Endotoxin background

Bacterial Endotoxin

Sterile Products “The manufacture of sterile products is subject to special requirements in order to minimise risks of microbiological contamination, and of particulate and pyrogen contamination.”

Pyrogen Pyro + Gen Pyro = burning or fire Gen = produce or beginning

Pyrogen Any substance that can produce a rise in the body temperature ( i.e. produces a fever response )

Classification of Pyrogens • Exogenous pyrogens – Any substance foreign to the body capable of inducing a febrile response upon injection or infection and wound • Endogenous pyrogens – Is a substance that is produced by the host following the administration of an exogenous pyrogen and which are responsible for mediating the body’s inflammatory, coagulation, and fever mechanisms

Exogenous pyrogens • Microbial Pyrogens – Bacterial Endotoxins – Peptidoglycans (gram positive bacteria) – Virus – Fungi & Yeast • Nonmicrobial Pyrogens – Antigen – Steroids – Chemical – Drug

Structure of endotoxins • Produced mostly by gram-negative bacteria • endotoxin - complex of pyrogenic lipopolysaccharide, a protein and inert lipid; • lipid part of the lipopolysaccharide is the main pyrogenic agent; polysaccharide part increases solubility

Diagram of GNB Cell Membrane

Microbial cell wall structures Peptidoglycan Outer membrane Cytoplasmic membrane Gram-positive Gram-negative Fungi bacteria bacteria Capsule O-specific Polysaccharide b-Glucan, Chitin polysaccharide

The Story of LAL

Bacterial Endotoxins Test • USP XX(1980) • to detect or quantify endotoxins, cell wall component of gram-negative bacterial origin • reagent:amoebocytelysate from horseshoe crab (Limulus polyphemus or Tachypleus tridentatus). • The name of the test is also Limulus amebocyte lysate (LAL) test