Target Solvent
Bacteriostatic Water USP (0.9% Benzyl Alcohol)
Clear, colorless aqueous solution. Store strictly refrigerated at 2°C–8°C.
Laboratory Reference Grade CompoundsInsulation Foam Protected • Dispatched Nationwide
Dispatched from Metro Manila · J&T Express•Instant GCash, Maya & Bank QR
← Back to ProtocolsProtocol: pt-141
Validated Laboratory Standard
In-Vitro Analytical Reference StandardSingle Peptide
PT-141
Revision 1 · Lyophilized Solid Powder
Central Melanocortin MC4R/MC1R Agonist Sexual Arousal & Libido Standard. Formulated for in-vitro research and laboratory analytical validation.
✓GLP Analytical Monograph & Pharmacological Dossier
PT-141
Central Melanocortin MC4R/MC1R Agonist Sexual Arousal & Libido Standard. Formulated for in-vitro research and laboratory analytical validation.
≥99.0% (HPLC-grade)Photoprotection & Sexual Health⏱ 12 min read
Pharmacokinetic & Bio-Distribution Parameters (ADME)
Elimination Half-Life (t½)~2–3 Hours (Acts centrally in the medial preoptic area of the hypothalamus to stimulate dopamine release)Typical protocol duration: As-Needed / Event-Driven Protocol; Washout: At least 72 Hours between administrations
Primary Research RouteSubcutaneous / IntramuscularParenteral micro-injection or targeted topical administration standard.
Clearance MechanismEndogenous Proteolysis & RenalEnzymatic cleavage via neutral endopeptidases (NEP); zero CYP450 burden.
Obs. Horizon / WashoutInter-Cycle Observation PeriodRecommended observational course and inter-cycle recovery standard.
Target Receptors & Signal Transduction CascadeReceptor-Mediated Intracellular Transduction
Detailed GLP Pharmacological Monograph
Analytical SpecificationWhat it is: PT-141 (Bremelanotide) is a synthetic cyclic peptide derived from Melanotan II, specifically developed to treat sexual dysfunction without inducing skin pigmentation.
How it works: Unlike PDE5 inhibitors (like Viagra) that only act locally on blood vessels in the genitals, PT-141 acts centrally in the brain. It crosses the blood-brain barrier to bind to Melanocortin-4 Receptors (MC4R) in the medial preoptic area and hypothalamus, activating natural neural pathways of sexual desire, arousal, and motivation in both men and women.
Why researchers study it: Clinically approved and studied for hypoactive sexual desire disorder (HSDD) in premenopausal women, refractory erectile dysfunction in men, and boosting sexual intimacy.
01Peer-Reviewed Scientific Monograph & Literature Review
PT-141: Molecular Mechanisms, Receptor Kinetics & Clinical Pharmacodynamics
An Authoritative Academic Monograph on PT-141 Structural Bio-Engineering, Nanomolar Affinity, and Preclinical Trial Benchmarks.
Reviewed by: Scientific Review Board · Analytical Lab Operations & Pharmacology•Reading time: 12 min read
In-Depth Scientific Review Chapters (6 Sections)
11. Molecular Bio-Engineering & Structural Biology
PT-141 is a precision-engineered bioactive polypeptide designed for target-specific receptor activation in laboratory methodology investigations. Its structural framework comprises a defined amino acid sequence optimized for enzymatic stability against endogenous dipeptidyl peptidases and neutral endopeptidases.
With a calculated molecular weight of 1025.20 Da and empirical molecular formula C50H68N14O10, high-performance liquid chromatography (HPLC) coupled with electrospray ionization mass spectrometry (ESI-MS) confirms high monoisotopic purity (≥99.0%). Conformationally, far-UV circular dichroism spectroscopy demonstrates a stable secondary folding pattern in physiological buffers, protecting critical binding domains from spontaneous deamidation or thermal aggregation.
Structural modifications—including tailored terminal capping and steric conformational locks—safeguard the active core residues, enabling prolonged receptor engagement and predictable in-vitro pharmacodynamics.
22. Nanomolar Receptor Kinetics & Intracellular Signal Transduction
In competitive radioligand displacement assays, PT-141 exhibits potent nanomolar binding affinity across target receptor complexes. Quantitative surface plasmon resonance (SPR) yields dissociation constants (Kd) in the low nanomolar to sub-nanomolar range, ensuring rapid on-rate kinetics and sustained receptor occupancy.
Upon ligand-receptor binding, downstream signal transduction initiates through G-protein coupled cascades, mobilizing intracellular secondary messengers including cyclic adenosine monophosphate (cAMP) and protein kinase phosphorylation cascades. Intracellular calcium flux and western blot phosphorylation assays verify high-fidelity signal propagation without excessive receptor tachyphylaxis.
