Purity at 99.80 % and water at 4.07 %: the two numbers are independent and both are needed. Excellent chromatography on a wet cake still yields less peptide per vial than the label implies.
AX-2024-004961
PT-141 (Bremelanotide) · 10 mg declared · Xi'an Mokemei Biotechnology Co., Ltd. · lot MKM-2404-E3617
PASSVERIFIED
- Report ID
- AX-2024-004961
- Compound
- PT-141 (Bremelanotide)
- Compound class
- Melanocortin-receptor peptides
- Supplier
- MKM — Xi'an Mokemei Biotechnology Co., Ltd.
- Batch / lot
- MKM-2404-E3617
- Declared label claim
- 10mg
- Laboratory
- Janoshik Analytical
- Assay date
- 21 Aug 2024
- Submitted
- 23 Aug 2024
- Quarter
- 2024-Q3
- Submitter
- c.okonkwo
- Sample provenance
- Buyer-sourced
Section 1
Results
Measured against the index acceptance specification for the melanocortin-receptor 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 | 99.80 | % area | ≥ 98.5 | PASS |
| Total impurities | RP-HPLC, sum of reported peaks | 0.20 | % area | ≤ 1.5 | PASS |
| Largest single impurity | RP-HPLC — linear precursor (+18 Da) | 0.13 | % area | ≤ 1.00 | PASS |
| Identity — theoretical monoisotopic mass | calculated from molecular formula | 1024.5242 | Da | — | NOT TESTED |
| Identity — observed monoisotopic mass | LC-MS, high resolution (ESI-TOF/QTOF) | 1024.5294 | Da | — | NOT TESTED |
| Mass accuracy | observed vs theoretical | +5.1 | ppm | ± 15 | PASS |
| Total peptide content | by difference from the gravimetric mass balance | 90.59 | %w/w | — | NOT TESTED |
| Target-compound content | total peptide content × purity | 90.41 | %w/w | — | NOT TESTED |
| Gross fill (as weighed) | five-place balance, under nitrogen | 11.23 | mg | 10 mg declared | NOT TESTED |
| Recovered target peptide | gross fill × target content | 10.153 | mg | 10 mg claim | NOT TESTED |
| Recovery against label claim | recovered ÷ claim | 101.5 | % | 90.0 – 110.0 | PASS |
| Water content | Karl Fischer, coulometric, duplicate | 4.07 | % | ≤ 8.0 | PASS |
| Counter-ion (acetate) | anion-exchange ion chromatography | 5.06 | % | ≤ 10.0 | PASS |
| Residual solvent + inorganic residue | estimated — see /methods/residual-solvents-q3c/ | 0.28 | % | — | NOT TESTED |
| Endotoxin | kinetic chromogenic LAL | 0.23 | 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 with a single visible fibre | — | clear, no visible particulates | FAIL |
| pH (reconstituted, 1 mg/mL) | potentiometric, two-point calibration | 5.90 | — | 2.5 – 8.0 | PASS |
| Retention time (observed) | RP-HPLC, 30 min gradient | 9.71 | min | 9.52 ± 0.25 (normalised) | PASS |
| Peak asymmetry (10 % height) | Ph. Eur. 2.2.46 | 0.92 | — | 0.80 – 1.50 | PASS |
| Plate count, main peak | N = 5.54 (t/w½)² | 62,754 | — | ≥ 20,000 | PASS |
| Resolution to nearest impurity | vs melanotan II (C-terminal amide, −1 Da) | 2.01 | — | 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.
| # | Peak | RT | Area (µV·s) | % area | Δ mass (Da) |
|---|---|---|---|---|---|
| 1 | PT-141 (Bremelanotide) — main peak | 9.71 | 4,850,589 | 99.80 | — |
| 2 | linear precursor (+18 Da) | 9.01 | 6,318 | 0.13 | +18.011 |
| 3 | melanotan II (C-terminal amide, −1 Da) | 10.03 | 2,430 | 0.05 | -0.984 |
| 4 | oxidised Trp (+16 Da) | 9.37 | 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 1024.5242 Da, computed from C50H68N14O10. All ppm figures on this site are against monoisotopic values — see why that matters.
| Charge | Theoretical m/z | Observed m/z | Δ m/z | Rel. abundance (%) |
|---|---|---|---|---|
| 3+ | 342.5153 | 342.5171 | 0.0018 | 7.8 |
| 2+ | 513.2694 | 513.2720 | 0.0026 | 53.2 |
| 1+ | 1025.5315 | 1025.5367 | 0.0052 | 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 | 4.07 |
| Counter-ion (acetate) | ion chromatography | 5.06 |
| Residual solvent + inorganic residue | estimated | 0.28 |
| Total peptide content | by difference | 90.59 |
| 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) | 99.90 | 99.80 | divergence 0.00 pp vs batch median |
| Total impurities (% area) | not stated | 0.20 | |
| Largest single impurity (% area) | not stated | 0.13 | |
| Water (%) | 3.0 | 4.07 | |
| Counter-ion (%) | not stated | 5.06 | |
| Peptide content (%w/w) | not stated | 90.59 | |
| Endotoxin (EU/mg) | not stated | 0.23 | |
| 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 (2–8 °C, 22 d) → laboratory (courier, ambient, 6 d) → assay.
