Oxytocin 5mg — Vial Spec, Reconstitution Math & COA

Overview of the Oxytocin 5mg Research Specification

A 5mg vial of lyophilized oxytocin contains exactly 5.0 milligrams of the synthetic cyclic nonapeptide C43H66N12O12S2 (molecular weight ~1007.19 g/mol) in a sterile, nitrogen-flushed borosilicate glass vial. This standard unit mass is routinely ordered by academic, biopharmaceutical, and contract research organizations (CROs) conducting intermediate-scale benchwork. It provides a balanced yield—offering sufficient material for multiple replicate microplate binding assays, receptor density mapping, or acute rodent behavioral models without exposing excessive peptide quantity to repeated room-temperature degradation.

In analytical chemistry and receptor pharmacology, a single 5mg unit provides 4.96 micromoles of pure peptide target material. This allows investigators to prepare stock solutions in the millimolar (mM) range and subsequent working dilutions in the nanomolar (nM) range required for high-affinity oxytocin receptor (OXTR) characterization.

PX1 Research maintains rigorous manufacturing specifications across all nonapeptide formats. Although certain specialized bulk runs produce 5mg fills, our primary stocked catalog item for immediate dispatch is the oxytocin 10mg vial. Investigators requiring distinct mass fills, custom lot allocations, or bulk ordering for expanded experimental protocols can cross-reference our complete inventory in the all peptides catalog or consult our wholesale department for institutional procurement.

Reconstitution Mathematics for 5mg Lyophilized Mass

Accurate reconstitution of a 5mg lyophilized peptide cake requires precise volume measurement to achieve desired working concentrations. The fundamental mathematical relationship governing peptide concentration is Concentration (C) = Mass (m) / Volume (V). For a fixed mass of 5.0 mg (5000 micrograms), varying the diluent volume yields distinct concentration profiles suitable for specific laboratory assays.

When adding 1.0 mL of sterile bacteriostatic water or laboratory-grade 0.9% sodium chloride, the final concentration is 5.0 mg/mL (5000 µg/mL or 5.0 µg/µL). This dense stock solution is highly efficient for long-term frozen storage in minimal volume, minimizing freezer footprint and plastic surface adsorption.

Adding 2.0 mL of diluent dilutes the mixture to 2.5 mg/mL (2500 µg/mL or 2.5 µg/µL). This concentration simplifies volumetric pipetting when dosing micro-liter aliquots into culture media or tissue bath preparations, reducing pipetting margin-of-error during rapid assay setups.

When 3.0 mL of solvent is introduced, the resultant concentration is 1.67 mg/mL (1666.67 µg/mL or ~1.67 µg/µL). This lower density is frequently preferred for automated liquid handling workstations where larger aspirated volumes increase delivery precision across 96-well or 384-well microplates.

For complex dilution schemes or custom target concentrations, laboratory staff can streamline calculations using our interactive reconstitution calculator tool to verify microgram-to-microliter conversions prior to laboratory execution.

Aliquot Planning and Cryogenic Storage Protocols

Lyophilized oxytocin demonstrates exceptional solid-state stability when stored under controlled environment conditions. Sealed vials received from PX1 Research should be stored at -20°C in a desiccated environment, shielded from light. Under these conditions, the unconstitution nonapeptide maintains structural integrity and bioactivity for up to 24 months from the manufacturing fill date.

Once reconstituted, aqueous peptide solutions become significantly more susceptible to hydrolytic cleavage, deamidation, and disulfide bond scrambling. To maximize stability, working solutions must never undergo repeated freeze-thaw cycles. Freezing and thawing ice crystals create physical shear stress that disrupts tertiary peptide conformation and accelerates aggregation.

A rigorous aliquot protocol involves immediately dividing the freshly reconstituted solution into single-use, low-binding polypropylene microcentrifuge tubes. Aliquot volume should match the exact volumetric requirement of a single experimental run (e.g., 50 µL to 200 µL). Working aliquots intended for use within 24 to 48 hours may be maintained at 2°C to 8°C. Long-term liquid storage requires immediate deep-freezing at -20°C or -80°C, where solution integrity can be preserved for several months.

To minimize peptide loss due to non-specific binding on container walls, investigators should utilize hydrophobic, ultra-low retention plasticware or include non-interfering carrier proteins (such as 0.1% Bovine Serum Albumin) in non-sensitive assay buffers.

Analytical Verification: COA, HPLC, MS, and Endotoxin Standards

Assay reproducibility in biomedical research depends entirely on compound purity and lot-to-lot consistency. PX1 Research enforces strict quality assurance parameters for every peptide batch produced in our cGMP-compliant, USA-based manufacturing facilities.

Every production lot undergoes rigorous analytical testing at an independent, ISO 17025-accredited laboratory. Analytical verification includes High-Performance Liquid Chromatography (HPLC) to establish peptide purity, confirming a baseline purity threshold of ≥98.0%. Mass Spectrometry (MS) analysis verifies exact molecular weight, matching the theoretical mass of 1007.19 Da to ensure the correct sequence synthesis without missing amino acid residues.

Because oxytocin is frequently studied in sensitive cell cultures and animal tissue models, bacterial endotoxin content must be strictly controlled. Residual lipopolysaccharides (LPS) can trigger non-specific inflammatory signaling pathways, skewing experimental results. PX1 Research subjects every lot to Limulus Amebocyte Lysate (LAL) testing, verifying endotoxin levels well below industry thresholds (<0.01 EU/mg).

