Endotoxin

Endotoxins are lipopolysaccharide (LPS) complexes embedded in the outer membrane of Gram-negative bacteria that are released upon bacterial cell death or division. They are among the most potent pyrogens known, capable of triggering fever, hypotension, and systemic inflammatory responses at concentrations as low as nanograms per kilogram of body weight. Endotoxins are heat-stable and resistant to standard autoclaving, making them a persistent contamination concern in pharmaceutical and peptide manufacturing. Detection is performed using the Limulus Amebocyte Lysate (LAL) assay, derived from horseshoe crab blood cells, or the recombinant Factor C (rFC) assay. The FDA and EMA set strict endotoxin limits for injectable products, typically less than 5 EU/kg body weight per hour. In peptide research, endotoxin testing is a critical component of quality assurance, and reputable suppliers include endotoxin levels on their Certificates of Analysis. ORYN's peptide pens undergo rigorous endotoxin testing to ensure levels fall well below regulatory thresholds.