What primary receptor cascades and in vitro signaling axes are modulated by PT-141 (Bremelanotide)?

Pre-clinical studies indicate PT-141 (Bremelanotide) engages primary pathways: Selective agonist for central melanocortin MC3R and MC4R G-protein coupled receptors. Stimulates downstream central neurotransmission pathways in the medial preoptic area of the hypothalamus. Additional investigations explore cellular migration, receptor binding affinities, and kinase activation in vitro.

What is the recommended reconstitution diluent and sterile handling protocol for PT-141 (Bremelanotide)?

Lyophilized PT-141 (Bremelanotide) cakes must be reconstituted using Bacteriostatic 0.9% Benzyl Alcohol USP or Sterile Reconstitution Diluent. Introduce the diluent gently along the internal glass wall under a laminar flow hood, allowing passive dissolution without mechanical vortex shear or high-velocity liquid agitation.

Is PT-141 (Bremelanotide) lawful to purchase and possess for laboratory research in the United Kingdom?

Yes. Non-scheduled synthetic research peptides like PT-141 (Bremelanotide) are entirely legal to acquire, import, and hold for bona fide laboratory experimentation in the UK. However, under Regulation 46 of the Human Medicines Regulations 2012 (SI 2012/1916), supply or marketing for human clinical administration without MHRA authorization is strictly unlawful.

UK Academic MonographNeuropeptides & CNS SignalingIn Vitro Laboratory Only

PT-141 (Bremelanotide)

Q: What is the CAS registry number, molecular formula, and mass of PT-141 (Bremelanotide)?

PT-141 (Bremelanotide) (Cyclo(1,6)-Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-OH) is indexed in the CAS Registry under #189722-12-9. Its empirical molecular formula is C50H68N14O10 with a monoisotopic molecular weight of 1025.18 g/mol. It is cataloged under the Neuropeptides & CNS Signaling research classification.

Q: What are the storage temperature thresholds and solution kinetics for PT-141 (Bremelanotide)?

Lyophilized vials require desiccated storage at -20°C desiccated in inert argon atmosphere (stable up to 24 months). Once reconstituted into an aqueous solvent, the peptide solution must be stored at 2°C to 8°C refrigerated; protect from direct actinic light (stable 21 days) protected from UV degradation. The laboratory stability window is Susceptible to photolytic oxidation at Trp residue and deamidation above pH 7.5. Avoid repeated freeze-thaw cycles.

Cyclo(1,6)-Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-OH

Storage Baseline-20°C Lyophilized

Assay VehicleBAC Water / Saline

Target SignalingNeuropeptides & CNS Signaling

HPLC Standard≥98.0% Purity

Quick Section Jump:#Verified-Suppliers #Reconstitution-SOP #FAQs

PubChem Molecular SpecsValidated

CAS Registry:189722-12-9

Chemical Formula:C50H68N14O10

Monoisotopic MW:1025.18 g/mol

PubChem CID:9941379

Primary Amino Acid Sequence (7 residues)

N-terminus → C-terminus

1Ac-Nle

2Asp

3His

4D-Phe

5Arg

6Trp

7Lys

Pre-Clinical Overview & Monograph Profile

PT-141 (Bremelanotide) is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (alpha-MSH) characterized by an intramolecular lactam bridge. Widely investigated across neurochemical laboratories as a selective agonist of central melanocortin MC3 and MC4 receptors.

Independent Laboratory Audit

Verified UK Suppliers for PT-141 (Bremelanotide)

5 Audited British & European Sources

Supplier	Assay Purity	Reagent Format	Dispatch Location	Notes	Access
PharmaGrade Store	≥99.3% (HPLC)	vial	United Kingdom (Royal Mail 24)	Lyophilized 10mg reagent vials with UK analytical batch chromatograms.
Direct Peptides	≥99.0% (HPLC)	vial	UK Hub & Europe	Solid-phase cyclic peptide synthesis featuring certified purity analysis.

Biochemical Mechanisms of Action

Molecular Signaling Pathways

1Selective agonist for central melanocortin MC3R and MC4R G-protein coupled receptors.
2Stimulates downstream central neurotransmission pathways in the medial preoptic area of the hypothalamus.
3Cyclic lactam bridge between Asp2 and Lys7 confers enzymatic stability against neutral endopeptidases.
4Modulates central neurochemical cascades without operating through peripheral vascular or nitric oxide mechanisms.

Pre-Clinical Laboratory Handling

Laboratory Evaluation Guidelines

Extensively investigated across academic neurochemical facilities for central receptor pharmacology, neuroendocrine signaling, and behavioral pathway modulation. Formulated strictly for in vitro academic and biotechnological assay models.

