AssayIndex

AX-2025-019112

Retatrutide · 10 mg declared · GenScript Biotech Corporation · lot GSP-2411-B2857

PASSVERIFIED
Report ID
AX-2025-019112
Compound
Retatrutide
Compound class
Incretin analogues and co-agonists
Supplier
GSP — GenScript Biotech Corporation
Batch / lot
GSP-2411-B2857
Declared label claim
10mg
Laboratory
Nordanalyt Laboratories
Assay date
25 Apr 2025
Submitted
18 May 2025
Quarter
2025-Q2
Submitter
bland_altman
Sample provenance
Buyer-sourced
Section 1

Results

Measured against the index acceptance specification for the incretin analogues and co-agonists class. A specification is a decision the index made; a result is a measurement. See where each threshold came from.

ParameterMethodResultUnitIndex spec
PurityRP-HPLC, 35 min gradient, 214 nm98.34% area≥ 96.5PASS
Total impuritiesRP-HPLC, sum of reported peaks1.66% area≤ 3.5PASS
Largest single impurityRP-HPLC — C18 diacid regioisomer0.97% area≤ 1.00PASS
Identity — theoretical monoisotopic masscalculated from molecular formula4728.4871Da—NOT TESTED
Identity — observed monoisotopic massLC-MS, high resolution (ESI-TOF/QTOF)4728.5117Da—NOT TESTED
Mass accuracyobserved vs theoretical+5.2ppm± 15PASS
Total peptide contentby difference from the gravimetric mass balance84.49%w/w—NOT TESTED
Target-compound contenttotal peptide content × purity83.09%w/w—NOT TESTED
Gross fill (as weighed)five-place balance, under nitrogen11.38mg10 mg declaredNOT TESTED
Recovered target peptidegross fill × target content9.456mg10 mg claimNOT TESTED
Recovery against label claimrecovered ÷ claim94.6%90.0 – 110.0PASS
Water contentKarl Fischer, coulometric, duplicate7.67%≤ 8.0PASS
Counter-ion (TFA)anion-exchange ion chromatography7.07%≤ 12.0PASS
Residual solvent + inorganic residueestimated — see /methods/residual-solvents-q3c/0.77%—NOT TESTED
Endotoxinnot ordered on this submissionnot determined—≤ 5.0NOT TESTED
Sterilitynot ordered on this submissionnot determined—no growthNOT TESTED
Appearancevisual, diffuse light, black and white backgroundWhite cake, partially collapsed—white to off-white intact cakeFAIL
Reconstitution clarityreconstituted per submitter procedureClear, colourless, no visible particulates—clear, no visible particulatesPASS
pH (reconstituted, 1 mg/mL)potentiometric, two-point calibration4.59—2.5 – 8.0PASS
Retention time (observed)RP-HPLC, 35 min gradient23.94min23.89 ± 0.50 (normalised)PASS
Peak asymmetry (10 % height)Ph. Eur. 2.2.461.10—0.80 – 1.50PASS
Plate count, main peakN = 5.54 (t/w½)²48,763—≥ 20,000PASS
Resolution to nearest impurityvs [D-Aib2]-diastereomer0.58—no index criterionREPORTED
Section 2

Chromatogram and peak integration

The figure is drawn from the table. It is not an independent illustration — if a number in the table changed, the trace would change with it.

01000200030014001 Retatrutide23.94 min · 98.34 % 24.6221.70 same trace · ×50 vertical expansion, baseline-corrected · main peak off-scale reporting threshold 0.05 % area 0510152025303540 Retention time (min) Response (mAU)
Figure 1. RP-HPLC trace, 35 min gradient, 214 nm. Drawn from the peak-integration table below: peak positions are the reported retention times, peak areas are the reported area percentages, peak widths follow the reported plate count of 48,763, and skew follows the reported asymmetry factor of 1.10. Baseline noise is seeded from the report ID and is illustrative. The lower panel is the same trace at a stated vertical expansion with the slow gradient drift subtracted, because at full scale a 0.97 % impurity against a 98.34 % main peak is a line two pixels tall; the main peak runs off-scale there by design.
#PeakRTArea (µV·s)% areaΔ mass (Da)
1Retatrutide — main peak23.944,779,62998.34—
2C18 diacid regioisomer24.6247,1450.970.000
3truncated (5-39)21.7017,0110.35-428.201
4[D-Aib2]-diastereomer23.6811,1790.230.000
5aspartimide (−18 Da)24.772,4300.05-18.011
6des-Aib20 analogue23.431,4580.03-85.053
7oxidised Trp (+16 Da)23.171,4580.03+15.995
Closure check — purity + Σ impurities 100.00CLOSES

