Sustained release (water absorption)—drug delivery system

Publisher Summary Drug delivery that employs hydrogels is important because drug delivery systems (DDS) are able to control both concentration and distribution of the drug in the body with the aid of stimuli-responsive polymers. Besides the quantitative control of drug delivery, studies related to timing control techniques, kinetic analysis based on the transfer phenomenon, on-off control of drug delivery, and auto feedback drug systems are discussed in the chapter. DDS that utilize structural changes in stimuli-responsive polymer gels are described in the chapter. The chapter also explains the mechanism of swelling and shrinking of polymer gels, and drug delivery using such behaviors. Pulse-like drug delivery using reversible swelling-shrinking of gels is also discussed in the chapter. It is possible to achieve control of the amount and time of drug delivery because these new stimuli-responsive gels change their structures and functions based on the changes in external conditions. It is therefore indispensable to study detailed mechanisms of dynamic structures and drug delivery behavior using a deductive approach that taps polymer science, pharmaceutical engineering, and chemical engineering. Major advances in the DDS technology are expected in the near future.