PT-141 50mg — Vial Spec, Reconstitution Math & COA

Specification & Availability: PT-141 50mg Bulk Vial Format

The 50mg vial format of PT-141 (Bremelanotide) represents a high-mass lyophilized yield formulated specifically for high-throughput laboratory assays, multi-plate receptor binding screens, or automated liquid handling platforms. In contrast to standard analytical sizes, a 50mg lyophilized cake requires distinct reconstitution math and aliquot planning to prevent concentration gradients and limit freeze-thaw degradation cycles during extended testing windows.

While PX1 Research manufactures standard catalog inventory in single-use and multi-dose configurations such as our verified PT-141 10mg vials, high-mass specifications like the 50mg variant are frequently utilized by institutional laboratories conducting high-volume binding assays. Investigators requiring custom fills, bulk master-lot batches, or specialized unit quantities can evaluate our complete catalog of all peptides or consult our institutional team for high-volume allocations.

Chemical Identity & Receptor Agonism Profile

PT-141, chemically designated as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH, is a synthetic cyclic heptapeptide derived from the alpha-melanocyte-stimulating hormone (α-MSH) structure. Unlike linear precursor peptides, the cyclic lactam bridge between Asp3 and Lys8 confers enhanced enzymatic stability against vascular and tissue endopeptidases in preclinical models.

As a non-selective melanocortin receptor agonist, PT-141 exhibits primary affinity for the melanocortin-4 receptor (MC4R) and melanocortin-3 receptor (MC3R), with lower binding affinity for MC1R and MC5R. In vitro receptor binding assays indicate that PT-141 operates via G-protein coupled receptor (GPCR) activation, stimulating intracellular adenylate cyclase and elevating cyclic adenosine monophosphate (cAMP) levels. Preclinical research models investigate these signaling cascades within central nervous system nuclei—specifically the paraventricular nucleus (PVN) of the hypothalamus—to map neural circuits regulating autonomic and neuroendocrine responses.

Reconstitution Math for 50mg Lyophilized Vials

Reconstituting a 50mg lyophilized peptide cake requires careful volume selection based on the sensitivity of target liquid handling systems and the micro-volumetric precision of analytical instrumentation. Because 50mg is a substantial mass of peptide powder, adequate solvent must be introduced to achieve complete dissolution without creating an excessively hypertonic or viscous stock solution.

When preparing stock solutions from a 50mg vial, researchers typically select between 1.0 mL, 2.0 mL, or 3.0 mL of sterile diluent (such as Bacteriostatic Water containing 0.9% benzyl alcohol or Sterile Normal Saline). Below is the resulting concentration matrix for common reconstituted volumes:

• Reconstitution with 1.0 mL diluent yields a stock concentration of 50.0 mg/mL (50.0 µg/µL). • Reconstitution with 2.0 mL diluent yields a stock concentration of 25.0 mg/mL (25.0 µg/µL). • Reconstitution with 3.0 mL diluent yields a stock concentration of 16.67 mg/mL (16.67 µg/µL). • Reconstitution with 5.0 mL diluent yields a stock concentration of 10.0 mg/mL (10.0 µg/µL).

To calculate custom dilution ratios, working assay concentrations, or serial dilution steps for microplate wells, utilize our interactive reconstitution calculator. Accurate volumetric math prevents pipetting error propagation in downstream spectrophotometric or radiometric assays.

High-Yield Aliquoting & Storage Protocols

Repeated freeze-thaw cycles significantly accelerate peptide backbone cleavage and aggregation in reconstituted aqueous solutions. For 50mg vials, standard operating procedure dictates immediate sub-aliquoting into single-use microcentrifuge tubes immediately following initial reconstitution and full dissolution.

Lyophilized PT-141 powder should be stored upon receipt in a desiccated environment at -20°C for short-term preservation or -80°C for long-term stability. Once reconstituted, stock solutions in bacteriostatic diluent remain stable for up to 28 days under refrigeration at 2°C to 8°C. If aliquoted into sterile polypropylene cryovials and flash-frozen at -80°C, working stock can be preserved for extended assay schedules, provided individual aliquots are thawed only once prior to experimental use.

Analytical Quality Control & Lot-Matched COA Verification

Every production lot of PT-141 manufactured for PX1 Research undergoes strict analytical validation in ISO 17025 accredited third-party laboratories. Quality verification is never inferred from raw material supplier claims; each finished batch is independently tested to guarantee exact chemical identity and purity.

Analytical protocols include High-Performance Liquid Chromatography (HPLC) to confirm structural purity (exceeding 99.0%), Mass Spectrometry (MS) to verify precise molecular weight (1024.2 g/mol), and Chromogenic Endotoxin Testing (LAL assay) to ensure levels remain well under strict research thresholds (<0.05 EU/mg). Researchers can review and download lot-matched certificates directly via our transparent COA database.

Comparative Analysis: Melanocortin Receptor Agonists

In melanocortin receptor research, structural modifications alter target selectivity, receptor activation duration, and systemic signaling profiles. Evaluating PT-141 alongside related synthetic analogues clarifies its distinct position in receptor pharmacology.

When comparing melanocortin peptides, PT-141 (Bremelanotide) is differentiated from non-selective precursors like Melanotan II and primary agonists such as Afamelanotide (Melanotan I). While Melanotan II exhibits potent affinity for MC1R, MC3R, MC4R, and MC5R—triggering both melanogenesis and central neural responses—PT-141 is a hydroxylated metabolite derivative designed to reduce MC1R-mediated cutaneous pigmentation activation while retaining robust central MC3R and MC4R signaling. Afamelanotide operates predominantly as an MC1R-selective agonist for photoprotection models, whereas PT-141 is primarily investigated for melanocortin-receptor signaling linked to central neuroendocrine and sexual-health pathways in rodent models.

In Vitro & Preclinical Receptor Binding Studies

Preclinical literature demonstrates that PT-141 acts within the central nervous system rather than directly on peripheral vascular smooth muscle. In vitro radioperfusion assays and competitive binding studies show high affinity for central MC4R sites located in the hypothalamus.

Animal studies suggest that central administration of PT-141 triggers downstream dopamine release in the medial preoptic area (mPOA) and nucleus accumbens via neuroanatomical projections from melanocortin-expressing neurons. Experimental models evaluating central melanocortin signaling utilize PT-141 to map the intersection between peptide GPCR binding, central neurotransmitter turnover, and autonomic output mechanisms.

Selecting the Right Format: 10mg vs. 50mg Vials

Selecting the appropriate package size depends on protocol scale, liquid handler dead volume, and usage velocity. For exploratory pilot studies, single-target binding assays, or small animal cohorts, ordering standard single vials like the PT-141 10mg format minimizes waste and reduces reconstituted storage duration.

Conversely, high-volume screening operations, automated assay screening facilities, and multi-center research projects benefit from high-mass configurations or institutional fulfillment. Research institutions requiring customized fill sizes, consistent single-lot allocations, or commercial quantity tiers are encouraged to explore our dedicated wholesale laboratory program or browse our extensive research library hub for comparative trial data.