AX-2024-005432 · Selank · WXT lot WXT-2406-W5390

Section 1

Results

Measured against the index acceptance specification for the neuroactive and cognitive 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, 25 min gradient, 214 nm	99.35	% area	≥ 99.0	PASS
Total impurities	RP-HPLC, sum of reported peaks	0.65	% area	≤ 1.0	PASS
Largest single impurity	RP-HPLC — diketopiperazine (−18 Da)	0.27	% area	≤ 1.00	PASS
Identity — theoretical monoisotopic mass	calculated from molecular formula	751.4402	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, unit resolution (single quadrupole)	751.4505	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	+13.7	ppm	± 15	PASS
Total peptide content	by difference from the gravimetric mass balance	84.20	%w/w	—	NOT TESTED
Target-compound content	total peptide content × purity	83.65	%w/w	—	NOT TESTED
Gross fill (as weighed)	five-place balance, under nitrogen	11.48	mg	10 mg declared	NOT TESTED
Recovered target peptide	gross fill × target content	9.603	mg	10 mg claim	NOT TESTED
Recovery against label claim	recovered ÷ claim	96.0	%	90.0 – 110.0	PASS
Water content	Karl Fischer, coulometric, duplicate	9.64	%	≤ 12.0	PASS
Counter-ion (acetate)	anion-exchange ion chromatography	5.62	%	≤ 10.0	PASS
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.54	%	—	NOT TESTED
Endotoxin	not ordered on this submission	not determined	—	≤ 5.0	NOT TESTED
Sterility	not ordered on this submission	not determined	—	no growth	NOT TESTED
Appearance	visual, diffuse light, black and white background	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	4.24	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 25 min gradient	5.44	min	5.44 ± 0.25 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.03	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	49,739	—	≥ 20,000	PASS
Resolution to nearest impurity	vs diketopiperazine (−18 Da)	1.50	—	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, 25 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 49,739, and skew follows the reported asymmetry factor of 1.03. 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 0.27 % impurity against a 99.35 % 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	Selank — main peak	5.44	4,828,718	99.35	—
2	diketopiperazine (−18 Da)	5.59	13,123	0.27	-18.011
3	des-Thr (−101 Da)	5.22	8,749	0.18	-101.048
4	tuftsin fragment (−417 Da)	4.92	6,318	0.13	-417.235
5	acetyl adduct (+42 Da)	5.72	3,402	0.07	+42.011
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 751.4402 Da, computed from C33H57N11O9. All ppm figures on this site are against monoisotopic values — see why that matters.

Figure 2. ESI charge-state envelope, unit-resolution instrument. Sticks are placed at m/z = (M + z × 1.007276)/z for the observed neutral mass of 751.4505 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 (%)
2+	376.7274	376.7325	0.0051	54.1
1+	752.4475	752.4578	0.0103	100.0

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	9.64
Counter-ion (acetate)	ion chromatography	5.62
Residual solvent + inorganic residue	estimated	0.54
Total peptide content	by difference	84.20
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)	99.64	99.35	divergence +0.63 pp vs batch median
Total impurities (% area)	0.36	0.65
Largest single impurity (% area)	0.22	0.27
Water (%)	8.6	9.64
Counter-ion (%)	not stated	5.62
Peptide content (%w/w)	not stated	84.20
Endotoxin (EU/mg)	0.24	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, 4 d) → assay. Submitter did not handle the vial.
Assay date: 28 Aug 2024
Submitted to the index: 12 Sep 2024
Laboratory: Medutest, Ljubljana, Slovenia
Method basis: 25 min gradient · unit-resolution MS
Verification status: IDENTITY CONSISTENT

What this report does not establish

That the compound is not a near-isobaric alternative. Identity was confirmed at unit mass resolution, which cannot exclude species differing by 1 or 2 Da. The specific alternatives not excluded are named in the identity block above.
That the material is free of bacterial endotoxin. Endotoxin was not measured. No chromatographic result bears on it.
That the material is sterile. Sterility was not tested.
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 WXT-2406-W5390 n=10

