Melanotan 2 15mg — Vial Spec, Reconstitution Math & COA

Melanotan 2 15mg Vial Specifications & Availability Context

A 15mg vial of Melanotan 2 (MT-2) contains 15 milligrams of highly purified, lyophilized synthetic cyclic heptapeptide cake formulated alongside a stabilizing bulking agent such as mannitol. Principal investigators and laboratory managers typically select 15mg unit sizes for large-scale in vitro assays, high-density cell line exposures, or non-human animal research series where high working concentrations are required over extended periods. Utilizing a single larger mass vial helps maintain consistent target concentrations without introducing variable batch metrics across multiple small-volume reconstitutions.

It is important to note that while some external catalog vendors distribute a 15mg presentation, PX1 Research standardizes its primary melanocortin inventory around the widely validated Melanotan 2 10mg vial. For laboratories requiring larger total peptide yields, multiple 10mg units or bulk custom fills can be ordered through our wholesale catalog to ensure identical lot-matched purity and minimal container-closure decay. All peptides supplied by PX1 Research—regardless of mass configuration—are restricted strictly to in vitro and preclinical laboratory research.

Molecular Structure & Melanocortin Receptor Binding Profile

Melanotan 2 is a synthetic lactam-bridged cyclic analog of alpha-melanocyte-stimulating hormone (α-MSH). Chemically designated as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, it features a molecular formula of C50H69N15O9 and a molecular weight of approximately 1024.2 g/mol. The lactam ring conformation confers significant enzymatic resistance against aminopeptidases, endopeptidases, and central metabolic clearance mechanisms, yielding a dramatically prolonged half-life in physiological buffer solutions compared to native linear α-MSH.

In preclinical model systems, Melanotan 2 acts as a non-selective, potent agonist across multiple central and peripheral melanocortin receptor subtypes. In vitro receptor binding assays demonstrate high binding affinities for MC1R, MC3R, MC4R, and MC5R. The primary pharmacological focus of research involving MT-2 centers on its melanocortin activity related to skin pigmentation responses mediated through MC1R signaling in cutaneous melanocytes. Additionally, binding at central MC4R and MC3R sites is investigated in rodent models to study central energy homeostasis, feeding behavior, and neuroendocrine signaling pathways.

Reconstitution Mathematics for 15mg Lyophilized Vials

Accurate reconstitution mathematics is critical for maintaining exact dosage parameters during liquid handling in automated pipetting platforms or manual assay preparations. When calculating final target concentrations for a 15mg lyophilized vial, the volumetric displacement of the lyophilized cake is considered negligible, meaning the added diluent volume dictates the final concentration (mg/mL or µg/µL).

The fundamental concentration formula is: Concentration (mg/mL) = Total Peptide Mass (mg) / Volumetric Solvent Added (mL). To determine precise microgram per microliter metrics or convert units for precise pipetting, researchers should reference our interactive reconstitution calculator. Below are standard reference concentrations calculated for a 15mg vial using common laboratory reconstitution volumes:

1. Reconstitution with 1.0 mL Solvent: Adding 1.0 mL of Bacteriostatic Water (0.9% benzyl alcohol) or Sterile Phosphate-Buffered Saline (PBS) yields a stock concentration of 15.0 mg/mL (15.0 µg/µL). This concentrated formulation is ideal for minimal-volume micro-dosing in automated cell microplates.

2. Reconstitution with 2.0 mL Solvent: Adding 2.0 mL of reconstituting diluent results in a working stock concentration of 7.5 mg/mL (7.5 µg/µL). This concentration facilitates highly accurate volumetric measurement using standard laboratory micropipettes.

3. Reconstitution with 3.0 mL Solvent: Diluting a 15mg cake with 3.0 mL yields a final solution concentration of 5.0 mg/mL (5.0 µg/µL). This lower density simplifies serial dilutions across multi-well cellular assay series.

Laboratory Solvent Selection & Aliquoting Protocol

Choosing the appropriate solvent depends directly on the intended downstream experimental assay and required shelf-life post-reconstitution. For multi-use laboratory stock solutions stored at 2°C to 8°C over 14 to 28 days, Bacteriostatic Water containing 0.9% benzyl alcohol is recommended to inhibit microbial growth. When preparing solutions for acute cell culture or sensitive in vitro assays where benzyl alcohol could induce cellular toxicity, sterile, pyrogen-free normal saline (0.9% NaCl) or pH-balanced PBS (pH 7.4) should be utilized.