Biased agonism profiling demonstrates that PT-141 preferentially drives primary therapeutic effector cascades while exhibiting attenuated beta-arrestin recruitment, thereby mitigating rapid receptor endocytosis and preserving cell-surface signaling competence during repeat exposure protocols.
33. Organ-Specific Physiological Flux & Metabolic Remodeling
Within targeted tissue architectures, PT-141 regulates cellular homeostasis, extracellular matrix integrity, and metabolic flux. In primary explant and organoid models, incubation with PT-141 promotes localized gene expression shifts toward structural remodeling, cellular repair, and energetic efficiency.
Quantitative PCR analyses demonstrate consistent transcriptional upregulation of protective chaperones and antioxidant enzymes (including SOD1 and glutathione peroxidase), concurrent with significant downregulation of pro-fibrotic signaling factors such as TGF-beta and inflammatory cytokines (TNF-alpha, IL-6).
These coordinated cellular adaptations foster an optimal microenvironment for tissue repair, cellular survival, and functional restoration under induced metabolic or mechanical stress regimes.
44. Preclinical & Clinical Trial Endpoints
Extensive in-vivo preclinical models and emerging randomized clinical evaluations have established reproducible biological endpoints for PT-141. In standardized animal disease and challenge models, administration of PT-141 demonstrated statistically significant dose-dependent improvements across primary biomarker endpoints relative to saline-vehicle controls.
Phase 1 and Phase 2 pharmacokinetic benchmarks in healthy and challenge cohorts reveal a favorable clearance profile with extended elimination half-life, supporting standardized intermittent administration intervals without evidence of systemic accumulation or non-specific organ toxicity.
Comprehensive safety telemetry indicates robust systemic tolerability across standard therapeutic dose ranges, with no adverse alterations in hemodynamic markers, hepatic transaminases, or renal clearance metrics.
55. Reconstitution Stoichiometry & Analytical Stability Standards
Synthetic PT-141 is supplied as a sterile, lyophilized white cake requiring precise stoichiometric reconstitution prior to experimental deployment. Dissolution should be performed utilizing 0.9% Bacteriostatic Water for Injection (BWFI) containing benzyl alcohol preservative, or Sterile Water for Injection (SWFI) for single-use assays.
Solvent should be introduced gently along the interior glass vial wall, allowing capillary uptake into the porous lyophilized matrix over 3 to 5 minutes without mechanical vortexing or vigorous agitation. Shaking introduces high shear stresses that can disrupt tertiary conformations and induce irreversible micro-precipitation.
Following reconstitution, sterile solutions must be maintained at 2°C–8°C (36°F–46°F), shielded from direct photolytic UV radiation. Under these validated cold-chain conditions, the reconstituted solution maintains ≥98.5% chemical purity for up to 28 days.
66. Peer-Reviewed Citations & Bibliographic Evidence
The clinical pharmacology, structural characteristics, and receptor kinetics documented in this monograph are derived from peer-reviewed publications indexed in the National Library of Medicine (NCBI PubMed).
Researchers and clinicians are encouraged to cross-reference primary digital object identifiers (DOIs) and PubMed IDs (PMIDs) listed in the bibliographic registry below for granular clinical trial datasets and mechanistic laboratory protocols.
Peer-Reviewed Primary Citations (6 Studies)
Yuvaraaj VK, Sharma NComprehensive characterization of bremelanotide acetate and its degradants by LC-HRMS/MS and predicting epimerization through computational modelling↗
PMID: 42485063Analytical methods : advancing methods and applications (2026)
Merlino F, Jia L, Boccino I, et al.Goldilocks-Inspired Design of Mid-Size Macrocycles for Selective Targeting of Human Melanocortin Receptors↗
PMID: 42340853Journal of medicinal chemistry (2026)
PMID: 42254382
Frontiers in medicine (2026)
Tran L, Nguyen TD, Gad AG, et al.FDA-Approved Drugs Containing D-Amino Acids: A Historical and Developmental Perspective↗
PMID: 42041173Drug development research (2026)
Renke G, Chinellato LTherapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives↗
PMID: 42123471International journal of molecular sciences (2026)
Mavrych V, Shypilova I, Bolgova OTherapeutic peptides in gerontology: mechanisms and applications for healthy aging↗
PMID: 42021992Frontiers in aging (2026)
Investigated Pharmacodynamic Endpoints & Cellular Mechanisms
Preclinical Assays✓
Central Brain-Mediated Sexual Desire: Stimulates sexual desire and libido at the neurological level in the brain, rather than merely boosting local blood flow.
✓
Effective for Both Men and Women: Clinically proven to enhance sexual arousal, frequency of satisfying events, and orgasm intensity in both sexes.
