AssayIndex
Cross-section

Tirzepatide impurity profile

Every named species the index has reported alongside Tirzepatide, how often, at what level, and what its presence implies about the synthesis or the handling. Reporting threshold is 0.05 % area; anything below it is invisible to this page and is silently added to the main peak.

576 recordsmedian 98.44 %spec 97.0 %
Median total impurities 1.56% n=576
Median largest single 0.79% n=576
Worst single observed 2.72% n=576
Named species observed 8 / 8 n=8
Named speciesΔRT (min)Δ mass (Da)Seen inMedian % areaMax % area
[D-Aib13]-diastereomer-0.19mass-identical85%0.172.72
des-Aib2 analogue-0.35-85.05382%0.182.10
Met(O) sulfoxide (+16 Da)-0.74+15.99576%0.102.19
C20 diacid mono-amide+1.62+0.98469%0.111.66
des-Gly deletion (−57 Da)-0.61-57.02167%0.131.63
trifluoroacetyl adduct (+96 Da)+0.93+95.98266%0.082.37
truncated (3-39)-1.48-222.11264%0.162.08
tirzepatide dimer+3.98+4810.41036%0.050.89

[D-Aib13]-diastereomer

Retention offset from the main peak
-0.19 min on RG-2
Mass difference
mass-identical — chromatography only
Reported in
491 of 576 records (85 %)
Level when reported
median 0.17 %, max 2.72 %
Resolution requirement
A gradient long enough to separate it. No mass spectrometer will.

des-Aib2 analogue

Retention offset from the main peak
-0.35 min on RG-2
Mass difference
-85.053 Da
Reported in
475 of 576 records (82 %)
Level when reported
median 0.18 %, max 2.10 %
Resolution requirement
Baseline-resolved on the reference method.

Met(O) sulfoxide (+16 Da)

Retention offset from the main peak
-0.74 min on RG-2
Mass difference
+15.995 Da
Reported in
437 of 576 records (76 %)
Level when reported
median 0.10 %, max 2.19 %
Resolution requirement
Baseline-resolved on the reference method.

C20 diacid mono-amide

Retention offset from the main peak
+1.62 min on RG-2
Mass difference
+0.984 Da
Reported in
398 of 576 records (69 %)
Level when reported
median 0.11 %, max 1.66 %
Resolution requirement
Baseline-resolved on the reference method.

des-Gly deletion (−57 Da)

Retention offset from the main peak
-0.61 min on RG-2
Mass difference
-57.021 Da
Reported in
384 of 576 records (67 %)
Level when reported
median 0.13 %, max 1.63 %
Resolution requirement
Baseline-resolved on the reference method.

trifluoroacetyl adduct (+96 Da)

Retention offset from the main peak
+0.93 min on RG-2
Mass difference
+95.982 Da
Reported in
382 of 576 records (66 %)
Level when reported
median 0.08 %, max 2.37 %
Resolution requirement
Baseline-resolved on the reference method.

truncated (3-39)

Retention offset from the main peak
-1.48 min on RG-2
Mass difference
-222.112 Da
Reported in
368 of 576 records (64 %)
Level when reported
median 0.16 %, max 2.08 %
Resolution requirement
Baseline-resolved on the reference method.

tirzepatide dimer

Retention offset from the main peak
+3.98 min on RG-2
Mass difference
+4810.410 Da
Reported in
208 of 576 records (36 %)
Level when reported
median 0.05 %, max 0.89 %
Resolution requirement
Baseline-resolved on the reference method.

Degradation pathways

Degradants are a handling finding rather than a synthesis finding. A lot that shipped clean and arrived oxidised tells you about the courier, not the chemist.

  • Met14 oxidation on exposure to peroxide-bearing excipients or air-saturated diluent
  • aspartimide formation at the Asp-Gly motif during synthesis, carried into the lot
  • slow deamidation of Asn in reconstituted material stored above 8 °C