms independently selected from the group consisting of .sup.13C, .sup.15N, and .sup.2H.

Details for Patent 10,241,119

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Nps Pharmaceuticals, Inc.	NATPARA	parathyroid hormone	For Injection	125511	01/23/2015		2035-05-07