ABSTRACT
Lipopolysaccharide (LPS), the biochemically purified endotoxic or pyrogenic structural
molecule unique to the gram-negative bacterial cell wall, is easily detected and quantified
using an in vitro assay referred to as the limulus amebocyte lysate or LAL test. LAL is a
very sensitive reagent made from the soluble protein extract or lysate of horseshoe crab
(genus Limulus) blood cells (amebocytes). Endotoxins from gram-negative bacteria (classified on the basis of their cell wall
structure) are the most common contaminants of water systems and biologically derived
materials and are resistant to most methods of sterilization. Very low concentrations of
endotoxins or LPS are toxic in vivo in blood or cerebral spinal fluid (FDA, 1987) and
may affect the growth and function of vertebrate cells in vitro (Gould, 1984). Because
LPS is a potential toxic contaminant of Pharmaceuticals, its detection in finished products
and its control or removal from parenteral and medical devices is especially important to
the pharmaceutical industry.
