Current trends and concepts in the design and development of nanogel carrier systems

Nanotechnology, a relatively novel technique, has much potential in smart drug delivery. Development of novel nanosized particulate drug delivery systems (DDS) may help in disease prevention, diagnosis, and treatment of many of the important diseases. Nanogels have particle sizes in the 0–100 nm range, and the three-dimensional network is maintained by varying the solvent quality. This review article describes concisely the current trends and concepts involved in the design and development of nanogel DDS. This review also explores the various approaches of drug loading, release mechanisms, characterization, and biomedical applications. Optimized nanogel systems can be developed on the basis of the site of action and pattern of drug release desired for improved therapeutic benefits. This can be achieved by using the appropriate method of preparation (physical or chemical) and drug loading mechanism by modifying the geometry and surface of the nanogels. The properties of nanogels are dependent on the constituent materials/components (synthetic or natural) and on external stimuli (pH, temperature, ionic strength or incorporation of hydrophilic residues) in the case of stimuli-sensitive nanogels. Due to the high stability, biodegradability, biocompatibility, large surface area, and minimal resources required for manufacture of nanogels, their applications (such as in oral, pulmonary, nasal, ocular, and topical routes) have gained special attention in the development of pharmaceutical drug carriers. Graphical abstract