Product analysis - Pharmaceutical Biotechnology: Concepts and Aapplications - page 192

Figure 7.6 Photograph of a modern protein sequencing system. Photograph courtesy of Perkin Elmer Applied
Biosystems Ltd, UK

clinically signifi cant in human medicine include E. coli , Haemophilus infl uenzae , Salmonella
enterica , Klebsiella pneumoniae , Bordetella pertussis , Pseudomonas aeruginosa , Chylamydia
psittaci and Legionella pneumophila .
In many instances the infl uence of pyrogens on body temperature is indirect. For example, entry
of endotoxin into the bloodstream stimulates the production of IL-1 (Chapter 9) by macrophages.
It is the IL-1 that directly initiates the fever response (hence its alternative name, 'endogenous
pyrogen').
Although entry of any pyrogenic substance into the bloodstream can have serious medical
consequences, endotoxin receives most attention because of its ubiquitous nature. Therefore, it is
the pyrogen most likely to contaminate parenteral (bio)pharmaceutical products. Effective imple-
mentation of GMP minimizes the likelihood of product contamination by pyrogens. For example,
GMP dictates that chemical reagents used in the manufacture of process buffers be extremely
pure. Such raw materials, therefore, are unlikely to contain chemical contaminants displaying
pyrogenic activity. Furthermore, GMP encourages fi ltration of virtually all parenteral products
through a 0.45 or 0.22 µm fi lter at points during processing and prior to fi lling in fi nal product
containers (even if the product can subsequently be sterilized by autoclaving). Filtration ensures
removal of all particulate matter from the product. In addition, most fi nal product containers are
rendered particle free immediately prior to fi lling by an automatic pre-rinse using WFI. As an
additional safeguard, the fi nal product will usually be subject to a particulate matter test by QC
before fi nal product release. The simplest format for such a test could involve visual inspection
of vial contents, although specifi c particle detecting and counting equipment is more routinely
used.
Contamination of the fi nal product with endotoxin is more diffi cult to control because:

• Many recombinant biopharmaceuticals are produced in Gram-negative bacterial systems; thus,

the product source is also a source of endotoxin.