Since pyrogens are non-volatile they can only be carried by water droplets, once the feed water has been turned to steam.

What is importance of pyrogen test?

Pyrogen test is performed to check the presence or absence of pyrogens in all aqueous parenterals. Rabbits are used to perform the test because their body temperature increases when pyrogen is introduced by the parenteral route. For this test, three healthy rabbits are selected each weighing at least 1.5 kg.

What is the chemical nature of pyrogen?

Pyrogens include endotoxins (toxins derived from gram-negative-bacteria) and non-endotoxic pyrogens (substances derived from microorganisms other than gram-negative-bacteria, or from chemical substances).