Melanotan 2 50mg — Vial Spec, Reconstitution Math & COA

Chemical Specification and Mass Overview of Melanotan 2 (50mg Unit)

Melanotan 2 (CAS 121062-08-6) is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (α-MSH). With a molecular sequence of Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 and a nominal molecular mass of approximately 1024.2 g/mol, the molecule features a structural lactam bridge between the Asp-3 and Lys-8 residues. This cyclic constraint imparts heightened metabolic stability and enhanced receptor binding affinity compared to native linear α-MSH peptides.

A 50mg mass unit of Melanotan 2 contains 50,000 micrograms of high-purity lyophilized peptide cake. In laboratory settings, high-mass vials are designed to support extensive in vitro concentration-response curves or large-scale animal model cohorts without requiring multiple vial reconstitutions. However, managing a 50mg bulk cake demands precise volumetric calculations, strict sterile handling, and disciplined aliquot protocols to ensure that aqueous stability is maintained throughout the experimental timeline.

PX1 Format Strategy: 50mg Bulk vs. Standard Analytical Fills

In analytical chemistry, matching vial mass to experimental assay scale is critical for minimizing bio-burden and degradation. While 50mg single vials offer convenience for automated liquid-handling workstations, reconstituting a 50mg mass in a single glass container exposes a large quantity of peptide to potential hydrolytic cleavage, oxidation, and accidental microbial contamination if sampled repeatedly over weeks.

To maximize experimental repeatability and batch stability, PX1 Research prioritizes single-assay analytical packaging, specifically offering our standard Melanotan 2 10mg vial. Smaller mass formats allow research teams to reconstitute only what is required for immediate experimental protocols, preserving the remaining un-reconstituted stock under ideal desiccated, sub-zero storage conditions. Institutional laboratories requiring custom bulk fills or specialized packaging configurations can coordinate directly with our team via PX1 Wholesale services or browse our primary catalog at all peptides.

Volumetric Reconstitution Calculations for a 50mg Peptide Mass

Reconstituting a 50mg lyophilized cake requires precise volumetric preparation depending on the target stock concentration needed for microplate assays or dosing protocols. Because 50,000 micrograms is a substantial peptide mass, adding small diluent volumes yields highly concentrated stock solutions that require careful micropipetting.

The mathematical relationship between diluent volume (mL) and resulting stock concentration for a 50mg vial is calculated as follows:

1.0 mL Diluent Addition: 50mg / 1.0 mL = 50.0 mg/mL (equivalent to 50.0 µg/µL or 50,000 µg/mL). This highly concentrated stock solution is ideal for dense master plates or cold storage aliquots.

2.0 mL Diluent Addition: 50mg / 2.0 mL = 25.0 mg/mL (equivalent to 25.0 µg/µL or 25,000 µg/mL). This concentration provides a balanced viscosity for precise pipetting with standard analytical P200 micropipettes.

3.0 mL Diluent Addition: 50mg / 3.0 mL = 16.67 mg/mL (equivalent to 16.67 µg/µL or 16,667 µg/mL). Useful when working with automated liquid handlers that require moderate volumetric margins.

5.0 mL Diluent Addition: 50mg / 5.0 mL = 10.0 mg/mL (equivalent to 10.0 µg/µL or 10,000 µg/mL). A simplified metric standard frequently utilized in secondary serial dilutions.

To quickly compute custom volume-to-concentration ratios across variable vial masses, research personnel are encouraged to utilize the interactive PX1 Reconstitution Calculator.

Aliquot Management and Freeze-Thaw Degradation Protocols

When solubilizing a 50mg bulk vial of Melanotan 2, creating an immediate aliquot scheme is vital for maintaining peptide integrity. Subjecting a reconstituted liquid solution to repeated freeze-thaw cycles causes physical shear stress, peptide aggregation, and gradual loss of binding affinity at melanocortin target sites.

Following initial reconstitution with sterile bacteriostatic water (0.9% benzyl alcohol preserved) or sterile laboratory-grade phosphate-buffered saline (PBS, pH 7.4), the primary solution should be divided into single-use polypropylene microcentrifuge tubes (e.g., 50 µL to 200 µL working volumes). These individual aliquots must be rapidly frozen at -20°C or -80°C. Individual tubes are then thawed a single time immediately prior to execution of the assay protocol, ensuring that the remaining stock remains completely uncompromised.

