PT-141 5mg — Vial Spec, Reconstitution Math & COA
A 5mg vial of PT-141 (Bremelanotide) delivers a precise unit mass of a synthetic cyclic heptapeptide melanocortin receptor agonist engineered for in vitro and preclinical research applications. Designed for laboratories studying central neurochemical signaling pathways, this fill mass provides an ideal balance between reagent economy and multi-assay usability. Researchers seeking analytical verification, lot-specific purity data, or alternative unit masses can review our full catalog of [all-peptides](/all-peptides) for certified research reagents.
Quick answer
A 5mg vial of PT-141 (Bremelanotide) delivers a precise unit mass of a synthetic cyclic heptapeptide melanocortin receptor agonist engineered for in vitro and preclinical research applications. Designed for laboratories studying central neurochemical signaling pathways, this fill mass provides an ideal balance between reagent economy and multi-assay usability. Researchers seeking analytical verification, lot-specific purity data, or alternative unit masses can review our full catalog of [all-peptides](/all-peptides) for certified research reagents.
Key takeaways
- The 5mg vial of [PT-141](/research-peptides/pt-141) contains lyophilized Bremelanotide acetate, a synthetic peptide analogue of alpha-melanocyte-stimulating hormone (α-MSH).
- [PT-141](/research-peptides/pt-141) functions primarily as a high-affinity non-selective agonist across central melanocortin receptors, displaying potent activity at MC3R and MC4R subtype receptors, with secondary interaction at MC1R.
- Accurate volumetric reconstitution is essential to achieving consistent target concentrations for laboratory assays.
- Repeated freeze-thaw cycles accelerate peptide degradation via peptide backbone cleavage and aggregation.
Overview of PT-141 5mg Vial Specifications and Format Availability
The 5mg vial of PT-141 contains lyophilized Bremelanotide acetate, a synthetic peptide analogue of alpha-melanocyte-stimulating hormone (α-MSH). In laboratory settings, this exact 5mg mass format is selected by research teams conducting medium-throughput receptor binding assays, cellular signaling measurements, or targeted animal model studies where fresh reconstitution of smaller batches is preferred to prevent multiple freeze-thaw cycles.
When evaluating inventory specifications at PX1 Research, laboratory managers should note that while standard product lines frequently utilize the popular PT-141 10mg vial format for higher volume research initiatives, 5mg configurations represent a strategic unit mass for targeted pilot studies. Regardless of total mass per vial, every unit is freeze-dried under strict sterile parameters with inert mannitol bulking agents to ensure rapid dissolution, maximal cake integrity, and long-term peptide stability.
Melanocortin Agonism: Mechanism of Action and Receptor Affinity
PT-141 functions primarily as a high-affinity non-selective agonist across central melanocortin receptors, displaying potent activity at MC3R and MC4R subtype receptors, with secondary interaction at MC1R. Unlike traditional vasoactive agents that alter peripheral vascular dynamics directly through nitric oxide pathways, preclinical evidence indicates that PT-141 acts within the central nervous system—specifically targeted to the hypothalamus—to modulate downstream neuroendocrine and behavioral responses.
In animal study models, activation of central MC4R pathways by PT-141 triggers neuronal signaling cascades in the medial preoptic area (mPOA) and ventral tegmental area (VTA). These neurochemical shifts stimulate dopamine release, modulating central drive and investigational metrics linked to sexual-health pathways. In vitro assays demonstrate that binding of PT-141 to melanocortin receptors stimulates intracellular adenylate cyclase activity, leading to elevated cyclic adenosine monophosphate (cAMP) accumulation without requiring direct adrenergic or cholinergic receptor involvement.
PT-141 5mg Reconstitution Math and Concentration Calculations
Accurate volumetric reconstitution is essential to achieving consistent target concentrations for laboratory assays. Reconstituting a 5mg (5,000 µg) lyophilized vial requires measuring the diluent volume precisely using sterile laboratory technique. Researchers can model custom volumetric scenarios using our online reconstitution-calculator, or refer to standard volumetric standardizations outlined below.
