Semaglutide impurity profile
Every named species the index has reported alongside Semaglutide, 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.
Median total impurities
1.13%
n=926
Median largest single
0.62%
n=926
Worst single observed
2.23%
n=926
Named species observed
8 / 8
n=8
| Named species | ΔRT (min) | Δ mass (Da) | Seen in | Median % area | Max % area |
|---|---|---|---|---|---|
| des-AEEA semaglutide (−145 Da) | -0.82 | -145.074 | 80% | 0.18 | 2.23 |
| [D-Aib8]-diastereomer | -0.24 | mass-identical | 80% | 0.18 | 2.11 |
| C18 diacid mono-ester | +1.36 | +14.016 | 75% | 0.10 | 1.70 |
| deamidated (Asn→Asp, +1 Da) | -0.51 | +0.984 | 72% | 0.10 | 2.18 |
| des-His1 truncate (−137 Da) | -1.14 | -137.059 | 69% | 0.07 | 1.85 |
| Met(O) sulfoxide (+16 Da) | -0.68 | +15.995 | 56% | 0.07 | 1.92 |
| tBu-protected residual (+56 Da) | +2.05 | +56.063 | 47% | 0.06 | 1.29 |
| semaglutide dimer | +3.71 | +4111.052 | 30% | 0.07 | 1.08 |
des-AEEA semaglutide (−145 Da)
- Retention offset from the main peak
- -0.82 min on RG-2
- Mass difference
- -145.074 Da
- Reported in
- 744 of 926 records (80 %)
- Level when reported
- median 0.18 %, max 2.23 %
- Resolution requirement
- Baseline-resolved on the reference method.
[D-Aib8]-diastereomer
- Retention offset from the main peak
- -0.24 min on RG-2
- Mass difference
- mass-identical — chromatography only
- Reported in
- 738 of 926 records (80 %)
- Level when reported
- median 0.18 %, max 2.11 %
- Resolution requirement
- A gradient long enough to separate it. No mass spectrometer will.
C18 diacid mono-ester
- Retention offset from the main peak
- +1.36 min on RG-2
- Mass difference
- +14.016 Da
- Reported in
- 696 of 926 records (75 %)
- Level when reported
- median 0.10 %, max 1.70 %
- Resolution requirement
- Baseline-resolved on the reference method.
deamidated (Asn→Asp, +1 Da)
- Retention offset from the main peak
- -0.51 min on RG-2
- Mass difference
- +0.984 Da
- Reported in
- 670 of 926 records (72 %)
- Level when reported
- median 0.10 %, max 2.18 %
- Resolution requirement
- Baseline-resolved on the reference method.
des-His1 truncate (−137 Da)
- Retention offset from the main peak
- -1.14 min on RG-2
- Mass difference
- -137.059 Da
- Reported in
- 643 of 926 records (69 %)
- Level when reported
- median 0.07 %, max 1.85 %
- Resolution requirement
- Baseline-resolved on the reference method.
Met(O) sulfoxide (+16 Da)
- Retention offset from the main peak
- -0.68 min on RG-2
- Mass difference
- +15.995 Da
- Reported in
- 518 of 926 records (56 %)
- Level when reported
- median 0.07 %, max 1.92 %
- Resolution requirement
- Baseline-resolved on the reference method.
tBu-protected residual (+56 Da)
- Retention offset from the main peak
- +2.05 min on RG-2
- Mass difference
- +56.063 Da
- Reported in
- 436 of 926 records (47 %)
- Level when reported
- median 0.06 %, max 1.29 %
- Resolution requirement
- Baseline-resolved on the reference method.
semaglutide dimer
- Retention offset from the main peak
- +3.71 min on RG-2
- Mass difference
- +4111.052 Da
- Reported in
- 274 of 926 records (30 %)
- Level when reported
- median 0.07 %, max 1.08 %
- 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.
- side-chain amide hydrolysis at the AEEA-AEEA linker under alkaline stress
- Asn26 deamidation accelerating above pH 8
- fibrillation on agitation of reconstituted material held above 25 °C