Melanocortin Receptor Pharmacology and In Vitro Activity

Melanotan 2 acts as a non-selective, potent agonist across central and peripheral melanocortin receptors, specifically target subtypes MC1R, MC3R, MC4R, and MC5R. In preclinical literature, its primary historical benchmark involves evaluating melanogenesis and cellular skin pigmentation responses.

Preclinical studies suggest that binding to MC1R expressed on epidermal melanocyte membranes stimulates intracellular adenylate cyclase activity. This cascade increases cyclic adenosine monophosphate (cAMP) levels, upregulating tyrosinase gene expression and accelerating the synthesis of eumelanin photoprotective pigments. In vitro data indicate that Melanotan 2 demonstrates sub-nanomolar binding affinity at MC1R, making it a critical reference compound for benchmarking synthetic melanocortinergic agonists against natural α-MSH ligands. Additional findings detailing melanocortin pathway mechanisms can be reviewed across the PX1 Peptide Research Library.

Comparative Analysis: Melanocortin Class Research Peptides

When designing comparative pharmacological screens, researchers often evaluate Melanotan 2 alongside structural analogs and endogenously occurring melanocortin ligands to map receptor subtype selectivity and functional signaling potency.

Melanotan 2 is structurally distinct from other melanocortinergic research compounds due to its lactam bridge cyclization, conferring higher enzymatic resistance compared to linear peptides. When evaluating melanocortin signaling pathways, investigators frequently compare Melanotan 2 with Melanotan 1 (Afamelanotide, a linear synthetic alpha-MSH analog with selective MC1R preference), PT-141 Bremelanotide (a metabolite derivative featuring selective central MC3R/MC4R binding profiles), and endogenous peptides like ACTH 1-39 (adrenocorticotropic hormone). Understanding these structural modifications helps researchers select the appropriate compound for target-specific receptor binding assays.

Analytical Purity Verification and Lot-Matched COA Standards

Analytical precision requires strictly verified purity profiles. PX1 Research subjects every manufacturing batch to stringent third-party testing protocols conducted in independent ISO 17025 accredited laboratories located within the USA.

Purity is quantitatively verified via High-Performance Liquid Chromatography (HPLC), confirming a baseline peptide purity threshold exceeding 99.0%. Mass Spectrometry (ESI-MS) confirms exact molecular mass consistency (~1024.2 Da), verifying the absence of incomplete peptide sequences or truncated deletion fragments. Crucially, all batches undergo chromogenic Limulus Amebocyte Lysate (LAL) testing to ensure endotoxin levels remain below strictly monitored research limits (<0.01 EU/mg). Investigators can independently inspect batch-specific documentation on our Certificate of Analysis (COA) search portal.

Physical Stability, Solubilization, and Cold-Chain Storage

Lyophilized Melanotan 2 powder exhibits robust physical stability when maintained under controlled storage parameters. Unopened vials stored in a desiccated environment at -20°C maintain structural stability for up to 24 months. Storage at -80°C is recommended for multi-year repository holdings.

Once reconstituted in bacteriostatic water, liquid solutions should be kept refrigerated between 2°C and 8°C and utilized within 30 days. Reconstituted solution in plain sterile water or saline without preservatives must be used immediately or micro-aliquoted and frozen. Melanotan 2 is light-sensitive; reconstituted containers and stock aliquots must be protected from direct light exposure by utilizing amber microcentrifuge tubes or opaque storage boxes.

Selecting Optimal Vial Mass for Experimental Protocols

Determining whether a high-mass 50mg vial or a standard 10mg unit is appropriate depends on assay design, liquid handling infrastructure, and project timelines. High-throughput screening platforms utilizing continuous fluidic channels benefit from high-mass preparations. However, for standard academic and laboratory research protocols, smaller unit sizes mitigate the risk of contamination and eliminate unnecessary waste caused by solution degradation over prolonged testing cycles.