Aseptic Dissolution & StorageUK Lab Standard

Recommended Diluent:Bacteriostatic 0.9% Benzyl Alcohol USP or Sterile Reconstitution Diluent

Lyophilized Storage:-20°C desiccated in inert argon atmosphere (stable up to 24 months)

Reconstituted Storage:2°C to 8°C refrigerated; protect from direct actinic light (stable 21 days)

Solution Stability:Susceptible to photolytic oxidation at Trp residue and deamidation above pH 7.5

Academic Biochemical Monograph

Receptor Affinity, SPPS Synthesis & Pharmacokinetics

Standardized chemical parameters, solid-phase synthesis criteria, and quantitative receptor affinity benchmarks for PT-141 (Bremelanotide).

Target ReceptorsBinding Kinetics

Primary Receptor Cascade

Melanocortin Receptor Subtypes 3 and 4 (MC3R / MC4R)

Binding Affinity (Kd / Ki)

Ki = 34 nM (MC4R selective agonism)

Receptor Family

Class A Rhodopsin-like G-Protein Coupled Receptor (GPCR)

Downstream Effectors

Gs-protein activation stimulating adenylate cyclase and cAMP generation
Activation of protein kinase A (PKA) in hypothalamic neuronal circuits
Modulation of dopamine and norepinephrine neurotransmission in mPOA

SPPS MethodologyISO Criteria

Synthesis Protocol

Fmoc SPPS with on-resin cyclization via Asp-Lys lactam bridge formation

N-Terminal / C-Terminal Mod

Acetyl group (Ac-Nle-) · Free carboxyl (-Lys-OH) or carboxamide

Acid Cleavage Cocktail

TFA / TIS / EDT / H2O (94:2.5:2.5:1 vol/vol)

HPLC Retention Standard

RP-C18: 8.65 min (0.1% TFA / ACN linear gradient)

PharmacokineticsIn Vitro / In Vivo

Elimination Half-Life

t1/2 ≈ 2.7 hours; cyclic configuration prevents rapid exopeptidase degradation

Primary Degradation Pathway

Hepatic metabolism and peptide hydrolysis; 65% excreted via urine, 23% in feces

Bioavailability Profile

Rapid mucosal and subcutaneous uptake with minimal plasma protein binding

Renal Filtration Threshold

Molecular mass 1,025.18 Da cleared via glomerular filtration

Quantitative Pre-Clinical & Clinical Evidence Matrix

Documented Biochemical Endpoints & Statistical Significance

Study Design	Cohort (n)	Measured Biological Endpoint	Statistical Significance	NCBI Citation
Double-Blind RCT	n = 1,247 randomized cohort (RECONNECT)	Primary behavioral and satisfaction endpoints across 24 weeks	p < 0.001 vs placebo	PMID 31599839

Peer-Reviewed Academic Citations

Indexed Scientific Literature

Bremelanotide for Female Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials (RECONNECT)

Obstetrics & Gynecology (2019) · Clayton AH, Kingsberg SA, Rosen RC, et al.

Key Finding: Demonstrated central MC4R activation efficacy across double-blind multicenter randomized cohorts.

PubMed PMID: 31599839

BIOCHEMICAL & REGULATORY Q&A

Curated Scientific Q&A for PT-141 (Bremelanotide)

Authoritative pre-clinical, analytical, and statutory handling guidelines for laboratory researchers.

5 Curated Questions

PT-141 (Bremelanotide) (Cyclo(1,6)-Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-OH) is indexed in the CAS Registry under #189722-12-9. Its empirical molecular formula is C50H68N14O10 with a monoisotopic molecular weight of 1025.18 g/mol. It is cataloged under the Neuropeptides & CNS Signaling research classification.

Statutory / Academic Citation: PubChem CID 9941379; British Pharmacopoeia Appendix III

Biological Pathway Correlates

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Human Trial Data

CAS 80714-61-0

Semax

Heptapeptide ACTH(4-10) Analog (Met-Glu-His-Phe-Pro-Gly-Pro)

C37H51N9O10S813.92 g/molNeuropeptides & CNS Signaling

Semax is a synthetic regulatory heptapeptide structurally derived from an adrenocorticotropic hormone fragment (ACTH 4-10) stabilized with a C-terminal Pro-Gly-Pro tripeptide. Examined in neuropharmacology laboratories for its modulation of BDNF, trkB receptors, and cerebral monoamines.

Available Laboratory Formats:

vialspraypen

Purity ≥98.5% HPLCView Monograph

Human Trial Data

CAS 129954-34-3

Selank

Synthetic Tuftsin Heptapeptide Analogue (Thr-Lys-Pro-Arg-Pro-Gly-Pro)

C33H57N11O9751.88 g/molNeuropeptides & CNS Signaling

Selank is a synthetic regulatory heptapeptide derived from the immunomodulatory tetrapeptide tuftsin, extended with a C-terminal Pro-Gly-Pro tripeptide. Examined in neuroimmunology laboratories for its allosteric modulation of GABAA receptors, enkephalinase inhibition, and IL-6 expression.

Available Laboratory Formats:

vialspray

Purity ≥98.5% HPLCView Monograph