AX-2026-041394 · Oxytocin · QYB lot QYB-2601-V4429

Section 1

Results

Measured against the index acceptance specification for the hypothalamic and posterior-pituitary hormones 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	99.66	% area	≥ 98.5	PASS
Total impurities	RP-HPLC, sum of reported peaks	0.34	% area	≤ 1.5	PASS
Largest single impurity	RP-HPLC — open-chain (reduced disulfide, +2 Da)	0.17	% area	≤ 1.00	PASS
Identity — theoretical monoisotopic mass	calculated from molecular formula	1006.4365	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, unit resolution (single quadrupole)	1006.4382	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	+1.7	ppm	± 15	PASS
Peptide content	not ordered on this submission	not determined	—	required to check label claim	NOT TESTED
Water content	Karl Fischer, coulometric, duplicate	5.17	%	≤ 8.0	PASS
Counter-ion (acetate)	anion-exchange ion chromatography	3.66	%	≤ 10.0	PASS
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.27	%	—	NOT TESTED
Endotoxin	kinetic chromogenic LAL	0.19	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 lyophilised cake, intact	—	white to off-white intact cake	PASS
Reconstitution clarity	reconstituted per submitter procedure	Clear after 90 s gentle swirling, no particulates	—	clear, no visible particulates	PASS
pH (reconstituted, 1 mg/mL)	potentiometric, two-point calibration	5.46	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 25 min gradient	6.82	min	6.71 ± 0.25 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.02	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	63,738	—	≥ 20,000	PASS
Resolution to nearest impurity	vs deamidated Gln4 (+1 Da)	1.66	—	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 63,738, and skew follows the reported asymmetry factor of 1.02. 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 0.17 % impurity against a 99.66 % 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	Oxytocin — main peak	6.82	4,843,785	99.66	—
2	open-chain (reduced disulfide, +2 Da)	6.39	8,263	0.17	+2.016
3	oxytocin dimer (intermolecular disulfide)	8.64	5,832	0.12	+1004.421
4	deamidated Gln4 (+1 Da)	6.64	1,458	0.03	+0.984
5	Tyr sulfoxide artefact (+16 Da)	6.59	972	0.02	+15.995
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 1006.4365 Da, computed from C43H66N12O12S2. 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 1006.4382 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 (%)
3+	336.4861	336.4867	0.0006	9.3
2+	504.2255	504.2264	0.0009	56.3
1+	1007.4438	1007.4455	0.0017	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.

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)	99.90	99.66	divergence +0.21 pp vs batch median
Total impurities (% area)	0.10	0.34
Largest single impurity (% area)	not stated	0.17
Water (%)	not stated	5.17
Counter-ion (%)	6.3	3.66
Peptide content (%w/w)	89.6	not determined
Endotoxin (EU/mg)	not stated	0.19
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: Buyer-sourced
Evidentiary weight: Strongest available evidence in this index.
Chain of custody: Retail purchase → submitter (−20 °C, 8 d) → laboratory (courier, dry ice, 12 d) → assay.
Assay date: 16 May 2026
Submitted to the index: 30 May 2026
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.
How much of the named compound is in the vial. Peptide content was not determined, so recovered mass cannot be calculated and the label claim cannot be checked.
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.

aib_coupling30 May 2026

Hindered couplings are where a synthesis loses purity, and the deletion products they leave are the first thing to look for. On this record they are not there in quantity.

coa_template30 May 2026

The certificate for QYB-2601-V4429 carries a named related-substances table rather than a totals line. That is what makes 99.66 % checkable against this record instead of merely comparable to it.

quad_unit30 May 2026

The index grades identity by instrument class, not by the ppm figure alone: "confirmed" where the determination was made at high resolution, "consistent with" where it was not. The status block above says which applies to this record, and it is worth reading before the number.

