Supplied for research purposes only. These peptides are laboratory reagents intended for qualified researchers and educational institutions. Not for human use, animal use, or clinical application.
PT-141 Storage & Stability Datasheet
🖨️ NovaVitality Technical Datasheet
Document ID: NV-DS-PT141-001
Version: 1.0
Effective Date: 10 December 2025
Product: PT-141 Research Peptide (RUO)
⚠️ Controlled Substance Notice: Supplied under Human Medicines Regulations 2012, Regulation 214(2). Requires institutional Controlled Drugs (CD) Licence. Schedule 2 research substance.
1. Product Overview
| Parameter | Specification |
| INN (Proposed) | PT-141 (Bremelanotide analog) |
| CAS Status | 176200-75-4 (assigned) |
| Molecular Formula | C₅₀H₆₈N₁₄O₁₀S |
| Molecular Weight | 1025.22 g/mol (monoisotopic) |
| Sequence | Ac-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-NH₂ (cyclic, D-Phe⁴, Nle¹) |
| Receptor Profile | Selective agonist: MC4R (EC₅₀ ≈ 0.4 nM) > MC3R (EC₅₀ ≈ 2.1 nM) ≫ MC1R/MC5R |
| Form Supplied | Lyophilised Solid (white to off-white powder) |
| Purity (HPLC-UV) | ≥98% (gradient elution, C18, 220 nm) |
| Endotoxin | <1.0 EU/mg (LAL kinetic assay) |
| Residual Solvents | Meets ICH Q3C Class 3 limits |
| RUO Status | For research use only — not for human, veterinary, or therapeutic use |
| UK Control Status | Schedule 2 Research Substance — requires CD register, locked storage, and licence verification |
2. Recommended Storage Conditions
✅ Unopened (Lyophilised)
| Condition | Stability Duration | Notes |
| −20°C, desiccated, dark, in locked CD cabinet | ≥24 months | Mandatory — Schedule 2 storage requirement. Use secondary airtight container with desiccant. Amber vials with argon headspace. |
| 2–8°C (CD-locked refrigerator) | ≤6 months | For active research; log every access in CD register. |
| Room Temp (≤25°C) | ≤24 hours | For verified transit only — log receipt immediately in CD register. |
📌 PT-141 is stable lyophilised, but Trp⁶ and Asp² are oxidation/hydrolysis-sensitive. All NovaVitality vials are amber glass with argon backfill.
✅ Reconstituted (Solution)
| Solvent | Short-Term (2–8°C, CD-locked fridge) | Long-Term (−80°C, CD-locked freezer) | Notes |
| 0.1% acetic acid in 0.9% NaCl | ≤72 hours | ≤6 months (aliquoted) | Preferred — maintains cyclic integrity |
| Bacteriostatic water (0.9% BA) | ≤48 hours | ≤3 months (aliquoted) | Acceptable; benzyl alcohol does not impair MC4R activity |
| PBS (pH 7.4) | ≤24 hours | Not recommended | Risk of Asp²–Lys⁷ lactam formation |
⚠️ Critical (CD Compliance):
– All solutions must be stored in locked, access-controlled refrigerators/freezers
– Log every aliquot withdrawal in institutional CD register (date, amount, researcher, project ref, purpose)
– Limit freeze–thaw to ≤3 cycles — aggregation reduces MC4R potency
– Use low-binding tubes — cyclic peptides adsorb to standard polypropylene
3. Stability Indicators & Degradation Risks
| Risk Factor | Effect on PT-141 | Detection Method |
| Light exposure (UV/visible) | Trp⁶ oxidation → kynurenine (+4 Da) | LC-MS: +4 Da peak; ↓cAMP in HEK293-MC4R |
| Moisture/heat | Asp²–Lys⁷ lactam formation | HPLC: new peak at ~8.2 min; altered MC4R:MC3R bias |
| Alkaline pH (>7.5) | Arg⁵ deimination → citrulline | MS/MS: loss of guanidino group; ↓ receptor binding |
| Repeated freeze–thaw | Irreversible dimerisation (Trp crosslinks) | SEC-HPLC: high-MW peaks; ↓ solubility |
| Reducing agents | Disulfide scrambling (none present) | Not applicable — no Cys |
🔬 Tip: Validate bioactivity pre-assay: run MC4R cAMP EC₅₀ — potency loss >2-fold indicates degradation.
4. Reconstitution Protocol (Best Practice + CD Compliance)
- Log withdrawal in CD register (vial lot, amount, researcher, date, project ref, purpose: “MC4R pharmacology research”).
- Equilibrate vial to room temp (10 min) inside CD cabinet.
- Centrifuge briefly (3 sec) to collect powder.
- Add 0.1% acetic acid/saline slowly down vial wall (e.g., 1 mL for 10 mg → 10 mg/mL).
- Gently swirl — do not vortex or sonicate.
- Filter through 0.22 µm PVDF (low-protein-binding).
- Aliquot in pre-labelled, CD-compliant tubes, log volumes, flash-freeze at −80°C (CD-locked).
5. Analytical Verification (Post-Storage)
| Test | Acceptance Criteria | When to Run |
| HPLC Purity | ≥95% main peak | After >3 months storage, or pre-critical assay |
| LC-MS Identity | Observed MW 1025.2 ±1.0 Da | Annually, or after suspected degradation |
| Endotoxin | <5 EU/mL in solution | Before in vivo studies |
| Bioactivity (Required) | EC₅₀ ≤ 0.6 nM at hMC4R (cAMP, HEK293) | For all publication or longitudinal studies |
6. References & Compliance
- Wessells H et al. Int J Impot Res. 2000;12(Suppl 4):S90–S94. DOI: 10.1038/sj.ijir.3900541
- UK Human Medicines Regulations 2012 (SI 2012/1916), Regulation 214(2)
- MHRA Guidance on Supply of Unlicensed Medicinal Products for Research (Dec 2024)
- Home Office Guidance on Controlled Drugs in Research (2023)
- ICH Q1A(R2): Stability Testing
7. Support & Documentation
📧 CD & Technical queries: [email protected]
🔒 This datasheet is for informational purposes only. NovaVitality supplies under Regulation 214(2) for research. Researchers must hold a valid CD Licence and comply with the Misuse of Drugs Regulations 2001. NovaVitality disclaims all liability for non-compliant use.
