AX-2026-042526 · PEG-MGF · ERP lot ERP-2509-K6500

Section 1

Results

Measured against the index acceptance specification for the growth-hormone axis peptides class. A specification is a decision the index made; a result is a measurement. See where each threshold came from.

Parameter	Method	Result	Unit	Index spec
Purity	RP-HPLC, 28 min gradient, 214 nm	98.36	% area	≥ 92.0	PASS
Total impurities	RP-HPLC, sum of reported peaks	1.64	% area	≤ 8.0	PASS
Largest single impurity	RP-HPLC — free MGF (unconjugated)	0.85	% area	≤ 1.00	PASS
Identity — theoretical monoisotopic mass	calculated from molecular formula	7894.0000	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, high resolution (ESI-TOF/QTOF)	7893.9637	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	-4.6	ppm	± 15	PASS
Total peptide content	by difference from the gravimetric mass balance	92.91	%w/w	—	NOT TESTED
Target-compound content	total peptide content × purity	91.39	%w/w	—	NOT TESTED
Gross fill (as weighed)	five-place balance, under nitrogen	5.31	mg	5 mg declared	NOT TESTED
Recovered target peptide	gross fill × target content	4.853	mg	5 mg claim	NOT TESTED
Recovery against label claim	recovered ÷ claim	97.1	%	90.0 – 110.0	PASS
Water content	Karl Fischer, coulometric, duplicate	4.87	%	≤ 9.0	PASS
Counter-ion (acetate)	anion-exchange ion chromatography	1.58	%	≤ 12.0	PASS
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.64	%	—	NOT TESTED
Endotoxin	not ordered on this submission	not determined	—	≤ 5.0	NOT TESTED
Sterility	membrane filtration, USP <71>, 14 d	No growth at 14 d	—	no growth	PASS
Appearance	visual, diffuse light, black and white background	Off-white lyophilised cake, intact	—	white to off-white intact cake	PASS
Reconstitution clarity	reconstituted per submitter procedure	Clear, colourless, no visible particulates	—	clear, no visible particulates	PASS
pH (reconstituted, 1 mg/mL)	potentiometric, two-point calibration	5.36	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 28 min gradient	16.19	min	16.18 ± 0.80 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.25	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	34,767	—	≥ 20,000	PASS
Resolution to nearest impurity	vs hydrolysed linker	1.89	—	no index criterion	REPORTED

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.

Figure 1. RP-HPLC trace, 28 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 34,767, and skew follows the reported asymmetry factor of 1.25. 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 0.85 % impurity against a 98.36 % main peak is a line two pixels tall; the main peak runs off-scale there by design.

#	Peak	RT	Area (µV·s)	% area	Δ mass (Da)
1	PEG-MGF — main peak	16.19	4,780,601	98.36	—
2	free MGF (unconjugated)	10.94	41,313	0.85	-5007.488
3	free mPEG	18.45	20,899	0.43	-2886.512
4	di-PEGylated species	17.92	8,749	0.18	+5000.000
5	hydrolysed linker	15.52	8,749	0.18	+18.011
Closure check — purity + Σ impurities				100.00	CLOSES

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 7894.0000 Da, computed from conjugate (24-mer + 5 kDa mPEG). All ppm figures on this site are against monoisotopic values — see why that matters.

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 7893.9637 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.

Charge	Theoretical m/z	Observed m/z	Δ m/z	Rel. abundance (%)
10+	790.4073	790.4036	-0.0037	8.0
9+	878.1184	878.1144	-0.0040	51.0
8+	987.7573	987.7527	-0.0046	100.0
7+	1128.7216	1128.7164	-0.0052	53.1
6+	1316.6739	1316.6679	-0.0060	8.2

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.

Component	Determination	%w/w of cake
Water	Karl Fischer	4.87
Counter-ion (acetate)	ion chromatography	1.58
Residual solvent + inorganic residue	estimated	0.64
Total peptide content	by difference	92.91
Total		100.00 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.

