Endotoxin
is a major constituent of the outer cell membrane of gram negative bacteria.
Typically, endotoxins are released to surroundings when the bacterium dies and
the cells are disrupted. Since bacteria can grow in nutrient-poor media such as
water, saline, and buffers, endotoxins are found almost everywhere. Due to
their ubiquitous nature, endotoxins are persistent biocontaminants that deposit
and adhere to many materials. High concentrations are found where bacteria
accumulate or are to be used for technical purposes, such as in bioprocessing.
In
relation to this, Jyothi Thundimadathil has written an article for Controlled
Environments.
Here
is an extract:
“Though
most peptides are made synthetically, Part 21 CFR 601.2 of U.S. Food and Drug
Administration (FDA) regulations classifies peptides as specified biologics.
Therapeutic quantities of most macromolecules do not pass easily through the
skin or mucus membranes without penetration-enhancing techniques, such as
detergents or electric impulses, increasing the likelihood of irritation or
other side effects. For this reason, many protein and peptide drugs have to be
delivered by injection or a nano-needle array.
As
long as endotoxins get into contact with the skin or digestive system, they are
tolerated quite well (certain lung diseases are known to be linked to endotoxin
inhalation). For breathing, the limit for endotoxin in air is fixed at 20 ng/m3
or 200 EU/m3. For intravenous applications, the limit is 5 EU/kg body weight an
hour according to European Pharmacopoeia, 1997. The term EU denotes the
biological activity of endotoxins—one unit of EU corresponds to 100 pg of
standard endotoxin.”
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