Drug delivery systems(DDS)I The definition, characteristic and classification of DDS
Qian Chunmei(Dept. of Pharmacy, Xi'an Medical University, Xi'an 710061)
Drug delivery systems (DDS) are defined as modern pharmaceuticalpreparations in which the release rate and delivery location of the drug are controlled in apredictable manner. Their main characteristic is the highest effect, lowest adverse reactionand best compliance to patients. They can be classified into rate-preprogrammed, activation-modulated, feed back-regulated and site-targeting DDS based on drug release andtechnical principles.