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An authoritative analysis of Melanotan II (MT-2) cyclic lactam synthesis, stereochemical integrity, and enterprise procurement considerations for multinational pharmaceutical and biotechnology buyers.
Melanotan II (CAS No. 121062-08-6), designated systematically as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, is a synthetic cyclic heptapeptide analog of the endogenous physiological alpha-melanocyte-stimulating hormone ($\alpha$-MSH). Engineered specifically for enhanced metabolic stability and sub-nanomolar affinity across the melanocortin receptor family (MC1R, MC3R, MC4R, and MC5R), Mt 2 incorporates two decisive chemical modifications that distinguish it from linear pro-opiomelanocortin (POMC) cleavage derivatives: the substitution of standard Norleucine (Nle) at the N-terminus and the intramolecular cyclization between the side chains of Aspartic Acid ($\text{Asp}^2$) and Lysine ($\text{Lys}^7$).
From an industrial manufacturing perspective, solid-phase peptide synthesis (SPPS) of Mt 2 presents acute stereochemical and conformational hurdles. The primary engineering bottleneck resides in the selective, orthogonal deprotection and on-resin or in-solution lactam ring closure. The presence of the critical D-Phenylalanine ($\text{D-Phe}^4$) chiral residue is indispensable for biological activity; however, unoptimized coupling conditions using standard carbodiimide activation chemistry routinely induce micro-racemization into the inactive L-Phe diastereomer. Our facility eliminates this risk through low-temperature phosphonium/uronium-mediated activation (HATU/HOAt/Oxyma Pure) under strictly non-basic running buffers, driving stereochemical retention beyond 99.85%.
| Test Parameter | Standard Specifications (Analytical Grade) | Enterprise Commercial Grade (Thinheal Standard) | Analytical Methodology |
|---|---|---|---|
| Primary Sequence | Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 | Confirmed sequence match; 100% fidelity | HR-MS / Amino Acid Analysis (AAA) |
| Molecular Formula / Weight | C50H69N15O9 / 1024.18 g/mol | Monoisotopic Mass: 1023.54 Da (±0.5 Da match) | ESI-MS / MALDI-TOF |
| Chromatographic Purity | ≥ 98.0% by RP-HPLC | ≥ 99.20% (Single largest impurity <0.5%) | RP-HPLC (C18 Column, 220nm detection) |
| Counter-Ion Content | Trifluoroacetate (TFA) ≤ 12% | Acetate Form (≤ 8.0%) or Acetate-to-Base conversion | Ion Chromatography (IC) / 19F-NMR |
| Net Peptide Content | ≥ 75.0% | ≥ 82.5% to 88.0% | Nitrogen Determination (Kjeldahl) / UV |
| Bacterial Endotoxins | < 50 EU/mg | < 5.0 EU/mg (Ultra-pure formulation grade) | Kinetic Turbidimetric LAL Assay |
| Residual Solvents | Meets USP <467> / ICH Q3C limits | ACN < 410 ppm, DMF < 880 ppm, DCM < 600 ppm | Headspace Gas Chromatography (GC-MS) |
The worldwide peptide therapeutics and biochemical API marketplace is experiencing profound transformation. Propelled by advances in metabolic and dermatological clinical pipelines, demand for melanocortin receptor ligands has expanded at an annualized CAGR exceeding 14.8%. However, international purchasers—spanning contract manufacturing organizations (CMOs), analytical laboratories, and formulations developers—face systemic hurdles across traditional supply channels.
Supply Chain Fragility & Raw Material Volatility: The synthesis of Mt 2 requires critical chiral synthons, primarily protected Fmoc-D-Phe-OH and specialized side-chain-cleavable orthogonal derivatives such as Fmoc-Asp(OAll)-OH and Fmoc-Lys(Alloc)-OH. Geopolitical friction and environmental auditing have repeatedly destabilized upstream chemical refineries, causing price volatility and lead-time delays of up to 26 weeks. Through Hangzhou Thinheal's vertically integrated procurement architecture, our direct synthesis of key non-canonical amino acids buffers institutional clients from price spikes and supply disruptions.