Figure	Supplier COA	This report	Index note
Purity (% area)	98.5	98.36	divergence +0.42 pp vs batch median
Total impurities (% area)	not stated	1.64
Largest single impurity (% area)	not stated	0.85
Water (%)	not stated	4.87
Counter-ion (%)	3.0	1.58
Peptide content (%w/w)	97.5	92.91
Endotoxin (EU/mg)	not stated	not determined
Method stated on certificate	YES	—	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: Supplier-supplied
Evidentiary weight: Weaker evidence. Read with the caveat below.
Chain of custody: Supplier despatch → laboratory direct (courier, cold pack, 6 d) → assay. Submitter did not handle the vial.
Assay date: 06 Mar 2026
Submitted to the index: 30 Mar 2026
Laboratory: PeptideMeter, Tallinn, Estonia
Method basis: 28 min gradient · high-resolution MS
Verification status: VERIFIED

What this report does not establish

That the material is free of bacterial endotoxin. Endotoxin was not measured. No chromatographic result bears on it.
That any other vial in the same lot has the same composition. One vial was tested. Within-lot vial-to-vial variation in this index has a median of 0.28 pp and a 90th percentile of 0.74 pp.
That any other lot from the same supplier has the same composition. Batch-to-batch variation is larger than within-batch variation for every supplier here.
That the material is suitable for administration to a human or an animal. These are research compounds. No result on this site is a safety assessment and the index takes no position on use.
That the material was manufactured by the supplier that sold it. Contract synthesis is normal in this market and twenty-nine batches in the index fingerprint to a bulk from a different company than the one named on the label.

Section 6

Annotations

No annotations on this record. Annotations are short signed technical comments from index contributors; see how to contribute.

Section 7

Related records

Same batch — lot ERP-2509-K6500 n=3

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-042527	ERP-2509-K6500	Kestrel	2026-Q1	97.92	4.96	—	Supplier-supplied	1	MARGINAL
AX-2026-042528	ERP-2509-K6500	Janoshik	2026-Q1	98.08	5.50	89.3	Supplier-supplied	2	MARGINAL

Batch rollup and reproducibility assessment →

Cross-sections

Other recent PEG-MGF records in the index.
Report	Supplier	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-042528	ERP	ERP-2509-K6500	Janoshik	2026-Q1	98.08	5.50	89.3	Supplier-supplied	2	MARGINAL
AX-2026-042527	ERP	ERP-2509-K6500	Kestrel	2026-Q1	97.92	4.96	—	Supplier-supplied	1	MARGINAL
AX-2026-043130	SSA	SSA-2505-U6896	VendorInvestigate	2025-Q4	96.17	2.67	—	Buyer-sourced	0	PASS
AX-2026-043131	SSA	SSA-2505-U6896	Janoshik	2025-Q4	95.81	2.95	96.2	Supplier-supplied	0	PASS
AX-2025-020576	SSA	SSA-2505-U6896	Medutest	2025-Q4	96.30	2.53	—	Supplier-supplied	0	PASS
AX-2025-020575	SSA	SSA-2505-U6896	Medutest	2025-Q4	96.04	2.63	—	Supplier-supplied	1	FAIL
AX-2025-020577	SSA	SSA-2505-U6896	VendorInvestigate	2025-Q4	95.71	2.67	—	Buyer-sourced	0	PASS
AX-2025-020578	SSA	SSA-2505-U6896	Janoshik	2025-Q4	95.55	3.57	—	Buyer-sourced	0	PASS

Other recent ERP records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-042574	TB-500	ERP-2605-S8022	VendorInvestigate	2026-Q3	99.54	2.91	96.4	Buyer-sourced	1	MARGINAL
AX-2026-042535	Tesamorelin	ERP-2604-W7280	Janoshik	2026-Q3	99.19	3.89	92.7	Supplier-supplied	1	MARGINAL
AX-2026-042577	TB-500	ERP-2605-S8022	Janoshik	2026-Q3	99.51	3.45	—	Supplier-supplied	1	MARGINAL
AX-2026-042542	Tesamorelin	ERP-2604-W7280	Janoshik	2026-Q3	98.54	4.58	103.1	Supplier-supplied	2	FAIL
AX-2026-042547	Survodutide	ERP-2605-E7682	PeptideMeter	2026-Q3	98.25	5.44	93.0	Supplier-supplied	1	MARGINAL
AX-2026-042540	Tesamorelin	ERP-2604-W7280	Kestrel	2026-Q3	99.72	3.47	103.2	Supplier-supplied	1	MARGINAL
AX-2026-042575	TB-500	ERP-2605-S8022	Janoshik	2026-Q3	99.93	3.36	95.5	Supplier-supplied	0	PASS
AX-2026-042539	Tesamorelin	ERP-2604-W7280	Janoshik	2026-Q3	98.77	4.30	89.9	Buyer-sourced	2	MARGINAL