Ionotropic Gelation and Polyelectrolyte Complexation: the Novel Techniques to Design Hydrogel Particulate Sustained, Modulated Drug Delivery System: a Review

The utilization of natural and chemically modified polysaccharides as a part of drug development has increased in the past two decades. Great attention has also been focused on biopolymer based hydrogels for use as potential carriers in controlled drug delivery. Hydrogels are three dimensional, hydrophilic networks capable of imbibing large amount of water or biological fluids, mimics biological tissues. Because of this nature, great attention was devoted to these systems for biomedical applications. Indeed, these networks can be made suitable as the modulated drug delivery devices by tuning the physicochemical properties of the hydrogels with varying the degree of crosslinking either by physical or chemical or physical-chemical means. Numerous approaches have been investigated for formulation of controlled release dosage forms of different therapeutic agents including proteins, peptides, and even cells. In this present review, an attempt was made to narrate the different natural polyanions and their mechanism to form cross-linked hydrogel beads. This review was also focused on various methods of preparation of beads. Here, it was also tried to explain the importance of ionotropic gelation and polyelectrolyte complexation approaches, as these methods show great promise as a tool for the development of encapsulation process. Each method has its own advantages as well as limitations. For further improvement in this area, it is important to understand the strength and drawbacks of each method. Hence, an attempt was also made to discuss the same.