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. The letters α and β[18] denote absolute stereochemistry at chiral centers—a specific nomenclature distinct from the R/S https://www.webwiki.co.uk/tr.wikipedia.org/wiki/Vitamin