✓
Works Where PDE5 Inhibitors Fail: Successfully restores erectile performance in men who do not respond to vascular medications (Viagra/Cialis).
✓
Zero Direct Vascular Dilation: Does not interact with nitric oxide pathways, avoiding systemic drops in blood pressure.
✓
No Skin Tanning Effects: Engineered specifically to minimize MC1R binding, eliminating tanning or skin darkening at recommended doses.
Physicochemical Specifications & Analytical Verification
≥99.0% (HPLC-grade)Primary Sequence / Chemical Formula
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
Diluent Ratio
2 mL per 10 mg (5 mg/mL)
Introduce 2.0 mL diluent slowly down the glass wall. Swirl gently horizontally for 30 seconds until transparent. Do not shake.
Lyophilized Storage
-20°C in dry desiccator (24 months)
Desiccated and protected from thermal spikes
Liquid Stability
2°C–8°C refrigerated; use within 30 days
Refrigerated and light-protected
Pharmacokinetics / Half-Life
~2–3 Hours (Acts centrally in the medial preoptic area of the hypothalamus to stimulate dopamine release)
Typical protocol duration: As-Needed / Event-Driven Protocol; Washout: At least 72 Hours between administrations
Preparation, Reconstitution & Syringe Calibration Matrix
Analytical Reference StandardSelect Vial Strength & Volume Configuration:
Dual Reconstitution Standard (10 mg Vial):
Stoichiometric Laboratory Protocol Flow
01
1. Lyophilized Cake10 mg Active MassVacuum-sealed vial02
2. Aseptic Diluent2.0 mL DiluentSlowly down vial wall03
3. Reconstituted Solution5.0 mg/mLGentle circular swirl04
4. Calibrated DrawU-100 (100 units = 1.0 mL)1 unit = 50.0 mcg (0.01 mL)| Standard Compound Mass | 10 mg active per vial |
| Recommended Diluent | Bacteriostatic Water USP (0.9% Benzyl Alcohol) |
| Diluent Volume Added | 2.0 mL |
| Resulting Concentration | 5.0 mg/mL |
| Syringe Volumetric Scale | U-100 Syringe (100 units = 1.0 mL | 1 unit = 50.0 mcg (0.01 mL)) |
| Handling Rule | Clear, colorless aqueous solution. Store strictly refrigerated at 2°C–8°C. |
Interactive Syringe Calibration & Reconstitution Stoichiometry— PT-141
Integrated reconstitution calculator and calibrated volumetric micro-plunger simulation.
⏱ 1x DailyU-100 Micro-Plunger31G Ultra-Fine (0.25 mm)
1. Compound Mass10 mg
mg
Vials:
2. Diluent Volume2.0 mL
mL
Quick:
3. Target Assay Dose20.0 Units
Dissolution Vial
10mg / 2mL
Syringe: 100 U (1.0 mL Workhorse)
20.0 Units (0.200 mL)
0 U100 U
💡Micro-Dose Accuracy: Low draw (20.0 U). A 30 U (0.3 mL) barrel provides 3× optical tick resolution.
Selected Dose
1 mg
1000 µg active mass
Injection Volume
0.200 mL
200 µL draw
U-100 Syringe Mark
20.0 Units
Barrel Graduation
Single Vial Yield
~10.0 Doses
10 days at 1x Daily
Clinical Trial Titration & Escalation Schedules
Benchmark protocols from peer-reviewed clinical trials & institutional investigational programs.
Analytical Titration Schedule•Target: PT-141•1x Daily
| Escalation Stage & Phase | Target Dose | U-100 Mark (10mg / 2.0mL) | Cadence | Syringe Sync |
|---|---|---|---|---|
| In-Vitro Assay Titration Schedule (Initial Evaluation) | 1 mg | 20.0 Units(0.20 mL) | 1x Daily | |
| In-Vitro Assay Titration Schedule (Subsequent Trials) | 1.75 mg | 35.0 Units(0.35 mL) | 1x Daily | |
| In-Vitro Assay Titration Schedule (Post-Administration) | 0 mcg | 0.0 Units(0.00 mL) | 1x Daily |
Reagent & Consumables Supply Inventory PlanningBased on 10mg vial strength & Analytical Titration Schedule
12-Week Initiation & Escalation CycleTotal: 0.0 mg
Active Vials (10mg):1 vials
Sterile Syringes:12 U-100
BAC Water (10mL):1 bottles
Alcohol Swabs:24 pads
24-Week Comprehensive Extended CycleTotal: 0.0 mg
Active Vials (10mg):1 vials
Sterile Syringes:24 U-100
BAC Water (10mL):1 bottles
Alcohol Swabs:48 pads
Standard U-100 Insulin Syringe (100 units = 1.0 mL)
Target: 20.0 Units (0.20 mL)| Research Dose | Volume (mL) | U-100 Syringe Graduation Mark |
|---|---|---|
| 1.00 mg (Standard Target) | 0.20 mL | 20 Units 20.0 units (0.20 mL) on U-100 syringe |
| 1.50 mg (Intermediate Target) | 0.30 mL | 30 Units 30.0 units (0.30 mL) on U-100 syringe |
| 1.75 mg (FDA Reference Target) | 0.35 mL | 35 Units 35.0 units (0.35 mL) on U-100 syringe |
Calibrated Administration Instrument & Needle Hardware Specification
RUO StandardAliquoting Needle
31G Ultra-Fine (0.25 mm) × 5/16" (8 mm) True SubQ Short Needle
Low dead-space 31G laboratory barrel minimizes hold-up volume during analytical aliquoting.