When adding 1.0 mL of sterile diluent (such as 0.9% bacteriostatic water or sterile normal saline) to a 5mg vial, the final concentration yields exactly 5.0 mg/mL, or 5,000 µg/mL (equivalent to 50 µg per 10 µL micro-aliquot). If the protocol calls for a 2.0 mL dilution volume, the working concentration shifts to 2.5 mg/mL, or 2,500 µg/mL (25 µg per 10 µL). Introducing 3.0 mL of diluent dilutes the mixture to approximately 1.67 mg/mL, or 1,666.7 µg/mL (16.67 µg per 10 µL). Maintaining detailed concentration logs ensures operational precision across serial dilution experiments.
Aliquot Planning and Micro-Volume Assay Handling
Repeated freeze-thaw cycles accelerate peptide degradation via peptide backbone cleavage and aggregation. For experimental protocols extending across days or weeks, aliquot planning must be executed immediately post-reconstitution. Once the 5mg lyophilized cake is fully solubilized, the solution should be drawn into sterile, low-protein-binding polypropylene microcentrifuge tubes in pre-calculated working volumes.
For example, a 5mg vial reconstituted in 2.0 mL of diluent can be divided into twenty 100 µL aliquots, each containing 250 µg of PT-141. Single-use aliquots intended for future assay runs should be immediately frozen at -20°C or -80°C. Working aliquots designated for immediate use within 24 to 48 hours may be held at 2°C to 8°C. This systematic handling routine protects structural integrity and prevents concentration drift caused by solvent evaporation or physical degradation.
Comparative Analysis: PT-141 vs. Related Melanocortin Agonists
To properly position PT-141 within a broader neurochemical research framework, investigators frequently compare its selectivity and structural modifications against other synthetic melanocortin agonists. While PT-141 is a metabolite derivative of Melanotan II, key structural alterations fundamentally change its functional receptor profile and target application scope.
Compared to melanotan-2, which exhibits robust affinity for MC1R leading to significant melanogenesis activation alongside MC3R/MC4R signaling, PT-141 demonstrates relative functional selectivity toward central MC3R/MC4R signaling pathways. Furthermore, native endogenous peptides like alpha-msh possess exceptionally short biological half-lives due to rapid enzymatic degradation by circulating endopeptidases. In contrast, the cyclic structure of PT-141 confers enhanced enzymatic stability, making it far superior for extended in vitro binding assays and in vivo pharmacokinetic profiling.
Storage Parameters for Lyophilized and Reconstituted Peptides
Maintaining chemical stability requires strict environmental control during both short-term storage and long-term archivation. Lyophilized PT-141 5mg vials must be stored in temperature-monitored freezers maintained at -20°C (-4°F) or below. Protected from light exposure and humidity in sealed amber containers or boxed storage racks, un-reconstituted vials maintain analytical purity for up to 24 months from the date of manufacture.
Following solvent addition, reconstituted solutions are substantially more sensitive to thermal and physical degradation. Reconstituted vials or aliquots stored at standard refrigeration temperatures (2°C to 8°C) should be utilized within 14 to 21 days when preserved with bacteriostatic diluents. Avoid store locations near refrigerator doors where temperature fluctuations occur, and never subject reconstituted liquid solutions to ultrasonic agitation or violent vortexing, which can disrupt secondary structural conformation.
Quality Assurance: Mass Spectrometry, HPLC, and Lot-Matched COAs
High-purity research compounds are vital to producing reliable, reproducible scientific data. Every lot of PT-141 distributed by PX1 Research undergoes rigorous third-party analytical testing prior to release. Quality verification relies on dual-stage analytical techniques: High-Performance Liquid Chromatography (HPLC) to establish chromatographic purity, and Electrospray Ionization Mass Spectrometry (ESI-MS) to verify exact molecular mass and sequence identity.