Quality Heterogeneity in Open-Market Quotations: Sourcing managers frequently encounter quote discrepancies for Mt 2 ranging from $15/gram to $150/gram. This spread typically obscures deep technical compromises: inexpensive wholesale lots frequently suffer from high levels of truncated deletion sequences (e.g., des-Arg or des-Trp artifacts), incomplete cyclization products (open-chain dicarboxylic intermediaries), and toxic organotin or palladium catalysts remaining from catalytic allyl deprotection steps.
Proprietary microwave-assisted on-resin side-chain cyclization yields >92% intramolecular conversion without oligomeric poly-condensation artifacts.
Comprehensive replacement of residual cytotoxic Trifluoroacetic Acid (TFA) salts with pharmaceutically acceptable Acetate or Hydrochloride counter-ions.
Comprehensive Module 3 Chemistry, Manufacturing, and Controls (CMC) technical support including validation of analytical procedures (ICH Q2(R1)).
Transparent, volume-tiered industrial quotes engineered for institutional procurement directors, academic consortia, and commercial formulation operations.
| Order Quantity Tier | Purity Classification | Counter-Ion Type | Packaging Configuration | Standard Lead Time | Contract Pricing Guidance |
|---|---|---|---|---|---|
| Pilot / R&D (10g – 50g) | ≥ 98.0% HPLC | Trifluoroacetate (TFA) | Amber Serum Vials (1g, 5g, 10g) | Immediate Dispatch (Stock) | Tier 1 Spot Quote |
| Scale-Up Pilot (100g – 500g) | ≥ 98.5% HPLC | TFA or Acetate (on request) | HDPE Borosilicate Bottles / Vacuum Pack | 1 – 2 Weeks | Volume Tier 2 (-18%) |
| Pre-Clinical / Batch (1kg – 5kg) | ≥ 99.0% HPLC | Standard Acetate Salt | Double-welded antistatic bags in Alu-pouch | 2 – 3 Weeks | Commercial Tier 3 (-35%) |
| Commercial Multi-Kg (> 10kg) | ≥ 99.2% (Ultra-Clean) | Purified Acetate / Base | Custom bulk drum with secondary nitrogen seal | Scheduled Campaign / Standing Order | Dedicated CDMO Contract |
When reviewing formal proposals from our peptide API desk, procurement departments should understand the precise process chemistry nodes that influence final unit pricing:
1. Net Peptide Content (NPC) vs. Gross Weight: A quote of $1,000 for 100g of lyophilized powder with an NPC of 70% yields only 70g of active Mt 2 moiety. Thinheal guarantees high net peptide content (typically 84–88%), significantly lowering the effective cost per active gram compared to industry averages.
2. Counter-Ion Exchange Processing: Trifluoroacetic acid is universally used during the cleavage cocktail phase ($\text{TFA} / \text{TIS} / \text{EDT} / \text{H}_2\text{O}$). Converting this salt to an acetate form requires multi-stage ion-exchange chromatography or repeated counter-ion displacement precipitation. This adds approximately 10–15% to production costs but is critical for non-toxic biological administration.
3. Preparative Chromatography Yields: High-performance preparative axial compression HPLC columns (using 10µm–15µm C18 stationary phases) demand significant quantities of high-purity acetonitrile and purified water. Achieving ≥99.2% purity requires tighter fraction cutoffs, yielding higher purity at the expense of crude material recovery.
Reliable supply continuity backed by international trade compliance, temperature-monitored cold-chain distribution, and ongoing green synthesis innovation.
Dedicated commercial units operate across North America, the European Union, Russia/CIS, and Southeast Asia, offering rapid turnaround in local time zones.
Peptide APIs undergo calibrated secondary container sealing under dry nitrogen and ship with certified dry-ice or thermal gel loggers.
Pioneering the shift away from hazardous DMF/DCM solvents to eco-friendly greener alternatives like Cyrene, NBP, and 2-MeTHF.
Detailed technical answers addressing core evaluation criteria for custom Melanotan II (Mt 2) peptide synthesis, compliance, and ordering protocols.
Browse our extended multi-ton production catalog, covering triple-receptor incretins, tissue regenerative fragments, and high-purity cosmetic bio-actives.
Submit target specifications, batch volumes, desired counter-ion balances (TFA/Acetate), and delivery timelines directly to our peptide CDMO team in Hangzhou. Receive a comprehensive technical proposal within 24 hours.
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