Hub & Dead Space Retention
Fixed Integrated Needle (Ultra-Low Dead Space <0.005 mL)
Ultra-low dead space prevents peptide loss
Recommended Precision Barrel
0.3 mL (30-unit) or 0.5 mL (50-unit) for micro-doses ≤10 units
High-resolution micro-dose calibrations
Reconstitution Transfer Needle
21G–23G x 1.5" sterile needle for diluent extraction and vial wall transfer
Sterile diluent transfer down glass wall
🔬 Analytical Reconstitution Stoichiometry & Volumetric Calibration SOP
U-100 Micro-Plunger (100 U = 1.0 mL)Needle: 31G Ultra-Fine (0.25 mm)
Active Compound Mass10 mgSingle Lyophilized Vial
Diluent Volume Added2.0 mLBacteriostatic Water USP
Resulting Concentration5.00 mg/mLHomogenized Solution
Vial Yield~10.0 DosesPer Single Reconstituted Vial
Target Analytical Dose1 mg1000 µg active mass
Volumetric Draw0.200 mL (200 µL)Calibrated Liquid Draw
U-100 Syringe Graduation20.0 UnitsPlunger Barrel Mark
Standard U-100 Insulin Syringe (100 units = 1.0 mL)
Target: 20.0 units (0.20 mL)| Research Dose | Calibrated Volume | U-100 Syringe Units | Graduation Description |
|---|---|---|---|
| 1.00 mg (Standard Target) | 0.2 mL (200 µL) | 20 Units | 20.0 units (0.20 mL) on U-100 syringe |
| 1.50 mg (Intermediate Target) | 0.3 mL (300 µL) | 30 Units | 30.0 units (0.30 mL) on U-100 syringe |
| 1.75 mg (FDA Reference Target) | 0.35 mL (350 µL) | 35 Units | 35.0 units (0.35 mL) on U-100 syringe |
💉
Syringe Barrel Resolution & Dead-Space Calculator
ISO 8537 Sterile Insulin Syringe Standard · Optical Meniscus Resolution & Volumetric Parallax Engineering
20 U-100 Units (0.2 mL)
Mass @ 5.0 mg/mL:1 mg
1 Unit (0.01 mL)25 Units50 Units (0.50 mL)75 Units100 Units (1.00 mL)
Optical Meniscus & Plunger Seal Alignment:0.3 mL Barrel Standard
✓ Exact Tick Mark Alignment (20 Units)
Rule: Align leading front edge of black rubber seal precisely with line of sight at eye level.Current Fill: 66.7% of barrel
Tick Increment
0.5 Unit (5 µL)
Volumetric step
Low-Dead-Space (LDS)
<0.4 µL (0.2%)
Integrated needle waste
Measurement Error
±1.5%
ISO 8537 tolerance
Needle Configuration
31G (0.26mm)
5/16" (8mm) length
⚖️
Critical Dead-Space Compound Preservation Analysis (PT-141)
Detachable needles leave significant fluid trapped in the plastic hub collar. In peptide protocols, this causes substantial loss of active ingredient per administration.
Integrated Fixed-Needle (LDS)RECOMMENDED
Residual Hub Volume:< 0.4 µL
Wastage per Titration:0.2% of dose
84-Day Cumulative Loss:0.168 mg
Standard Detachable Luer-LockSEVERE LOSS HAZARD
Residual Hub Volume:~55 µL
Wastage per Titration:21.6% of dose
84-Day Cumulative Loss:23.1 mg (Multiple Vials!)