Reporting threshold 0.05 % area. Peaks below it are not reported and are therefore excluded from the total, which overstates purity by their sum — see peak integration.

Section 3

Mass spectrum and identity

Theoretical monoisotopic mass 4728.4871 Da, computed from C221H342N46O68. All ppm figures on this site are against monoisotopic values — see why that matters.

0255075100550750950115013501550 [M+5H]5+946.71[M+6H]6+789.09[M+4H]4+1183.14 m/z Relative abundance (%)
Figure 2. ESI charge-state envelope, high-resolution instrument. Sticks are placed at m/z = (M + z × 1.007276)/z for the observed neutral mass of 4728.5117 Da. Sodium (+21.982/z) and potassium (+37.956/z) adducts are shown where the parent charge state exceeds 25 % relative abundance; they are adducts of the same molecule and are not impurities.
ChargeTheoretical m/zObserved m/zΔ m/zRel. abundance (%)
7+676.5054676.50890.00358.4
6+789.0885789.09260.004150.8
5+946.7047946.70960.0049100.0
4+1183.12911183.13520.006150.5
3+1577.16961577.17780.00828.2
Section 4

Gravimetric mass balance

Water, counter-ion, residual and total peptide content are exhaustive and mutually exclusive categories. They must account for 100 % of the cake mass. The index closes this to within 0.02 pp and the build asserts it.

ComponentDetermination%w/w of cake
WaterKarl Fischer7.67
Counter-ion (TFA)ion chromatography7.07
Residual solvent + inorganic residueestimated0.77
Total peptide contentby difference84.49
Total100.00 CLOSES

Supplier certificate, as declared

The supplier's own figures for this lot, beside the independent measurement. Divergence is assessed against the batch median, not against this single report — see rule AX-R05.

FigureSupplier COAThis reportIndex note
Purity (% area)98.2598.34divergence +0.42 pp vs batch median
Total impurities (% area)1.751.66
Largest single impurity (% area)0.600.97
Water (%)5.37.67
Counter-ion (%)not stated7.07
Peptide content (%w/w)not stated84.49
Endotoxin (EU/mg)not statednot determined
Method stated on certificateYES—column, gradient and wavelength given
Section 5

Provenance and caveats

Where a sample came from changes the weight of the evidence. The index treats it as a first-class field.

Sample provenance
Buyer-sourced
Evidentiary weight
Strongest available evidence in this index.
Chain of custody
Retail purchase → third-party forwarder (27 d) → laboratory (courier, cold pack, 7 d) → assay.
Assay date
25 Apr 2025
Submitted to the index
18 May 2025
Laboratory
Nordanalyt Laboratories, Uppsala, Sweden
Method basis
35 min gradient · high-resolution MS
Verification status
VERIFIED
Section 6

Annotations 1

Signed technical comments from index contributors. Not a discussion forum — annotations question or contextualise the result, and the data team replies where a reply is warranted.

deamidation_rate
Deamidation adds one dalton, which at this mass is close to the resolution of the question rather than to the resolution of the instrument. The named-impurity table is the better place to look for it.
Section 7

