loss on drying

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winzzz
winzzz's picture
loss on drying

USP specification; dry it at 50 and at the pressure not exeeding 5 mm of mercury  for 3 hours

i want to know....
if I use spec according to usp , i must use a  vacuum oven ?
how much a pressure in a hot air oven. ( i think the pressure not exeeding 5 mm  ? )

thank you for your kindness

Dr. Analytical
Dr. Analytical's picture
A hot air oven is at 760 mm

A hot air oven is at 760 mm pressure (= 1 atmosphere).  To produce a vacuum less than 5 mm you will need a vacuum pump and vacuum oven. 

If you want to use this USP procedure you must have a vacuum oven.  A hot air oven will not be acceptable.