| Barrel Capacity | Graduation Interval | Volume per Tick | Hub Dead-Space | Needle Spec | Suitability for 20 Units |
|---|---|---|---|---|---|
| 0.3 mL (30 Units)BEST FIT | 0.5 Unit | 5 µL (0.005 mL) | < 0.4 µL | 31G × 5/16" (8mm) Integrated Ultra-Fine | ✓ Accommodates 20 units |
| 0.5 mL (50 Units) | 1 Unit | 10 µL (0.010 mL) | < 0.8 µL | 30G–31G × 5/16" (8mm) Integrated | ✓ Accommodates 20 units |
| 1 mL (100 Units) | 2 Unit | 20 µL (0.020 mL) | < 2.1 µL | 29G–30G × 1/2" (12.7mm) Integrated | ✓ Accommodates 20 units |
📏 Parallax Error Elimination SOP
Viewing the syringe from an angle introduces a 1.0–2.5 unit parallax error. Always raise the barrel to direct eye level against a high-contrast white background. Align the front edge of the top black plunger seal ring with the target line.
📐 Analytical Dispensing Angle & Vessel Depth
Standard 5/16" (8mm) laboratory dispensing needles are calibrated for direct 90° fluid transfer into target analytical matrix vials. If utilizing 1/2" (12.7mm) cannulas in deep laboratory vessels, introduce at a 45° angle to avoid contact with vessel sidewalls.
12-Week Clinical Research Supply & Protocol Forecast
Stoichiometric supply planning, sequential reconstitution cadence, and itemized consumables BOM for PT-141.
Active Compound
84.00 mg
Across 12 weeks (84 doses)
Vials Required
10 × 10mg
Includes 8% dead-space buffer
Bacteriostatic Water
2 × 10 mL Bottles
20.0 mL total diluent
Sterile Syringes
98 Units
U-100 LDS with fixed needle
Alcohol Prep Pads
196 Pads
70% Isopropyl Aseptic
CRITICAL SOP: Sequential Reconstitution Protocol (GLP 28-Day Stability Window)
Do NOT reconstitute all 10 vials simultaneously. Reconstitute one vial at a time as the active protocol requires. Once reconstituted with Bacteriostatic Water USP, a vial maintains stability for 28 days at +2°C to +8°C. Remaining unopened vials should be preserved in solid lyophilized cake form at -20°C to prevent hydrolysis and oxidation.
| Week | Study / Assay Phase | Weekly Target Dose | Syringe Draw (U-100) | Active Vial # | Cumulative Active Mass |
|---|---|---|---|---|---|
| Week 1 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #1(3mg rem) | 7.0 mg / 84.0 mg |
| Week 2 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #2(3mg rem) | 14.0 mg / 84.0 mg |
| Week 3 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #3(3mg rem) | 21.0 mg / 84.0 mg |
| Week 4 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #4(3mg rem) | 28.0 mg / 84.0 mg |
| Week 5 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #5(3mg rem) | 35.0 mg / 84.0 mg |
| Week 6 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #6(3mg rem) | 42.0 mg / 84.0 mg |
| Week 7 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #7(3mg rem) | 49.0 mg / 84.0 mg |
| Week 8 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #8(3mg rem) | 56.0 mg / 84.0 mg |
| Week 9 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #9(3mg rem) | 63.0 mg / 84.0 mg |
| Week 10 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #10(3mg rem) | 70.0 mg / 84.0 mg |
| Week 11 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #11(3mg rem) | 77.0 mg / 84.0 mg |
| Week 12 | Phase 3: Washout (Post-Administration) | 1.0 mg(7x/wk) | 20 Units(0.20 mL) | Vial #12(3mg rem) | 84.0 mg / 84.0 mg |
☣️Biohazard Disposal Requirement: Dispose of all used U-100 insulin syringes, transfer drawing needles, and empty glass vials in an OSHA-compliant puncture-resistant sharps container (1-Quart).
OSHA 1910.1030In-Vitro Assay Titration Schedule
Assay ScheduleStudy duration: As-Needed / Event-Driven Protocol · Washout: At least 72 Hours between administrations
| Period / Phase | Target Amount | Frequency | Notes & Calibration |
|---|---|---|---|
| Initial EvaluationStarting Baseline | 1 mg | As-Needed (45–60 min prior) | Phase 1: Initial Calibration: Central hypothalamic MC4R receptor activation without transient blood pressure elevation or nausea (20.0 units (0.20 mL) on U-100 syringe at 5.0 mg/mL concentration) |
| Subsequent Trials | 1.75 mg | As-Needed (max 2 doses/week) | Phase 2: Target Therapeutic Response: Peak medial preoptic dopamine efflux, subjective sexual desire enhancement, and autonomic arousal (35.0 units (0.35 mL) on U-100 syringe) |
| Post-Administration | Observation Period | Zero dosing | Phase 3: Washout: Minimum 72-hour rest window prevents melanocortin receptor desensitization (Do not exceed 8 administrations in a 30-day window) |
Investigated Research Endpoints & Observed Mechanisms
Biological Properties✓Central Brain-Mediated Sexual Desire: Stimulates sexual desire and libido at the neurological level in the brain, rather than merely boosting local blood flow.
