PT-141 10mg

Description

PT-141 (Bremelanotide) Overview

PT-141 is the development code for bremelanotide, a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone. It came out of structure-activity work on melanotan II and differs from it at the C terminus: the C terminal amide of melanotan II is replaced by a free carboxylic acid, which is why the two have different molecular formulas.

Relationship to the approved medicine
Bremelanotide is an approved medicine in the United States. It is marketed as Vyleesi, approved on 21 June 2019, for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women, where low sexual desire causes marked distress or interpersonal difficulty and is not attributable to a coexisting medical or psychiatric condition, relationship problems, or the effects of another medication. Vyleesi is a manufactured, quality-controlled drug product supplied under a prescription label. The material in this vial is a research chemical. It is not Vyleesi, it is not a drug product, and it carries no Drug Identification Number in Canada.

Technical Specifications

• Peptide Name: PT-141 (bremelanotide)
• Systematic Name: N-acetyl-L-norleucyl-L-alpha-aspartyl-L-histidyl-D-phenylalanyl-L-arginyl-L-tryptophyl-L-lysine (2-7)-lactam
• CAS Number: 189691-06-3 (free base)
• Molecular Formula: C50H68N14O10 (free base). The approved drug product is the acetate, C50H68N14O10 with one to two equivalents of acetic acid.
• Molar Mass: 1025.2 g/mol (free base)
• Purity: ≥99.0% (determined by HPLC)
• Appearance: White to off-white lyophilized powder
• Solubility: Soluble in sterile water

Research Context
The prescribing information for the approved product describes bremelanotide as a melanocortin receptor agonist that non-selectively activates several receptor subtypes, with the following order of potency: MC1R, MC4R, MC3R, MC5R, MC2R. At therapeutic dose levels, binding at MC1R and MC4R is described as the most relevant. Points that follow from that pharmacology:

• Receptor pharmacology: The compound is used in binding and functional assays across the melanocortin receptor family, and as a comparator when characterising subtype-selective ligands.
• MC4R distribution: Neurons expressing MC4R are present in many areas of the central nervous system, which is the basis for studying this receptor family in the brain.
• MC1R and melanin: MC1R is expressed on melanocytes, and binding at that receptor leads to melanin expression and increased pigmentation.
• Mechanism not established: The approved label states that the mechanism by which the medicine improves HSDD in women is unknown. Any description of a downstream pathway for this compound should be treated as a hypothesis, not a finding.

These points describe pharmacology and laboratory use. Nothing here describes an effect in a person or an animal outside a controlled study.

Storage and Handling

• Lyophilized (powder): Store at minus 20 degrees Celsius, sealed and protected from light and moisture; see the batch documentation for the retest date. Avoid repeated freeze-thaw cycles.
• Reconstituted (liquid): Keep refrigerated at 4 degrees Celsius and protected from light. The retest date in the batch documentation applies to the sealed lyophilized vial only.
• Handling: Standard laboratory safety protocols apply. This product is for laboratory research use only.

Testing and Quality Control
Every batch of PT-141 10mg is released against the following checks:

1. HPLC: to confirm a purity profile of ≥99.0%.
2. MS (mass spectrometry): to confirm the molecular weight and identity of the cyclic peptide.
3. Visual verification: to confirm the integrity of the lyophilized cake.

For laboratory research use only. Not for human or veterinary use.

Further reading

• What is PT-141 (bremelanotide)?
• How to store peptides: lyophilized vs reconstituted