Submitted by vijayaratna on Mon, 08/16/2010 - 16:38
For the parenteral products, the most usual vehicle is water. Water is most abundantly available, cheap, safe, non-toxic and non-irritating. But anything that is to be administered parenterally has to be sterile and apyrogenic. Apyrogenesity means lack of pyrogens. Pyrogens are the metabolic products of bacteria. In making a vehicle suitable for parenteral preparation, we may sterilize it by autoclaving, which would kill the vegetative organisms as well as the spores. But the water once had organisms living in it and their metabolic products now stay in the water. These products are not destroyed by autoclaving. Since they cannot be destroyed at the usual autoclaving temperature, they must be prevented from getting into water. So the water being taken for parenteral preparation must be apyrogenic. Pyrogens can cause a lot of damage, if they are injected into a human being. Hence every batch of injections is tested for the presence of pyrogens. The word "pyrogens" means, "fever producing".