AX-2024-005251 · Selank · WXT lot WXT-2406-W3910

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, 30 min gradient, 214 nm	99.79	% area	≥ 99.0	PASS
Total impurities	RP-HPLC, sum of reported peaks	0.21	% area	≤ 1.0	PASS
Largest single impurity	RP-HPLC — diketopiperazine (−18 Da)	0.13	% area	≤ 1.00	PASS
Identity — theoretical monoisotopic mass	calculated from molecular formula	751.4402	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, high resolution (ESI-TOF/QTOF)	751.4367	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	-4.6	ppm	± 15	PASS
Total peptide content	by difference from the gravimetric mass balance	83.34	%w/w	—	NOT TESTED
Target-compound content	total peptide content × purity	83.16	%w/w	—	NOT TESTED
Gross fill (as weighed)	five-place balance, under nitrogen	12.06	mg	10 mg declared	NOT TESTED
Recovered target peptide	gross fill × target content	10.029	mg	10 mg claim	NOT TESTED
Recovery against label claim	recovered ÷ claim	100.3	%	90.0 – 110.0	PASS
Water content	Karl Fischer, coulometric, duplicate	10.08	%	≤ 12.0	PASS
Counter-ion (acetate)	anion-exchange ion chromatography	5.83	%	≤ 10.0	PASS
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.75	%	—	NOT TESTED
Endotoxin	kinetic chromogenic LAL	0.47	EU/mg	≤ 5.0	PASS
Sterility	not ordered on this submission	not determined	—	no growth	NOT TESTED
Appearance	visual, diffuse light, black and white background	White to pale-yellow 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	4.64	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 30 min gradient	5.66	min	6.42 ± 0.25 (normalised)	FAIL
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.05	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	95,423	—	≥ 20,000	PASS
Resolution to nearest impurity	vs diketopiperazine (−18 Da)	2.40	—	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, 30 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 95,423, and skew follows the reported asymmetry factor of 1.05. 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 0.13 % impurity against a 99.79 % 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	5.66	4,850,103	99.79	—
2	diketopiperazine (−18 Da)	5.84	6,318	0.13	-18.011
3	tuftsin fragment (−417 Da)	5.04	2,430	0.05	-417.235
4	des-Thr (−101 Da)	5.40	1,458	0.03	-101.048
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, high-resolution instrument. Sticks are placed at m/z = (M + z × 1.007276)/z for the observed neutral mass of 751.4367 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	376.7256	-0.0018	57.0
1+	752.4475	752.4440	-0.0035	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	10.08
Counter-ion (acetate)	ion chromatography	5.83
Residual solvent + inorganic residue	estimated	0.75
Total peptide content	by difference	83.34
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)	99.88	99.79	divergence +0.30 pp vs batch median
Total impurities (% area)	0.12	0.21
Largest single impurity (% area)	0.05	0.13
Water (%)	8.3	10.08
Counter-ion (%)	not stated	5.83
Peptide content (%w/w)	not stated	83.34
Endotoxin (EU/mg)	0.23	0.47
Method stated on certificate	NO	—	no method section — the result cannot be reconciled against any other

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, 11 d) → assay. Submitter did not handle the vial.
Assay date: 14 Aug 2024
Submitted to the index: 25 Aug 2024
Laboratory: Janoshik Analytical, Ostrava, Czechia
Method basis: 30 min gradient · high-resolution MS
Verification status: VERIFIED

What this report does not establish

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 3

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.

uncertainty_budget25 Aug 2024

Expanded uncertainty on a well-resolved main peak is about ±0.48 pp at 95 % confidence. 99.79 % should be read as a band, and the band is still comfortably above the class specification.

median_not_mean25 Aug 2024

One result at the top of the distribution should not move anybody's estimate much on its own. Purity distributions are compressed at the top and long-tailed at the bottom, so the informative observations are the low ones.

esi_tof25 Aug 2024

The observed monoisotopic mass on this record reconciles with the theoretical value to four decimal places, which is the arithmetic the index re-derives in its own build check rather than accepting from the report.

Section 7

Related records

Same batch — lot WXT-2406-W3910 n=2

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2024-005250	WXT-2406-W3910	Kestrel	2024-Q3	99.37	9.27	—	Buyer-sourced	1	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-2026-042858	GGPeps	GGPE-2603-J2447	VendorInvestigate	2026-Q3	98.87	8.85	99.4	Buyer-sourced	0	FAIL
AX-2026-042859	GGPeps	GGPE-2603-J2447	PeptideMeter	2026-Q3	98.92	9.48	103.5	Buyer-sourced	0	FAIL
AX-2026-041759	TFS	TFS-{CAT}-1712	Janoshik	2026-Q2	99.93	8.13	102.2	Buyer-sourced	0	PASS
AX-2026-042912	GGPeps	GGPE-2601-J3130	Janoshik	2026-Q2	99.75	9.44	89.7	Buyer-sourced	1	MARGINAL
AX-2026-041760	TFS	TFS-{CAT}-1712	Janoshik	2026-Q2	99.82	7.70	—	Buyer-sourced	0	PASS
AX-2026-041752	TFS	TFS-{CAT}-1712	Medutest	2026-Q2	99.63	7.43	—	Buyer-sourced	1	FAIL
AX-2026-042915	GGPeps	GGPE-2601-J3130	PeptideMeter	2026-Q2	99.53	10.03	—	Buyer-sourced	0	PASS
AX-2026-042910	GGPeps	GGPE-2601-J3130	VendorInvestigate	2026-Q2	99.62	9.21	105.0	Buyer-sourced	0	PASS

Other recent WXT records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-043376	Semaglutide	WXT-2604-C3248	Janoshik	2026-Q3	97.08	4.22	—	Buyer-sourced	1	MARGINAL
AX-2026-043429	L-Glutathione (reduced)	WXT-2605-B3833	Nordanalyt	2026-Q3	98.48	6.58	96.9	Supplier-supplied	1	FAIL
AX-2026-043347	Leuprolide	WXT-2604-K2596	PeptideMeter	2026-Q3	99.16	5.99	93.6	Buyer-sourced	0	PASS
AX-2026-043353	Leuprolide	WXT-2604-K2596	Janoshik	2026-Q3	99.19	4.90	95.3	Laboratory-retained	0	PASS
AX-2026-043345	Leuprolide	WXT-2604-K2596	Janoshik	2026-Q3	98.93	5.28	—	Buyer-sourced	0	PASS
AX-2026-043424	L-Glutathione (reduced)	WXT-2605-B3833	PeptideMeter	2026-Q3	98.37	6.86	—	Buyer-sourced	0	FAIL
AX-2026-043374	Semaglutide	WXT-2604-C3248	Janoshik	2026-Q3	97.00	3.56	—	Buyer-sourced	1	MARGINAL
AX-2026-043377	Semaglutide	WXT-2604-C3248	PeptideMeter	2026-Q3	97.20	4.08	—	Buyer-sourced	1	MARGINAL