Section 7

Related records

Same batch — lot QYB-2601-V4429 n=12

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-041393	QYB-2601-V4429	PeptideMeter	2026-Q2	99.69	4.63	—	Buyer-sourced	0	PASS
AX-2026-041395	QYB-2601-V4429	Janoshik	2026-Q2	99.93	4.24	101.7	Buyer-sourced	0	PASS
AX-2026-041396	QYB-2601-V4429	PeptideMeter	2026-Q2	99.69	3.97	—	Buyer-sourced	0	PASS
AX-2026-041397	QYB-2601-V4429	Janoshik	2026-Q2	99.62	4.38	102.8	Buyer-sourced	0	PASS
AX-2026-041398	QYB-2601-V4429	Medutest	2026-Q2	99.60	4.73	91.8	Buyer-sourced	0	PASS
AX-2026-041399	QYB-2601-V4429	Medutest	2026-Q2	99.79	4.10	92.5	Buyer-sourced	0	PASS
AX-2026-041400	QYB-2601-V4429	Medutest	2026-Q2	99.51	4.55	—	Buyer-sourced	1	MARGINAL
AX-2026-041401	QYB-2601-V4429	Janoshik	2026-Q2	99.87	4.61	—	Buyer-sourced	0	PASS
AX-2026-041402	QYB-2601-V4429	Janoshik	2026-Q2	99.92	4.90	104.7	Buyer-sourced	0	PASS
AX-2026-041403	QYB-2601-V4429	VendorInvestigate	2026-Q2	99.81	4.82	105.5	Buyer-sourced	0	PASS
AX-2026-041404	QYB-2601-V4429	Medutest	2026-Q2	99.62	5.21	—	Buyer-sourced	0	PASS

Batch rollup and reproducibility assessment →

Cross-sections

Other recent Oxytocin records in the index.
Report	Supplier	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-041398	QYB	QYB-2601-V4429	Medutest	2026-Q2	99.60	4.73	91.8	Buyer-sourced	0	PASS
AX-2026-041400	QYB	QYB-2601-V4429	Medutest	2026-Q2	99.51	4.55	—	Buyer-sourced	1	MARGINAL
AX-2026-041393	QYB	QYB-2601-V4429	PeptideMeter	2026-Q2	99.69	4.63	—	Buyer-sourced	0	PASS
AX-2026-041395	QYB	QYB-2601-V4429	Janoshik	2026-Q2	99.93	4.24	101.7	Buyer-sourced	0	PASS
AX-2026-041950	AMB	AMB-2602-G4870	Janoshik	2026-Q2	99.82	3.21	—	Buyer-sourced	0	PASS
AX-2026-041397	QYB	QYB-2601-V4429	Janoshik	2026-Q2	99.62	4.38	102.8	Buyer-sourced	0	PASS
AX-2026-041396	QYB	QYB-2601-V4429	PeptideMeter	2026-Q2	99.69	3.97	—	Buyer-sourced	0	PASS
AX-2026-041399	QYB	QYB-2601-V4429	Medutest	2026-Q2	99.79	4.10	92.5	Buyer-sourced	0	PASS

Other recent QYB records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-041471	PT-141 (Bremelanotide)	QYB-2607-L4875	Janoshik	2026-Q3	99.72	3.75	101.7	Buyer-sourced	0	PASS
AX-2026-041377	Ipamorelin	QYB-2605-H3558	Nordanalyt	2026-Q3	99.93	4.35	—	Buyer-sourced	0	PASS
AX-2026-041427	Retatrutide	QYB-2604-B4920	PeptideMeter	2026-Q3	97.93	2.45	101.7	Buyer-sourced	0	PASS
AX-2026-041428	Retatrutide	QYB-2604-B4920	Janoshik	2026-Q3	98.35	3.20	—	Laboratory-retained	0	PASS
AX-2026-041473	PT-141 (Bremelanotide)	QYB-2607-L4875	PeptideMeter	2026-Q3	99.58	3.74	94.4	Buyer-sourced	0	PASS
AX-2026-041472	PT-141 (Bremelanotide)	QYB-2607-L4875	PeptideMeter	2026-Q3	99.93	3.94	—	Buyer-sourced	0	PASS
AX-2026-041429	Retatrutide	QYB-2604-B4920	Medutest	2026-Q3	98.53	2.69	99.8	Buyer-sourced	1	MARGINAL
AX-2026-041431	Retatrutide	QYB-2604-B4920	Janoshik	2026-Q3	98.63	2.32	94.2	Buyer-sourced	0	PASS