- Assay date
- 21 Aug 2024
- Submitted to the index
- 23 Aug 2024
- Laboratory
- Janoshik Analytical, Ostrava, Czechia
- Method basis
- 30 min gradient · high-resolution MS
- Verification status
- VERIFIED
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.
Nothing here rules out a positional isomer with the same formula. Mass cannot; only chromatography can, and the gradient length on this record is the relevant fact for that.
The certificate that arrives with a retail order is the certificate an ordinary buyer gets. Assessing it is assessing the real documentation practice rather than the sample-request one.
Section 7
Related records
Same batch — lot MKM-2404-E3617 n=5
| Report | Lot | Lab | Quarter | Purity % | Water % | Recovery % | Provenance | Flags | Result |
|---|---|---|---|---|---|---|---|---|---|
| AX-2024-004959 | MKM-2404-E3617 | Kestrel | 2024-Q3 | 99.93 | 4.07 | — | Buyer-sourced | 1 | FAIL |
| AX-2024-004960 | MKM-2404-E3617 | VendorInvestigate | 2024-Q3 | 99.78 | 4.33 | — | Buyer-sourced | 0 | PASS |
| AX-2024-004962 | MKM-2404-E3617 | Janoshik | 2024-Q3 | 99.90 | 3.80 | — | Buyer-sourced | 0 | PASS |
| AX-2024-004963 | MKM-2404-E3617 | Janoshik | 2024-Q3 | 99.93 | 4.73 | — | Laboratory-retained | 0 | PASS |
Cross-sections
| Report | Supplier | Lot | Lab | Quarter | Purity % | Water % | Recovery % | Provenance | Flags | Result |
|---|---|---|---|---|---|---|---|---|---|---|
| AX-2026-041471 | QYB | QYB-2607-L4875 | Janoshik | 2026-Q3 | 99.72 | 3.75 | 101.7 | Buyer-sourced | 0 | PASS |
| AX-2026-041473 | QYB | QYB-2607-L4875 | PeptideMeter | 2026-Q3 | 99.58 | 3.74 | 94.4 | Buyer-sourced | 0 | PASS |
| AX-2026-041472 | QYB | QYB-2607-L4875 | PeptideMeter | 2026-Q3 | 99.93 | 3.94 | — | Buyer-sourced | 0 | PASS |
| AX-2026-041474 | QYB | QYB-2607-L4875 | VendorInvestigate | 2026-Q3 | 99.16 | 3.78 | 95.6 | Buyer-sourced | 0 | PASS |
| AX-2026-041470 | QYB | QYB-2607-L4875 | Janoshik | 2026-Q3 | 99.77 | 4.10 | — | Buyer-sourced | 0 | PASS |
| AX-2026-042139 | JEEP | JEEP-2601-K8195 | VendorInvestigate | 2026-Q2 | 98.32 | 4.29 | 99.4 | Buyer-sourced | 1 | FAIL |
| AX-2026-041964 | AMB | AMB-2601-M5602 | Janoshik | 2026-Q2 | 99.93 | 3.20 | — | Buyer-sourced | 0 | PASS |
| AX-2026-041664 | FGP | FGP-2602-Y8741 | Janoshik | 2026-Q2 | 99.90 | 4.48 | 106.5 | Buyer-sourced | 0 | PASS |
| Report | Compound | Lot | Lab | Quarter | Purity % | Water % | Recovery % | Provenance | Flags | Result |
|---|---|---|---|---|---|---|---|---|---|---|
| AX-2026-042942 | CJC-1295 (no DAC) | MKM-2603-V3346 | Janoshik | 2026-Q3 | 99.52 | 3.43 | — | Supplier-supplied | 0 | PASS |
| AX-2026-043019 | Adipotide | MKM-2606-K5012 | Janoshik | 2026-Q3 | 97.61 | 5.77 | 105.1 | Buyer-sourced | 0 | PASS |
| AX-2026-042939 | CJC-1295 (no DAC) | MKM-2603-V3346 | PeptideMeter | 2026-Q3 | 99.44 | 3.39 | — | Buyer-sourced | 0 | PASS |
| AX-2026-043020 | Adipotide | MKM-2606-K5012 | Medutest | 2026-Q3 | 97.73 | 5.74 | — | Buyer-sourced | 0 | PASS |
| AX-2026-043022 | Adipotide | MKM-2606-K5012 | Kestrel | 2026-Q3 | 97.69 | 6.33 | 106.9 | Buyer-sourced | 0 | PASS |
| AX-2026-043023 | Adipotide | MKM-2606-K5012 | Medutest | 2026-Q3 | 97.48 | 5.56 | 103.7 | Supplier-supplied | 0 | PASS |
| AX-2026-042945 | CJC-1295 (no DAC) | MKM-2603-V3346 | PeptideMeter | 2026-Q3 | 99.39 | 3.54 | — | Laboratory-retained | 0 | PASS |
| AX-2026-042938 | CJC-1295 (no DAC) | MKM-2603-V3346 | Nordanalyt | 2026-Q3 | 99.47 | 3.67 | 95.0 | Buyer-sourced | 0 | PASS |