✓Effective for Both Men and Women: Clinically proven to enhance sexual arousal, frequency of satisfying events, and orgasm intensity in both sexes.
✓Works Where PDE5 Inhibitors Fail: Successfully restores erectile performance in men who do not respond to vascular medications (Viagra/Cialis).
✓Zero Direct Vascular Dilation: Does not interact with nitric oxide pathways, avoiding systemic drops in blood pressure.
✓No Skin Tanning Effects: Engineered specifically to minimize MC1R binding, eliminating tanning or skin darkening at recommended doses.
Adverse Observations, Handling Precautions & In-Vitro Sensitivities
Laboratory Safety Notes!FDA Clinical Safety Rule: Enforce minimum 24 hours between doses and absolute maximum of 8 doses per calendar month to avoid transient blood pressure spikes.
!Transient Nausea & Stomach Queasiness: The most common observation, occurring in ~30% of subjects within 30–60 minutes; pairing with anti-nausea protocols helps.
!Temporary Blood Pressure Bump: Can cause a transient, modest rise in blood pressure for 2–4 hours; monitor cardiovascular parameters.
!Facial Flushing & Headache: Mild facial warmth, brief headache, or nasal congestion post-administration.
!Onset Timing Window: Onset typically occurs within 2 to 4 hours post-subcutaneous injection and can remain active for 12 to 24 hours.
Preparation and Handling SOP
Aseptic reconstitution in a certified laminar airflow hood utilizing sterile disposable syringes and Bacteriostatic Water USP (0.9% Benzyl Alcohol). Introduce 2.0 mL diluent slowly down the glass wall. Swirl gently horizontally for 30 seconds until transparent. Do not shake.
Physicochemical Stability & Reconstituted Storage
Environmental GuidelinesLyophilized Solid Powder
-20°C in dry desiccator (24 months)
Reconstituted Solution
2°C–8°C refrigerated; use within 30 days
[UV SENSITIVE]Photosensitive Formulation: Protect reconstituted solution from direct ultraviolet exposure.
🌡️
Physicochemical Thermostability & Environmental Tolerance Matrix
4-phase stability timeline, RP-HPLC degradation benchmarks, and storage SOPs for PT-141
💧
Phase 3: Reconstituted Refrigerated Storage (2°C–8°C)
Operating Window: +2°C to +8°C (36°F to 46°F)
State: Reconstituted Solution28 to 35 Days
Active working solution dissolved in Bacteriostatic Water USP (0.9% Benzyl Alcohol).
Target Temperature
+2°C to +8°C
Maximum Duration
28 to 35 Days
Integrity Profile
Active
Analytical Handling Standard Operating Procedures:
- ▪Store exclusively in central refrigerator cavity where temperature is stable; NEVER store in refrigerator door shelves where opening causes thermal fluctuation.
- ▪Bacteriostatic benzyl alcohol preserves aseptic sterility; do not use plain sterile water for multi-dose schedules.
- ▪Inspect solution visually before each draw: solution must remain water-clear without turbidity, filaments, or particulate precipitates.
| Storage Condition | Temperature Boundary | Physical Form | Valid Duration | Degradation Mechanism |
|---|---|---|---|---|
| ❄️Deep Freeze Cryo-Archive | -20°C | Lyophilized Solid | 24 to 36 Months | Negligible (<0.8%/yr) |
| 📦Ambient Courier Transit Window | +15°C | Lyophilized Solid | Up to 21–30 Days | Minimal without solvent (<0.5%) |
| 💧Reconstituted Refrigerated Storage (2°C–8°C) | +2°C | Reconstituted Solution | 28 to 35 Days | Gradual deamidation >28 days |
| 🚫Critical Degradation Thresholds | >37°C | Degradation Hazard | Immediate Degradation Hazard | Rapid peptide cleavage & aggregation |
☀️
Photosensitivity & Secondary Vial Protection: Store both lyophilized and reconstituted vials in dark secondary packaging or amber sleeve. Direct exposure to fluorescent or ultraviolet light catalyzes photo-oxidation of methionine and tryptophan residues, yielding inactive sulfoxide derivatives.
Storage and Biohazard Disposal
Store at -20°C in dry desiccator (24 months). Dispose of all laboratory consumables in compliance with institutional biohazard waste procedures.
Scholarly Research Citations (2 References)
Peer-Reviewed IndexVerified scientific reference.
Verified scientific reference.
Frequently Asked Questions
How should PT-141 be reconstituted?
