Pharmacokinetics · PK Reference
Pharmacokinetic Profile
Concentration-time behavior of bremelanotide following subcutaneous administration. Data derived from published Phase I/III clinical pharmacology studies.
Tmax
~60 min
Subcutaneous
t½
~2.7 h
Elimination half-life
Cmax
Dose-dependent
Linear PK
Vd
~40 L
Distribution volume
Protein Binding
~21%
Plasma protein
Metabolism
Proteolytic
No CYP450
Excretion
Urine (~64%)
Fecal (~22%)
Bioavailability
~100%
SC route
Plasma Concentration (% Cmax) vs. Time
Subcutaneous injection · Normalized concentration · Schematic representation
Metabolic Pathway
Bremelanotide undergoes non-CYP450 proteolytic cleavage. This means minimal drug-drug interaction risk with common CYP-metabolized compounds. No hepatic first-pass elimination with SC route.
Subcutaneous Depot Behavior
Following SC injection, the peptide forms a local depot in subcutaneous tissue. Absorption into systemic circulation is sustained, yielding a predictable Tmax of approximately 60 minutes in most subjects.
Renal Considerations
Primary excretion is urinary (~64%). Dose adjustment guidance exists for severe renal impairment in FDA labeling. Moderate impairment does not require adjustment per pharmacokinetic studies.
Inter-Individual Variability
CV% for Cmax and AUC is approximately 30–50% across subjects. Body composition, injection site, and subcutaneous tissue perfusion all contribute to observed variability.