Other breath-activated inhalers are also called dry powder inhalers. These inhalers do not contain the pressurised inactive gas to propel the medicine. You don't have to push the canister to release a dose. At standard inhaled doses, the amount of medicine is small compared with tablets or liquid medicines. Therefore, http://ezproxy.cityu.edu.hk/login?url=https://tr.wikipedia.org/wiki/Vitamin