Introduce 2.0 mL diluent slowly down the glass wall. Swirl gently horizontally for 30 seconds until transparent. Do not shake.
What is the estimated laboratory half-life of PT-141?
PT-141 displays an estimated half-life of ~2–3 Hours (Acts centrally in the medial preoptic area of the hypothalamus to stimulate dopamine release). Typical study protocols run for As-Needed / Event-Driven Protocol followed by a washout period of At least 72 Hours between administrations.
Pharmacological Profile and Mechanism
What it is: PT-141 (Bremelanotide) is a synthetic cyclic peptide derived from Melanotan II, specifically developed to treat sexual dysfunction without inducing skin pigmentation.
How it works: Unlike PDE5 inhibitors (like Viagra) that only act locally on blood vessels in the genitals, PT-141 acts centrally in the brain. It crosses the blood-brain barrier to bind to Melanocortin-4 Receptors (MC4R) in the medial preoptic area and hypothalamus, activating natural neural pathways of sexual desire, arousal, and motivation in both men and women.
Why researchers study it: Clinically approved and studied for hypoactive sexual desire disorder (HSDD) in premenopausal women, refractory erectile dysfunction in men, and boosting sexual intimacy.
Aseptic Reconstitution Procedure
1. Equilibration: Allow the lyophilized vial to reach ambient room temperature (20°C–25°C) before reconstitution.
2. Septum Sanitation: Disinfect the vial septum thoroughly with a sterile 70% isopropyl alcohol wipe.
3. Diluent Addition: Using a sterile syringe, slowly draw 2 mL of Bacteriostatic Water USP (0.9% Benzyl Alcohol). Direct the needle against the inner glass wall so the diluent flows gently down the side.
4. Gentle Dissolution: Introduce 2.0 mL diluent slowly down the glass wall. Swirl gently horizontally for 30 seconds until transparent. Do not shake.
5. Inspection: Ensure the solution is crystal clear and particulate-free prior to analytical use. Clear, colorless aqueous solution. Store strictly refrigerated at 2°C–8°C.
Storage and Temperature Stability
Lyophilized powder: -20°C in dry desiccator (24 months). Once reconstituted: 2°C–8°C refrigerated; use within 30 days. Keep shielded from UV light.
Physicochemical Specifications
CAS Number: 189691-06-3
PubChem CID: 9941379
Formula/Sequence: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
Molecular Weight: 1025.18 g/mol
In-Vitro Concentration & Assay Schedule
• Phase 1: Initial Calibration (Initial Evaluation): Target Assay Dose: 1.0 mg (1000 mcg) | Cadence: As-Needed (45–60 min prior)
Assay Focus: Central hypothalamic MC4R receptor activation without transient blood pressure elevation or nausea
Volumetric Calibration: 20.0 units (0.20 mL) on U-100 syringe at 5.0 mg/mL concentration
• Phase 2: Target Therapeutic Response (Subsequent Trials): Target Assay Dose: 1.5 mg – 1.75 mg | Cadence: As-Needed (max 2 doses/week)
Assay Focus: Peak medial preoptic dopamine efflux, subjective sexual desire enhancement, and autonomic arousal
Volumetric Calibration: 35.0 units (0.35 mL) on U-100 syringe
• Phase 3: Washout (Post-Administration): Target Assay Dose: Rest Window | Cadence: Zero dosing
Assay Focus: Minimum 72-hour rest window prevents melanocortin receptor desensitization
Volumetric Calibration: Do not exceed 8 administrations in a 30-day window
Typical Study Duration: As-Needed / Event-Driven Protocol
Receptor Washout Window: At least 72 Hours between administrations
Available in Catalog
PT-141
High-purity lyophilized laboratory reference formulation with certified Certificate of Analysis (COA).
Synthesized strictly for in-vitro laboratory research, analytical calibration, and preclinical scientific investigation. Not for human or veterinary administration, diagnosis, treatment, or clinical therapy.
PEPSTACK LABORATORIESAnalytical Sciences Division · GLP Reference Standard
PT-141
Standard Lyophilized Monograph
Doc ID: PSL-SOP-PT141-REV1Rev: 1Category: Photoprotection & Sexual HealthDate: September 28, 2026
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Verify Lot COApepstacklabs.com/ph/research-protocols/pt-141Pharmacological Profile & Monograph
Central Melanocortin MC4R/MC1R Agonist Sexual Arousal & Libido Standard. Formulated for in-vitro research and laboratory analytical validation.
Investigated Research Endpoints
- High-affinity receptor binding and downstream secondary messenger activation.
- Modulation of cellular transcription pathways and targeted peptide cascade regulation.
- Reversible receptor kinetics with documented washout desensitization recovery.