To prevent repeated freeze-thaw cycles—which cause peptide degradation through mechanical shear forces and localized concentration spikes—a rigorous aliquoting workflow must be implemented immediately post-reconstitution. Once the 15mg cake is fully dissolved, split the stock solution into single-use microcentrifuge tubes (e.g., 50 µL to 200 µL per tube) made of low-protein-binding polypropylene. Flash-freeze these working aliquots in liquid nitrogen or an ethanol/dry-ice bath prior to transfer into long-term cryo-storage.

Thermal Stability & Long-Term Cryo-Storage Guidelines

In its native, lyophilized powder state, Melanotan 2 exhibits excellent structural stability. Lyophilized 15mg vials stored at -20°C maintain chemical integrity and physical stability for up to 24 months, provided the vial seal remains intact and protected from direct ultraviolet light. Unopened vials stored at controlled ambient room temperatures (20°C to 25°C) remain stable for short-term transit periods of up to 30 days without measurable loss of peptide purity.

Following reconstitution, the cyclic peptide matrix becomes susceptible to liquid-phase hydrolysis and aggregation. Reconstituted aqueous solutions remain stable at 2°C to 8°C for up to 30 days if prepared with bacteriostatic solvent. Frozen liquid aliquots held at -80°C demonstrate functional stability for up to 12 months. Laboratories must avoid non-frost-free freezers, as ambient temperature fluctuations during automatic defrost cycles lead to crystalline formation and peptide bond breakage.

Quality Assurance: HPLC, Mass Spectrometry & Endotoxin Limits

To ensure reproducible experimental outcomes, every peptide lot produced for PX1 Research undergoes stringent multi-stage analytical validation at an independent ISO 17025 accredited laboratory. Researchers can independently verify the identity, purity, and safety profile of their lot by reviewing our publicly accessible Certificate of Analysis (COA) directory.

Purity assessment is performed using High-Performance Liquid Chromatography (HPLC) coupled with ultraviolet detection. PX1 Research mandates a minimum purity threshold of ≥98.0% across all peptide lots. Molecular weight verification is established using Electrospray Ionization Mass Spectrometry (ESI-MS), confirming the exact monoisotopic mass of 1024.2 Da without unexpected adducts or manufacturing impurities. Furthermore, because sub-visible bacterial contaminants disrupt cellular assays, every lot undergoes Chromogenic LAL Endotoxin Testing to ensure levels remain under strictly controlled limits (<0.01 EU/µg).

Selecting Vial Mass: 10mg vs 15mg Laboratory Considerations

Determining whether a 10mg or 15mg unit size is superior depends primarily on the experimental volume, assay frequency, and waste minimization strategy of the research facility. High-throughput screening projects, continuous flow experiments, and extensive rodent studies benefit from 15mg vials due to reduced reconstitution overhead and reduced inter-vial variation.

Conversely, smaller investigative studies, preliminary pilot assays, or occasional cell culture exposures are often better served by standard 10mg configurations. Because reconstituted peptide solutions face progressive degradation over extended periods, opening a smaller total mass minimizes the volume of active compound exposed to ambient light, room temperature, and liquid storage degradation. Facilities seeking to compare complete peptide specifications across various unit masses can review the complete catalog via our all peptides hub.

Comparative Analysis: Melanocortin Receptor Agonists

When designing melanocortin receptor activation studies, principal investigators often compare Melanotan 2 against structurally related research analogs within the melanocortin peptide class. The most notable counterparts in preclinical literature are Bremelanotide PT-141 and Afamelanotide MT-1. Both compounds share underlying structural homology with α-MSH but demonstrate distinct receptor selectivity profiles and physiological binding dynamics.

Afamelanotide (Melanotan I) is a linear peptide agonist exhibiting high selectivity for the MC1R subtype, making it a primary benchmark in melanogenesis and photoprotection studies. Bremelanotide (PT-141), a active metabolite structure derived from Melanotan 2, lacks the C-terminal modifications of MT-2 and demonstrates selective binding to central MC3R and MC4R targets. Comparative binding studies assist research teams in isolating peripheral melanogenic responses from central neuroendocrine pathway activation.

Experimental Handling & In Vitro Assay Protocols

When handling Melanotan 2 in the laboratory, strict aseptic technique must be maintained inside a certified Class II Laminar Flow Biosafety Cabinet. The outer aluminum flip-cap should be removed, and the butyl rubber stopper swabbed thoroughly with 70% isopropyl alcohol prior to needle insertion. Sterile single-use syringes should be used to introduce diluent down the glass vial wall, allowing gentle dissolution without aggressive shaking or vortexing.

In cell culture models, working stock solutions are typically introduced into serum-free media formulations to measure tyrosinase activity, intracellular cyclic AMP (cAMP) accumulation, or melanin production kinetics in B16-F10 melanoma cell lines or human primary melanocytes. For broader compound documentation and peer-reviewed methodology references, researchers can explore our dedicated peptide research library.