Laboratory personnel can review or download complete, lot-matched analytical documentation directly through our dedicated COA verification hub by entering the batch number printed on the vial label.

Comparative Analysis: Selecting 5mg vs. 10mg Mass Formats

Choosing the appropriate vial size requires balancing experimental throughput, storage logistics, and cost efficiency. While the oxytocin 5mg format is ideal for low-volume preliminary studies or specialized single-assay validation, larger mass options offer significant operational advantages for high-throughput screening.

A 5mg vial minimizes the risk of product loss due to unexpected contamination or degradation of reconstituted liquid during prolonged testing windows. It is particularly suitable for laboratories performing infrequent binding studies or pilot animal cohorts where total mass consumption remains low.

Conversely, selecting our standard oxytocin 10mg formulation reduces per-milligram supply costs and decreases the frequency of batch-to-batch reconstitution steps. For institutional facilities managing continuous experimental pipelines or large rodent cohorts, higher mass vials eliminate reconstitution variance across multiple smaller vials. Researchers can evaluate overall research requirements across our research peptides catalog to optimize inventory planning.

Mechanistic Overview in Preclinical Research Models

Oxytocin is a classic neurohypophyseal nonapeptide featuring a conserved disulfide bridge between Cys1 and Cys6, creating a six-amino-acid cyclic ring with a three-amino-acid C-terminal tail (Pro-Leu-Gly-NH2). Preclinical studies suggest that this cyclic structure is critical for high-affinity binding to the G-protein coupled Oxytocin Receptor (OXTR).

In vitro data indicate that OXTR activation initiates downstream signaling cascades primarily mediated by Gq/11 proteins, triggering phospholipase C-beta (PLCβ) activation, inositol trisphosphate (IP3) production, and intracellular calcium mobilization. In neural tissue preparations, this cascade modulates synaptic plasticity, GABAergic interneuron firing, and central neurotransmitter release.

Animal studies demonstrate that central and peripheral oxytocin signaling regulates diverse physiological systems, ranging from smooth muscle contraction dynamics in reproductive tissues to complex social modulation, stress buffering via the hypothalamic-pituitary-adrenal (HPA) axis, and metabolic energy homeostasis. Investigators utilize purified oxytocin compounds to delineate specific receptor subtype selective responses and downstream kinase cascades in cell-based assays.

Topical Structural Comparison: Nonapeptide Homologs and Analogs

When designing neuroendocrine or vascular signaling assays, researchers frequently compare oxytocin against structurally related neurohypophyseal peptides and synthetic analogs. The table of homologous compounds includes vasopressin, carbetocin, and desmopressin.

Arginine vasopressin differs from oxytocin by only two amino acids (Phe3 instead of Ile3, and Arg8 instead of Leu8), yet this structural divergence shifts receptor selectivity toward V1a, V1b, and V2 receptors, governing vasoconstriction and renal water retention. Carbetocin acts as a long-acting synthetic oxytocin agonist featuring a thioether modification that increases resistance to enzymatic cleavage by uterine peptidases. Desmopressin represents a modified vasopressin analog engineered for high V2 receptor selectivity with minimal pressor activity.

Evaluating these structural analogs side-by-side in competitive binding assays allows investigators to map amino acid residues responsible for receptor selectivity, internalization rates, and downstream signaling bias across the rhodopsin-like GPCR family.

Reconstitution and Handling Best Practices for Assay Reproducibility

Achieving consistent quantitative outcomes in peptide assays requires strict adherence to reconstitution protocols. Before removing the aluminum flip-off seal, sanitize the rubber stopper with a 70% isopropyl alcohol wipe and allow it to air-dry completely in a laminar flow hood.

Aspirate the desired volume of sterile solvent—typically Bacteriostatic Water (containing 0.9% benzyl alcohol as a preservative) or sterile 0.9% Sodium Chloride—using a precise laboratory syringe. Insert the needle through the center of the stopper, directing the liquid stream down the glass inner wall rather than directly onto the lyophilized cake.

Allow the solvent to naturally saturate the lyophilized powder. Gently swirl the vial in a circular motion to facilitate dissolution. Never vortex or vigorously shake peptide solutions, as mechanical shear forces at liquid-air interfaces cause protein denaturing, aggregation, and loss of biological activity.

Confirm that the solution is clear, colorless, and free of visible particulate matter before proceeding to aliquoting or working dilution steps. Refer to our step-by-step reconstitution guide for comprehensive standard operating procedures.

PX1 Research Quality Assurance & Supply Chain Operations

PX1 Research operates as a trusted USA-based supplier dedicated exclusively to supporting academic institutions, biotechnology enterprises, and government research laboratories. We do not supply compounds for human, clinical, or veterinary applications.

Our state-of-the-art synthesis infrastructure operates under strict ISO 9001 and cGMP-compliant quality management systems. Every peptide lot is subjected to dual-stage HPLC and Mass Spectrometry validation to guarantee uniform sequence purity, correct mass, and minimal batch variance.

To prevent thermal degradation during transit, orders are packed in temperature-controlled, insulated packaging and dispatched via same-day shipping (Monday through Friday) from our centralized distribution facilities in California and Arizona. This dual-hub logistics structure ensures rapid delivery to research laboratories across the United States, preserving compound integrity from synthesis to benchtop.