ABSTRACT
Polysaccharides are ubiquitous biopolymers built from monosaccharides. Due to the presence of various derivable groups on molecular chains, polysaccharides can be easily modied chemically and biochemically, resulting in many kinds of polysaccharide derivatives. Polysaccharides are gaining increasing attention as components of stimuli-responsive drug delivery systems (DDSs), particularly since they can be obtained in a well-characterized and reproducible way from natural sources [1]. They are usually renewable, nontoxic, and biocompatible, and show a number of specic physicochemical properties that make them advantageous for different applications in DDS. Hydrogels are three-dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological uids and have a wide variety of biomedical applications [2]. Polysaccharide-based hydrogels have potential application as DDS, as the issues of safety, toxicity, and availability are greatly simplied. Drug delivery is an intriguing eld of research that has captured the interest of researchers because delivering a medicine to its site of therapeutic action is one of the main limitations of pharmaceutical and biotechnology industries [3]. DDSs have the advantage of increasing the residence time of a drug within a patient, reducing dosing frequency and toxic effects, and improving patient compliance and consequently efcacy with most dosage requirements. The ideal drug delivery carriers will ensure that the drug is released at the right site, in the right dose, and for the required time. They will also be biocompatible or biodegradable [3]. Recent efforts in drug development resulted in a number of controlled DDS consisting of a drug encapsulated within a suitable polymer carrier that enables drugs to be delivered either via novel routes or in a sustainable fashion or both. By selecting a biocompatible carrier, drugs could be made available at various locations in the body [4]. Stimuli-responsive smart materials such as thermo-responsive, pH-responsive, and electricalresponsive polymer and magnetic materials as DDS have achieved increasing attention for controlled release under specic conditions.
