This study characterized the degradation of bremelanotide (PT-141) under forced stress conditions and identified eight degradation products. The peptide was particularly susceptible to oxidative stress, with additional degradation under thermal, photolytic, acidic, and basic conditions, and the authors used computational modelling to predict epimerization sites and toxicity.
Journal article — Laboratory stress-degradation and method-development study. Interventions: bremelanotide acetate (PT-141).
The RP-HPLC method was partially validated and showed satisfactory system suitability, precision, and accuracy, with linearity over 25–150 µg mL−1 (r2 = 0.9993). In forced-degradation studies, bremelanotide degraded less under acidic than under basic conditions and was markedly susceptible to oxidative stress; degradation also occurred under thermal and photolytic stress. Eight degradation products were detected and characterized by LC-HRMS/MS. The major pathways were deacetylation, peptide-bond hydrolysis, oxidation, and epimerization; probable epimerization sites were predicted from steric energies and MS/MS fragment intensities. ProTox-3.0 predictions placed most degradation products in toxicity class 5 and two hydrolytic products in class 4.
This paper provides PT-141 researchers with a detailed degradation and impurity profile for bremelanotide, along with an RP-HPLC method useful for quality control and formulation development. It does not establish the biological activity, safety, or clinical efficacy of bremelanotide or its degradation products.
Peptide profiles: PT-141.
All indexed evidence: PT-141 trials & papers.
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