ABSTRACT
The eld of controlled drug delivery has led to the development of smart drug delivery systems (SDDSs), which are also known as stimuli-sensitive delivery systems. The concept of SDDS is based on rapid transitions of a physicochemical property of polymer systems upon imposition of an environmental stimulus, which include physical (temperature, mechanical stress, ultrasound, electricity, light), chemical, (pH, ionic, strength), or biological (enzymes or biomolecules) signals. Such stimuli can be either “internal” signals, resulting from changes in the physiological condition of a living subject, or “external” signals articially induced to provoke desired events. As illustrated in Figure 9.1 SDDS provides a programmable and predictable drug release prole in response to various
9.1 Introduction ..........................................................................................................................245 9.1.1 Biological Stimulus-Responsive Drug Delivery Systems ......................................... 247
9.1.1.1 Glucose-Sensitive Gels ..............................................................................248 9.1.1.2 pH-Sensitive Membranes ...........................................................................249 9.1.1.3 Con A-Immobilized Systems .....................................................................250 9.1.1.4 Sol-Gel Phase Reversible Hydrogel Systems ............................................ 251
9.1.2 Glutathione-Sensitive Gels ....................................................................................... 251 9.1.3 Antigen-Sensitive Gels ............................................................................................. 252 9.1.4 Gels Sensitive to Other Analytes .............................................................................. 253
9.2 Magnetic-Sensitive Drug Delivery Systems .........................................................................254 9.3 Electric Field-Responsive Drug Delivery Systems .............................................................. 255 9.4 Redox Potential-Sensitive Drug Delivery Systems ..............................................................256 9.5 pH-Responsive Drug Delivery Systems ...............................................................................256