Researchers can review and download comprehensive lot-specific documentation directly through our centralized coa repository. Each Certificate of Analysis details overall purity percentages (exceeding our minimum threshold of 99%), analytical baseline chromatograms, net peptide content, and mass spectral confirmation. This transparent chain of custody ensures that experimental variations stem exclusively from biological variables, rather than chemical impurity.
Selecting the Optimal Vial Mass for Laboratory Scale
Choosing between a 5mg vial and larger mass configurations depends primarily on assay throughput, project timelines, and aliquot distribution strategies. The 5mg format is ideal for exploratory protocols, pilot animal studies, or specialized cell culture experiments requiring fresh solution preparation with minimal residual reagent waste.
Conversely, laboratories conducting large-scale high-throughput screening or multi-animal longitudinal studies may benefit from procuring larger fill sizes to reduce per-milligram unit costs and minimize lot-to-lot transition variables. For academic institutions, contract research organizations, and industrial laboratories managing high-volume operations, custom order sizes and bulk tier structures can be arranged through our dedicated wholesale portal.
Endotoxin Testing and Bio-Assay Integrity
In cell culture assays and sensitive preclinical animal models, bacterial endotoxin contamination poses a severe threat to experimental validity. Gram-negative bacterial lipopolysaccharides (LPS) can trigger non-specific inflammatory signaling, alter cytokine production, and confound data concerning melanocortin receptor activation pathways.
PX1 Research enforces stringent endotoxin limits on all research-grade peptide lots using standardized Limulus Amebocyte Lysate (LAL) chromogenic assays. Every batch is certified to contain endotoxin levels well below established regulatory thresholds (typically <0.1 EU/mg). This rigorous quality benchmark guarantees that observed biological phenomena can be attributed entirely to target melanocortin receptor engagement rather than background immunogenic contamination. Additional research insights and methodology guides can be explored within our public research library.
Frequently Asked Questions
What is the physical state and composition of a 5mg PT-141 vial?
A 5mg PT-141 vial contains a sterile, freeze-dried (lyophilized) solid cake consisting of pure Bremelanotide acetate synthesized to >99% purity, formulated with a non-interfering mannitol matrix for structural stabilization.
How do I calculate the working concentration of PT-141 5mg after reconstitution?
Divide the total mass (5,000 µg) by the diluent volume in milliliters. Adding 1.0 mL yields 5.0 mg/mL (5,000 µg/mL), 2.0 mL yields 2.5 mg/mL (2,500 µg/mL), and 3.0 mL yields approximately 1.67 mg/mL (1,666.7 µg/mL).
What primary receptor targets are investigated using PT-141 in preclinical models?
PT-141 is studied as a synthetic agonist targeting central melanocortin receptors, showing primary affinity for MC3R and MC4R subtype receptors involved in central neuroendocrine signaling.
How does PT-141 differ structurally and functionally from Melanotan II?
While derived from Melanotan II, PT-141 lacks the C-terminal amide group, reducing its relative binding affinity for cutaneous MC1R pigment receptors while maintaining potent central MC3R/MC4R receptor agonism.
What is the recommended storage temperature for un-reconstituted PT-141 5mg vials?
Lyophilized vials should be stored at -20°C or colder in a dry, dark environment to maintain compound stability for up to 24 months.
How long can reconstituted PT-141 remain stable in liquid solution?
When reconstituted with 0.9% bacteriostatic water, liquid solutions remain stable for up to 14–21 days stored at 2°C to 8°C. For long-term preservation, frozen micro-aliquots stored at -20°C are recommended.
Where can laboratories access third-party verification and COAs for PT-141?
Lot-matched Certificates of Analysis displaying HPLC chromatograms and Mass Spectrometry identity verification can be accessed directly on the PX1 Research COA lookup page.
Is PT-141 approved for human consumption or clinical administration?
No. PT-141 provided by PX1 Research is strictly designated for laboratory research use only by qualified investigators. It is not intended for human, clinical, or veterinary use.
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