Pyrogens bacterial

The General Tests and Assays. This section of the USP gives methods for tests that are general in nature and apply to a number of the substances. Procedures are iacluded for such tests as heavy metals, melting point, chloride, sulfate, sterility, bacterial endotoxins, and pyrogens. Also iacluded are descriptions of various analytical techniques, such as spectrophotometry, chromatography, and nmr, and descriptions of tests to be used on glass or plastic containers, mbber closures, etc. 

Distilled water is often used in the formulahon of oral and topical pharmaceutical preparations and a low bacterial count is desirable. It is also used after distillation with a specially designed still, often made of glass, for the manufacture of parenteral preparations and a post-distillation heat sterilization stage is commonly included in the process. Water for such preparahons is often stored at 80°C in order to prevent bacterial growth and the production of pyrogenic substances which accompany such growth. 

In the case of injectables and ophthalmic preparations which are manufactured aseptically but do not receive a sterilization treatment in their final container the packaging has to be sterilized. Dry heat at 170°C is often used for vials and ampoules. Containers and closures may also be sterilized by moist heat, chemicals and irradiation, but consideration for the destruction or removal of bacterial pyrogens may be necessary. 

D12. DeRijk, R. H., Van Rooijen, N. Tilders, F. J. H., Besedovsky, H. O., Del Rey, A., and Berken-bosch, F., Selective depletion of macrophages prevents pituitary-adrenal activation in response to subpyrogenic, but not to pyrogenic, doses of bacterial endotoxin. Endocrinology 129, 330-338(1991). 

The structure of the native immunostimulatory MDPs was found to be IV-acetyl muramyl-L-alanyl-D-isoglutamine. (/V-Acetyl muramic acid is a base component of bacterial peptidoglycan.) Native TDM is a potent pyrogen and is too toxic for general use as an adjuvant. The molecular basis underlining MDP s adjuvanticity remains to be fully elucidated. Administration of MDP, however, is known to activate a number of cell types that play direct/indirect roles in immune function, and induces the secretion of various immunomodulatory cytokines (Table 13.14). 

US FDA, ITG subject bacterial endotoxins/pyrogens. In Office of Regulatory Affairs (Ed.), Inspector s Technical Guide, Washington, DC, 1987. 

The results from all biological assays performed showed that chemically synthesized E. coli lipid A (compound 506 or LA-15-PP) expresses, with similar doses, the same spectrum of endotoxic effects as bacterial (E. coli) free lipid A (5,234-237). Thus, lipid A constitutes the lethal, pyrogenic, leukopenic, and mediator-inducing, that is, the endotoxically essential region of LPS, its endotoxic properties being embedded in a molecule having the structure shown in Fig. 2. 

The opposite of harmony is disharmony. An example of disharmony is the need to repeat tests using rabbits for pyrogen where testing for bacterial endotoxin is otherwise prescribed. This represents the most extreme disharmony of methods. But there is even a greater disharmony, and that would be to reach different eonelusions as to pass/fail the speeimen. In this ease, the quality control professionals must make a judgment as to whether or not this material can be sold in one or more regions. Functionally equivalent to harmonization is the absence of disharmony. Because of a difference in policy, pharmacopoeias may not differ on adoption of a test at all. If certain tests are eonsidered neeessary by one pharmacopeia in order to protect the consumer, it is appropriate for that pharmacopeia to adopt the test without reference to any other region. 

Pyrogens (e.g., bacterial matter) elevate—probably through mediation by prostaglandins (p. 196) and interleukin-1—the set point of the hypothalamic temperature controller (B2). The body responds by restricting heat loss (cutaneous vasoconstriction chills) and by elevating heat production (shivering), in order to adjust to the new set point (fever). Antipyretics such as acetaminophen and ASA (p. 198) return the set point to its normal level (B2) and thus bring about a defervescence. 

Bacterial enck)toxin pass the water through a pyrogenic connection for about 1 minute and then collect the sample in a pyrogenic bottle. All materials coming in contact with test materials and reagents must be pyrogen free and careful technique is essential to prevent contamination with environmental endotoxin. 

Endotoxins are bacterial cell envelope constituents that, when present in pharmaceutical products, cause pyrogenic reactions sometimes resulting in lethality. The toxicity of endotoxins is directly related to their chemical composition. However, the viability of the organism is irrelevant since endotoxin derived from dead or live microbes is equally active. The classical endotoxin is lipopolysaccharide (LPS). However, peptidoglycan (PG) also displays endotoxin-like activities. LPS is found only in gram-negative bacterial outer membranes, while PG is present in the cell... 

The hallmark of a bacterial infection is fever due to LPS pyrogenicity. It may have some relevance in cancer as hyperthermia is tested as a cancer treatment on its own, as reviewed by Christophi et al. [58], This effect is mediated by cytokines (mainly IL-1(3) produced in response to LPS. 

Watson, D.W., and Kim, Y.B7T1963). Modifications of host response to bacterial endotoxins. I. Specificity of pyrogenic tolerance and role of hypersensitivity in pyrogenicity, lethality, and skin reactivity. J. exp. Med., 1 18, 425-446... 

The endotoxlc activity associated with Gram-negative bacterial infections resides in the lipophilic lipid A part of the LPS molecule (1). This toxic activity manifests itself in a number of ways, e.g., pyrogenicity, transient leucopenla followed by leucocytosis, hypotension, bone marrow necrosis, abortion, the Shwartzman reaction, etc. As a consequence the commonly used killed whole cell enterobacterial vaccines have to be given in... 

The USP now recognizes two tests—the pyrogen test conducted with rabbits and the bacterial endotoxins test, also termed the limulus amebocyte lysate... 

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