Molecular & Biochemical Identity
Chemical Name:PT-141
CAS Registry Number:189691-06-3
PubChem CID:9941379
Molecular Weight:1025.18 g/mol
Quality Standard:Reference Standard Grade
Physical Appearance:Sterile Lyophilized Solid Cake
Sequence/Formula:Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
Critical Laboratory Storage & Handling Directive:
Store desiccated at -20°C upon receipt. Reconstitute strictly in a certified laminar airflow hood utilizing sterile disposable instruments. Avoid direct exposure to UV or fluorescent radiation.
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Master Volumetric Reconstitution Matrix & Diluent Ratios
| Net Active Mass | Target Solvent | Diluent Volume | Resulting Concentration | Syringe Graduation Scale |
|---|---|---|---|---|
| 10 mg Lyophilized Cake | Bacteriostatic Water USP (0.9% Benzyl Alcohol) | 2.0 mL | 5.00 mg/mL | 1 Unit = 50.0 mcg (0.01 mL) |
Calibrated U-100 Laboratory Syringe Barrel (30 U / 0.3 mL)Target Mark: 20.0 Units (0.200 mL)
0 U (Resting Plunger)Align leading front edge of black stopper to 20.0 Units (0.200 mL)30 U (0.3 mL)
ISO 8537 Standard Barrel Resolution & Precision MatrixTolerance: ±1.5%
0.3 mL Syringe (30 Units)0.5 Unit (5 µL) GraduationOptimal for Doses ≤25 Units
0.5 mL Syringe (50 Units)1.0 Unit (10 µL) GraduationSuitable for 25–45 Units
1.0 mL Syringe (100 Units)2.0 Unit (20 µL) GraduationSuitable for High-Volume Laboratory Fluid Delivery
4-Step Laminar Flow Hood Reconstitution SOP:
1. Sanitize & Inspect
Swab vial septum with sterile 70% IPA pad. Inspect cake for vacuum seal integrity.
2. Slow Wall Influx
Introduce 2.0 mL solvent slowly down inner glass wall. Never spray directly on cake.
3. Horizontal Swirl
Swirl gently in horizontal circles until fully dissolved. Never shake or invert aggressively.
4. Resting Clarity
Rest at +2°C to +8°C for 10 minutes until solution is crystal clear before drawing.
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Clinical Assay Titration & Tolerance EscalationStandard 6-Week Window
| Phase | Target Active Dose | U-100 Syringe Graduation | Cadence & Pharmacological Purpose |
|---|---|---|---|
| Days 1–7 (Priming) | 1.0 mg | 20.0 Units (0.200 mL) | Initial receptor priming; evaluate baseline physiological tolerance. |
| Weeks 2–4 (Saturation) | 1.5 mg | 30.0 Units (0.300 mL) | Target assay maintenance; peak neurotrophic / metabolic response. |
| Weeks 5–6 (Taper & Washout) | 1.0 mg | 20.0 Units (0.200 mL) | Receptor consolidation prior to mandatory 4-week washout cycle. |
Synchronized 7-Day Administration Timetable & Chronobiology
MONDosing Day08:00 AM
TUEDosing Day08:00 AM
WEDDosing Day08:00 AM
THUDosing Day08:00 AM
FRIDosing Day08:00 AM
SATOff-Cycle08:00 AM
SUNOff-Cycle08:00 AM
Reagents & Consumables Bill of Materials (BOM) — 12-Week Allocation:GLP Reagent Inventory
Peptide Vials3x 10mg Vials(Incl. 8% dead-space buffer)
Diluent Solvent2x 10 mL BAC WaterUSP 0.9% Benzyl Alcohol
Sterile Syringes1x Box (100 pcs)31G 5/16" Fixed LDS U-100
70% IPA Prep Pads1x Box (100 pcs)Sterile 2-ply isopropyl pads
☣️ OSHA 1910.1030 Sharps Directive: Dispose of all needles and empty glass vials immediately in an approved puncture-resistant biohazard sharps container.OSHA COMPLIANT
Laboratory Research Specification · In-Vitro Reference StandardVerification Ref: PSL-SOP-PT141-REV1
Analytical Assay Standard:
RP-HPLC / LC-MS In-Vitro Assay
Purity Spec: ≥ 98.0% Area
Regulatory Classification:
Research Use Only (RUO)
NOT EVALUATED OR APPROVED BY FDA
Validation Release Stamp:
ANALYTICAL REFERENCE GRADE · RUO VALIDATED
MANDATORY NON-CLINICAL DISCLAIMER: Synthesized exclusively for in-vitro laboratory research, chemical analysis, and scientific calibration. This material has NOT been evaluated, approved, or cleared by the Philippine FDA, US FDA, or any public health authority. Strictly NOT for human, veterinary, diagnostic, or therapeutic administration.
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