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Result
AX-2024-005428	WXT-2406-W5390	Janoshik	2024-Q3	98.87	9.68	—	Supplier-supplied	FAIL
AX-2024-005429	WXT-2406-W5390	Janoshik	2024-Q3	98.97	9.91	—	Buyer-sourced	FAIL
AX-2024-005430	WXT-2406-W5390	Janoshik	2024-Q3	98.54	9.53	101.1	Supplier-supplied	FAIL
AX-2024-005431	WXT-2406-W5390	Janoshik	2024-Q3	99.61	9.90	92.2	Supplier-supplied	PASS
AX-2024-005433	WXT-2406-W5390	Janoshik	2024-Q3	99.65	8.74	99.1	Supplier-supplied	PASS
AX-2024-005434	WXT-2406-W5390	Medutest	2024-Q3	99.05	9.66	94.8	Buyer-sourced	PASS
AX-2024-005435	WXT-2406-W5390	Janoshik	2024-Q3	99.07	9.06	104.1	Supplier-supplied	PASS
AX-2024-005436	WXT-2406-W5390	VendorInvestigate	2024-Q3	98.60	9.32	98.6	Buyer-sourced	FAIL
AX-2024-005437	WXT-2406-W5390	VendorInvestigate	2024-Q3	98.60	9.34	—	Buyer-sourced	FAIL

Batch rollup and reproducibility assessment →

Cross-sections

Other recent Selank records in the index.
Report	Supplier	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-042737	GGPeps	GGPE-2603-J9708	Janoshik	2026-Q3	98.40	9.14	97.4	Buyer-sourced	0	FAIL
AX-2026-042804	GGPeps	GGPE-2602-G2056	Janoshik	2026-Q3	98.50	7.97	—	Supplier-supplied	0	FAIL
AX-2026-042803	GGPeps	GGPE-2602-G2056	Janoshik	2026-Q3	98.48	8.01	—	Laboratory-retained	1	FAIL
AX-2026-042802	GGPeps	GGPE-2602-G2056	Janoshik	2026-Q3	98.74	7.09	96.0	Supplier-supplied	0	FAIL
AX-2026-042796	GGPeps	GGPE-2602-G2056	Janoshik	2026-Q3	98.26	7.56	97.5	Buyer-sourced	0	FAIL
AX-2026-042797	GGPeps	GGPE-2602-G2056	Medutest	2026-Q3	98.46	7.92	—	Buyer-sourced	0	FAIL
AX-2026-042743	GGPeps	GGPE-2603-J9708	Medutest	2026-Q3	99.59	9.37	—	Supplier-supplied	0	PASS
AX-2026-042799	GGPeps	GGPE-2602-G2056	Nordanalyt	2026-Q3	98.77	8.33	—	Supplier-supplied	0	FAIL

Other recent WXT records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-043488	Pramlintide	WXT-2603-D6052	Janoshik	2026-Q3	97.87	4.37	—	Supplier-supplied	1	MARGINAL
AX-2026-043406	Semaglutide	WXT-2604-C4728	Janoshik	2026-Q3	97.24	4.65	—	Supplier-supplied	1	MARGINAL
AX-2026-043421	Sermorelin	WXT-2608-P4867	Janoshik	2026-Q3	98.15	3.09	—	Supplier-supplied	0	PASS
AX-2026-043420	Sermorelin	WXT-2608-P4867	Medutest	2026-Q3	98.62	3.07	96.4	Supplier-supplied	0	PASS
AX-2026-043423	Sermorelin	WXT-2608-P4867	Janoshik	2026-Q3	98.28	3.86	98.5	Buyer-sourced	0	PASS
AX-2026-043401	Semaglutide	WXT-2604-C4728	Medutest	2026-Q3	97.70	4.78	91.5	Supplier-supplied	1	MARGINAL
AX-2026-043400	Semaglutide	WXT-2604-C4728	Nordanalyt	2026-Q3	96.86	4.11	106.4	Laboratory-retained	1	FAIL
AX-2026-043422	Sermorelin	WXT-2608-P4867	Medutest	2026-Q3	98.35	3.59	—	Supplier-supplied	1	MARGINAL