Related records

Same batch — lot GSP-2411-B2857 n=16

ReportLotLabQuarterPurity %Water %Recovery %ProvenanceFlagsResult
AX-2025-019101GSP-2411-B2857Medutest2025-Q298.367.25—Buyer-sourced0PASS
AX-2025-019102GSP-2411-B2857Janoshik2025-Q298.037.2298.7Buyer-sourced0PASS
AX-2025-019103GSP-2411-B2857Janoshik2025-Q297.397.16105.7Buyer-sourced0PASS
AX-2025-019104GSP-2411-B2857Janoshik2025-Q297.967.23—Buyer-sourced0PASS
AX-2025-019105GSP-2411-B2857PeptideMeter2025-Q297.717.5994.6Buyer-sourced0PASS
AX-2025-019106GSP-2411-B2857Janoshik2025-Q297.587.19104.1Buyer-sourced0PASS
AX-2025-019107GSP-2411-B2857Medutest2025-Q298.127.94—Buyer-sourced1FAIL
AX-2025-019108GSP-2411-B2857VendorInvestigate2025-Q297.876.8797.9Buyer-sourced0PASS
AX-2025-019109GSP-2411-B2857Kestrel2025-Q297.987.08—Buyer-sourced1FAIL
AX-2025-019110GSP-2411-B2857Janoshik2025-Q297.736.55—Buyer-sourced0PASS
AX-2025-019111GSP-2411-B2857PeptideMeter2025-Q297.797.87102.1Buyer-sourced0PASS
AX-2025-019113GSP-2411-B2857Janoshik2025-Q297.627.50—Buyer-sourced0PASS
AX-2025-019114GSP-2411-B2857Janoshik2025-Q297.797.41102.5Buyer-sourced0PASS
AX-2025-019115GSP-2411-B2857PeptideMeter2025-Q297.497.38—Buyer-sourced0PASS
AX-2025-019116GSP-2411-B2857Kestrel2025-Q297.997.19100.2Buyer-sourced0PASS

Cross-sections

Other recent Retatrutide records in the index.
ReportSupplierLotLabQuarterPurity %Water %Recovery %ProvenanceFlagsResult
AX-2026-042437HomopeptideHOMO-2605-V4718Nordanalyt2026-Q398.683.67102.8Buyer-sourced0PASS
AX-2026-043095KPKP-2607-H5774Janoshik2026-Q395.815.48105.2Buyer-sourced0FAIL
AX-2026-042282TFCTFC-2608-J1156Janoshik2026-Q398.544.27—Buyer-sourced0PASS
AX-2026-043094KPKP-2607-H5774PeptideMeter2026-Q396.326.40—Buyer-sourced0FAIL
AX-2026-042441HomopeptideHOMO-2605-V4718Medutest2026-Q398.934.22—Buyer-sourced0PASS
AX-2026-041427QYBQYB-2604-B4920PeptideMeter2026-Q397.932.45101.7Buyer-sourced0PASS
AX-2026-041786ASYASY-{CAT}-2288VendorInvestigate2026-Q398.786.59—Buyer-sourced0PASS
AX-2026-041428QYBQYB-2604-B4920Janoshik2026-Q398.353.20—Laboratory-retained0PASS
Other recent GSP records in the index.
ReportCompoundLotLabQuarterPurity %Water %Recovery %ProvenanceFlagsResult
AX-2026-041831SurvodutideGSP-2603-E3156Kestrel2026-Q399.915.5093.2Buyer-sourced0PASS
AX-2026-041836SurvodutideGSP-2603-E3156Janoshik2026-Q398.655.3490.3Buyer-sourced0PASS
AX-2026-041837SurvodutideGSP-2603-E3156Janoshik2026-Q398.335.37—Buyer-sourced0PASS
AX-2026-041833SurvodutideGSP-2603-E3156Janoshik2026-Q398.084.9199.3Buyer-sourced0PASS
AX-2026-041832SurvodutideGSP-2603-E3156VendorInvestigate2026-Q398.015.1499.5Buyer-sourced0PASS
AX-2026-041835SurvodutideGSP-2603-E3156Nordanalyt2026-Q398.345.7489.0Buyer-sourced1MARGINAL
AX-2026-041834SurvodutideGSP-2603-E3156VendorInvestigate2026-Q397.925.95—Buyer-sourced0PASS
AX-2026-041838SurvodutideGSP-2603-E3156PeptideMeter2026-Q398.305.01102.4Buyer-sourced0PASS