Page 50 - Dosage 1-part2 -ebook_Neat

30/10/2025, 00:02 Pharmaceutical Solutions & Sterile Dosage Forms

Benzyl alcohol 0.9%
Methylparaben & Propylparaben 0.1-0.18%

NOTE: Quaternary ammonium salts (benzalkonium chloride) are not used as preservatives
in injections.

2. Absence of pyrogens

Parenteral solutions must be non-pyrogenic (pyrogen-free)
Pyrogens are fever producing endotoxins.
Found in the outer membrane of Gram-negative bacteria (most common such as LPS).
Pyrogens are composed of lipopolysaccharides; LPS (Lipid A linked to a central polysaccharide
core) which is released upon breakdown of the cell wall or bacterial cell lysis.

Characteristics of the pyrogens

Water soluble
Non-volatile
Pass through bacterial filters.
Heat stable.

Biological activity of pyrogens

Injection of pyrogens can produce toxic effects.
Contamination of LVP can specifically cause serious problems:

Lipid A can affect thermoregulatory centre in the brain (fever)
High doses of pyrogens will activate the coagulation system and produce shock and
ultimately death.

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